Cycling Science: Optimizing Your Wheels, Tires, & Tubes

Intro: This is the TriDot podcast. TriDot uses your training data and genetic profile, combined with predictive analytics and artificial intelligence to optimize your training, giving you better results in less time with fewer injuries. Our podcast is here to educate, inspire, and entertain. We’ll talk all things triathlon with expert coaches and special guests. Join the conversation and let’s improve together.

Andrew Harley: Hey folks! Welcome to the show. It is a bike episode today, specifically chatting about the science behind wheels, tires, and tubes. Nailing your wheel and tire setup is way more than just running the right PSI, so there’s lots to cover today. Joining us for this conversation is TJ Tollakson from Dimond Bikes. TJ is the owner of Dimond Bicycles, and the founder and CEO of Ruster Sports. He raced in the pro field for 16 years and has two IRONMN victories, one North American Championship title, and many more pro podium finishes on his résumé. He studied industrial engineering at the University of Iowa and now brings his love of triathlon and engineering prowess into creating the most advanced bikes on the planet. TJ, welcome back to the TriDot podcast!

TJ Tollakson: Awesome, thank you Andrew, great to be here!

Andrew: Also with us is Coach Jeff Raines. Jeff is a USA Triathlon Level II IRONMN U Certified Coach, and TriDot Master Coach, who has a Master of Science in Exercise Physiology, and was a D-1 collegiate runner. He has over 60 IRONMN event finishes to his credit, and has coached hundreds of athletes to the IRONMN finish line. Jeff has been training and coaching with TriDot since 2015. Hey there, Jeff!

Jeff Raines: Hey there, Andrew! You know, I’ve met TJ many times virtually, but I finally met him in person at IRONMN Texas back in April, and am excited to be recording a podcast today with TJ.

Andrew: I’m Andrew the Average Triathlete, Voice of the People and Captain of the Middle of the Pack. As always, we’ll roll through our warmup question, settle in for our main set conversation, and then wind things down with Vanessa interviewing a TriDot coach on the cooldown.

We've chatted about the best approaches to hydration with sports scientist Andy Blow from Precision Fuel and Hydration in Episode .101 of the TriDot podcast, and we learned that there is not a one-size-fits-all approach to hydration, because everyone loses a different amount of salt in their sweat. As someone with a high sweat rate, and someone who has suffered from cramping in the past, I was very keen to get a better understanding of how much salt I lose in my sweat. So I had a sweat test with Andy when he joined us for our TriDot Ambassador Camp in St. George, Utah. There, I found that I lose more than 12,000 milligrams of sodium per liter of sweat. After taking the test I received a personalized hydration plan, and was recommended their strongest electrolyte drink, PH1500, which is three times stronger than most sports drinks. It has been a total game-changer for me, particularly in the hot conditions where I train and race. If you've ever struggled with hydration issues like dehydration or cramps during long, hot sessions, it is worth checking out precisionhydration.com and finding your nearest center for a sweat test. You can also use their Fuel and Hydration Planner to get a free personalized strategy for race day, and don’t forget, as a listener of the show, you can get 10% off your first order of electrolytes by using the code TRI23 when checking out. Lots of good stuff, let’s get to it!

Warm up theme: Time to warm up! Let’s get moving.

Andrew: Every sport has a lingo and terminology that comes along with it. Some terms are more mainstream – you don’t have to be a massive sports fan to know what a touchdown is in American football – but others are more obscure. I, for one, as a tennis player, would not expect just anyone to be able to chat with me about the virtues of the semi-Western forehand grip on a tennis court. Thinking about the terms in sport that are more widely known – Jeff, TJ, for our warmup question today – what is a sports term that you should probably know, but you don’t? TJ Tollakson, what do you think?

TJ: For me, the obvious one that I struggle with still – and this is embarrassing, because I’ve got a mechanic who’s brother is a pro hockey player – would be icing. Icing is a tricky one, because icing means different things in different sports. Particularly in hockey, icing has its own terminology that means something totally different. It’s tricky, and most people don’t understand.

Andrew: Yeah, I know what icing is. I know there’s nuances to which lines the puck has to pass over before it reaches the end line, and thus is a candidate for icing, should the defensive team reach a certain spot. I don’t know the exact lines involved, but I know how that rule works, just from watching hockey. Mine, TJ – this question was inspired because I’ve been watching in the evenings the NBA playoffs and NHL playoffs. At the time this podcast is being recorded, both of those sports are about to start the finals, and my answer here is from watching NBA. It drives me absolutely insane, but I don’t know what a field goal in basketball is. I’ve watched basketball for years. I follow the Dallas Mavericks, I know most of the rules, I know what’s going on on the court of play. But they always reference, “Player X or LeBron James has 18 points, and he’s four of six on field goal attempts.” So I know it’s a type of point. I know there’s free throws, three-pointers, jump shots, I know it’s a type of basket. But I don’t know what makes a certain shot a field goal attempt. That’s my answer here. Jeff Raines, what do you got?

Jeff: You know, I played tons of sports growing up, but I never actually did play tennis and soccer. I like them both, I just never got super into them. So recently I was asked to coach my daughter’s soccer game, because the head coach was out of town.

Andrew: Yeah, Jeff’s a coach, he can handle it!

Jeff: Yeah, right? And the refs, they’re like seven years old all the way up to sixteen years old out there, and half the time they don’t even show up, so one of the coaches has to ref AND coach their team. Anyways, I was scared to death because I had to ref that game, and ten minutes before the game, I was like, “Wait, what’s the difference between a goal kick and a corner kick?” I had to Google it real quick. Then the whole game, I had to really be intentional. “Okay, what team kicked it out of bounds, and what side of the field were they on when they kicked it out of bounds?” I had to really focus. Anyways, that was mine, goal kick versus corner kick. I’ve got it now.

Andrew: Yeah, you had to Google it in the moment. Thank God for Google, I don’t know what our parents’ generation did before Google was in our pockets at all times, that’s for sure. Jeff, I’m curious, do you know what offsides is in soccer? Are you familiar with that one yet?

Jeff: I think that’s the line between the half court and the goal line that they can’t cross, when doing those goal kicks? I don’t know, that's a guess.

Andrew: Yeah, you’re wrong. That’s fine. That’s my question, you don’t know what it is. All good, you’ll get there! Guys, we’re going to throw this question out to you, our audience, like we always do. Make sure you are a member of the I AM TriDot Facebook group – tens of thousands of athletes talking swim, bike, and run every single day – it’s a great, positive environment. Every single Monday when the new show comes out, I ask the warmup question to the Facebook group. So go find the post asking you – of everything in sports, what is a pretty mainstream thing that you just don’t know what it is? Can’t wait to see what you have to say!

Main set theme: On to the main set. Going in 3…2…1…

Andrew: Triathletes and cyclists love talking about their bikes, and I of course am no exception. I am so impressed by the quality of my Dimond Marquise TT bike. Every detail has been carefully crafted and engineered by the team at Dimond Bikes. My Marquise, complete with a custom TriDot paint scheme, sits proudly on the set of the TriDot Triathlon YouTube show for our audience to see. Their bikes are industry-leading aerodynamic machines, and they look awesome. But even beyond that, Dimond as a brand knows how to take care of their athletes, and with five different tri bike models, as well as road, gravel, and mountain bikes, your next bike should absolutely be a Dimond. TriDot and Dimond are a dynamic race-day one-two punch. Dimond provides you with the Ferrari of bikes, and TriDot Training develops your engine. So we are excited to partner with Dimond on some really cool offers. If you are a new-to-TriDot athlete, we’re offering six months of the Mark Allen Edition of TriDot with the purchase of a Dimond bike. If you are already a TriDot athlete, we are offering a TriDot store credit with your new bike. Head to dimondbikes.com for all the info, and to dream up your very own Dimond bike.

When we ride a bike, all of our weight, our hopes, our dreams, our hydration, our nutrition, and all the material that makes up the bike itself, all of that is supported by five touch points – butt, hand, hand, tire, tire. In today’s conversation, Coach Jeff Raines and TJ Tollakson of Dimond Bikes will be talking with us about the tire-tire part of that equation, making sure we are making the most of the wheels, tires, and tubes that carry us from T1 to T2. TJ, from the Dimond mine, before we get to the science part here today – just from following Dimond on social media, some really cool announcements from the company – there is a new TT bike that you guys have released called the Ikon, that is out there for triathletes to check out, and there is an even newer bike than that, the hardtail version of your mountain bike, the Rock. Tell us about these new releases. 

TJ: Right, so the Ikon is a great bike that combines some of the superior aerodynamics of our top-of-the-line bike the Mogul, but at a much lower side force, meaning that when you lie to your crosswind, it pushes you to the side less. It’s a great offering, it’s also the lightest frame that we manufacture, so that’s a big bonus for a lot of people, too. Even though aerodynamics always trumps weight, there’s a lot of weight weenies out there, and they like the light bikes. The Ikon is our lightest bike. Then we have our hardtail mountain bike called the Rock Hard, and we have a full-suspension mountain bike called the Rock. Both of them are really sweet. We just debuted the Rock Hard hardtail bike at the Bentonville Bike Fest. For any triathlete who has never ridden a bike in Bentonville, Arkansas, that’s a challenge to you – you should go down there and check it out, because it is an absolute bike paradise. There are numerous ways to fall in love with riding a bike, and Bentonville shows you about all of them.

Andrew: Let’s get into the main topic today. We can nerd out on Dimond Bikes all day long, that’s for sure, so I’m going to move us into the topic. To state the tri-obvious, a bike needs wheels to roll. Triathletes can equip their bike with aluminum wheels, carbon wheels, shallow, medium, and deep-dish wheels. They can have different brake track surfaces, they come in different widths. TJ, what does an athlete need to consider when selecting or upgrading their wheelset?

TJ: Man, this is a huge topic to undertake in one podcast, but we’ll start here. In a typical sense, the deeper the rim on the wheel, the faster the wheel. That’s a generalization, but oftentimes that’s the truth behind it. When you’re talking about the speed of a certain wheelset, typically the number one factor that anybody has to overcome is air resistance. A more aerodynamic wheel makes the bike massively faster, so going to a deeper rim profile makes the wheel faster. There’s a lot of things that come into play – spokes, aero spokes, tri spokes, full disc wheels, there’s a lot of things to consider. Man, you could do a Ph.D. dissertation on just wheel choices, but the number one thing we want to look for wheels is, “What makes a wheel fast?” A deeper wheel is going to be a faster wheel, but it’s going to come at the expense of having more side force to it. There are some innovative products that are designed to increase aerodynamics and decrease side force, and we can chat about those a little bit, but the main thing you’re looking for is a huge speed increase. It’s true you can buy speed on a bike because of aerodynamic improvements, so buying faster wheels is one of the ways that you can take any bike and make it faster.

Andrew: Is there a reason for an athlete to consider an aluminum wheel over a carbon wheel? Should we just always be going for carbon at this point in the game, as prices have come down a little bit? What are your thoughts on some of those different things, as people might look at the different options in the marketplace?

TJ: There are some good budget aluminum wheel options out there. Those are typically heavier than their carbon counterparts. The strength is typically better on the carbon side, too, and the durability is definitely going to be better on the carbon side than aluminum. But you can still buy a set of nice aluminum wheels for about a third of the price of the carbon set, so if budget is really the most important thing, you can find a somewhat aero set of aluminum wheels. I don’t want to keep anybody out of the sport because, “I can’t show up for that triathlon because I don’t have carbon wheels.”

Andrew: You can, yeah!

TJ: Yeah, you don’t need to show up and race with carbon wheels. You can race with aluminum wheels and be fine. Just know that somewhere along the line, if you want to go even faster, carbon wheels are a very healthy option.

Jeff: Those who bike outside mainly have a heavier, more aluminum training wheel set, and then they swap out their race wheels for carbon wheels closer to race day or on race day. But then a level deeper than that, as most people are staying more and more indoors for safety and a number of other reasons, a lot are not having those training wheels or those aluminum wheels, they’re just buying the new bike with the race wheels on it, and they’re keeping that front race wheel on it when they bike indoors, and maybe a little bit of riding that they do outdoors. They’re just using their race wheels. You're seeing that a lot as well.

TJ: Yeah, that’s a great economy answer, as opposed to having two sets of wheels. There’s nothing wrong with riding around in race wheels. They’re durable, they’re going to last, the bearings were made to last thousands and thousands of miles. There’s very little risk to overusing your race wheels.

Andrew: TJ, to your point, I hundred percent agree. If budget-wise you have to have an aluminum wheelset, great. But if you can afford the carbon, train on the carbon, they’ll last and last and last. Obviously on the podcast, TJ, we’ve talked with you about Dimond Bikes, we know you’re the owner of that. People might not realize that you also produce a carbon wheel, Red Crown Wheels, that I just referenced a moment ago. So as a guy who designs and produces carbon wheels, your knowledge on this podcast is first-hand. Tell us this, when athletes are scanning the marketplace and they see some carbon wheelsets – some of them can run as low as $600 to $800 US, others come in closer to $3K – what makes the expensive wheels more expensive? What goes into engineering a top-notch wheelset?

TJ: There’s a lot. There’s a huge variance in products, like HED makes some wheels that are actually carbon and aluminum. They have an aluminum hoop, and then there’s a carbon fairing that the spokes run through to the aluminum hoop. That’s more of a budget design – you’re still using the aluminum, the carbon is not a structural part of the bike, so those wheels can be more affordable. Once we start going up in price, then we’re looking at things like if the wheel is structural, or how many spokes it has, how aerodynamic is the rim profile. Every cross-section of the wheel has its own challenges, either in manufacturing or aerodynamic improvements. Those things make a wheel more or less expensive. Older models are less expensive and a lot more affordable, because they make thousands and thousands out of a mold, whereas newer wheels out of new mold are more expensive because they have to recoup those manufacturing costs of making the mold for it. A lot of the trends that we see in more expensive wheels are wider rims that match the wider tires that we’re seeing more people ride on, and that’s one of the things we’re going to talk about today. Then we see things that are trending right now in terms of ways that you can reduce the spoke count of the wheel, or the side force placed on the wheel, while still maintaining the aerodynamics. Those are all trends, and that has a lot to do with how much you’re spending on a wheelset.

Andrew: Let’s talk just tires for a moment. Real sexy topic, everybody loves thinking about bike tires. First things first, there are different categories of tire. An athlete can run tubular tires, they can run clincher tires, or they can run tubeless tires. TJ, what is the difference between these three, and what should athletes be reaching for these days?

TJ: When I first started racing, the predominant race tire was a tubular tire. It’s kind of confusing when we talk about a tubular tire, because what does that mean? That means that there was a hand-sewn tire that had usually a latex inner tube sewn into the tire, and then that tire was glued to a rim. At that time it was mostly hard rims, and the reason those tires were the most popular was because they were the easiest to mount to a carbon rim, because you just glued it on. It was kind of a pain, because you had to stretch these tires over and you had to glue them on, and make sure the surface rough was right. Then the worst would be if you had a flat during a race, you would have to get this tire off and replace it with another whole tire and inner tube sewn into it, then you’re going to try to pump that up and ride it without any glue. So it’s a little bit of a scary thing about flats when you’re talking about tubeless tires, but we did it. There’s a famous scene from IRONMN, when Norman Stadler after he won his first title. He’s on the side of the road in Hawaii, and he’s yelling “Too much glue!” because he can’t get the flat, tubeless tire off of his rim. He just can’t do it. He’s got a thick German accent, and he’s just crying, “Too much glue! Too much glue!” Not that I’m poking fun at Norman, it’s just how much this sport has changed. After tubeless tires, we transition into clincher tires. The clincher bike tire was a revolutionary leap forward, because it made it way easier to change a flat tire. On top of that, because they were making clincher tires in a mold instead of hand-sewing them, the aerodynamics and manufacturing processes were so much superior to hand-sewn tubulars. The tires ended up becoming faster and more aerodynamic at the same time. Clincher tires mount on a rim that has a hook on it. There’s a little hook on the side of the rim that the tire hooks into so it can’t pull off of that. In between that area there’s an inner tube, either butyl or latex, and now there’s even plastic tubes that you can use now which are really cool.

Andrew: Really!

TJ: You put an inner tube inside the tire and then you inflate it, and the tire pushes out against the sidewall, and it has a hook so it can’t pop off. Really clever design. If you get a flat tire, which usually is the inner tube inside, you can pull that inner tube out, put a new one in, and keep riding. Very clever, very fast. Inner tubes made a huge difference in the speed, as did rim tape. Cloth rim tape is much slower than a hard plastic rim tape. Butyl inner tubes are a lot slower than latex inner tubes, and then they come out with these new inner tubes – Tubalito was the first big brand, but there’s other ones – they’re actually a plastic that’s molded, so they’re also really fast. The coolest thing about those inner tubes is they fold up to about the size of a pack of gum, it’s great technology. Then let’s take one more leap forward to where we are today. By no means are tubular tires no longer used, by no means are clincher tires no longer used, but right now the trend is in tubeless tires. Not tubular, not clincher, but tubeless. That means that you’re taking your carbon rim, you’re installing a tape over all the holes on the rim, and then you’re going to install a tire specifically designed to hold air, and seal against the rim so nothing leaks. You can do that oftentimes by just putting the tire on and pumping it up into a hole, other times you will need to seal that with a sealant inside. There’s all different companies that make sealant, from Silca to Stan’s to Muc-Off, all kinds of companies that make a sealant. It’s a latex-based sealant that actually plugs the holes, and the benefit of a tubeless tire is that if you run over a nail or thorn or staple in the road and it pokes a hole through the tire, that latex will spray out where the hole is and it will clog the hole, and you’ll just keep riding. You’ll lose a little bit of pressure in the tire, but if there’s enough sealant in the tire it will clog very quickly, and you’ll just keep riding, and in many cases you’ll have no idea that you actually had a flat during the ride. That’s probably the biggest advantage of going to a tubeless setup, is that the flat protection has improved dramatically. The other big thing is you’re reducing one component out of it, you’re taking the inner tube out, so you don’t need to worry about that, and the last thing is the rolling resistance is greatly improved. When we look at rolling resistance and aerodynamics, we’re saying that tubulars are kind of ancient history right now. They still have a purpose, they’re still used. Clincher tires were a mainstay for a good 15 years in that space, used in conjunction with really great tubes to make a very fast setup that was really easy to change. Now we have tubeless, which makes it even easier to change, has less rolling resistance, and greater puncture protection. That’s where we are with tires.

Jeff: Then let’s say you are in the middle of the race, and you have a tubeless tire, with a much less likelihood of getting a flat. But if you did have a full-force flat, you can still carry a clincher-based tube as a just-in-case, and you could potentially put that in there just to get you safely back to your car, or to the finish line or T2, without having to carry another whole tubeless tire out on course. You can still carry that flat kit with your tubeless tire, ride out in the elements, just to get you through that workout or race. Then once you got home, if the tubeless tire was completely destroyed, you would need to buy a new tubeless tire, and more sealant, and reinstall it. Is that correct?

TJ: That’s correct Jeff, you sound like a man speaking from experience! If you have a hooked tubeless rim, where there is still a hook on there that’s holding the tire in, you can always run a tube in there, and there’s no penalty. That’s totally fine. If you have a hookless rim, you want that inner tube just to be a temporary patch. Let’s say you have a flat in a race, and you have a hooked rim with a tubeless tire on it, and you put an inner tube in. You can leave it in there indefinitely if you want, it’s not going to create any harm, you’re not risking blowing the tire off or anything like that. The one thing that I will say is that tubeless tires typically run at a lot lower PSI than tubulars, which run at the highest PSI, and then clinchers at a medium PSI, and tubeless at lower. I don’t want to skip too far ahead, because I know this is all part of our discussion.

Andrew: Yeah, you’ve seen the question in advance. The last thing I wanted to touch on before we move on, is I know there’s a lot of folks listening who have a setup, probably with clinchers or tubular that they’ve had for years. They’ve probably heard rumblings on social media, or maybe on our last podcast episode where TJ joined us, where he advocated so strongly for tubeless setups. If there’s an athlete who’s aware that that’s the direction things are headed, and they currently have a clincher or tubular setup, what are the steps they need to take to switch over and modernize to a tubeless-ready system?

TJ: The reality is most clincher wheels can be converted to a tubeless system. Not every manufacturer is going to condone that, because they haven’t tested it themselves and don’t know what’s going to happen. Yes, you can take tubeless sealant tape, put it around the inside of your rim, put a tubeless valve in, put a tubeless tire on, and seal it. Will it work? Yes, almost all the time, that will work. Again, you want to be very careful, because the PSI that the tire and rim combination is going to be able to handle is going to be a lot lower with the tubeless setup than it was with the clincher, so you don’t want to go over the top with that. But you can convert most rims to tubeless if you want, and the best place to start, for anybody out there listening, is your local bike shop. Take it to a pro, because they’ve probably had this experience with mountain bikes, road bikes, even triathlon bikes in the past, so they can help you get set up, and stop you from making very costly mistakes, and save you a whole bunch of time.

Jeff: Yeah, I’ll even throw in that a lot of the tubeless conversion kits are designed for wider tires, and if you’re on an older tri bike that has a narrower rim, you need to be a little bit cognizant of the range or the width of the tubeless tire you’re going to put on there. Also, the older triathlon bikes don’t have as much clearance traditionally between the fork. Or the difference between a disc brake and rim brakes. Also, if you’re going to have a higher PSI or lower PSI, just know the clearance of the bike, so you’ve got a width and a clearance aspect. Just ask that local bike shop, again, before you just go buy the kit or buy some tires, take note of that as well.

Andrew: Great point Jeff, and more than likely the more modern your bike is, the newer bike is, they’re building them to accommodate wider rims. Conversely, the older your bike is, probably the more diligent you need to be in checking the specs of your bike, and what wheelset can be accommodated. One last question about tires and tubes before we move on into how it all marries together. I’m curious, TJ, for an athlete that does run a set of tubes, we don’t want to leave those folks out of this conversation today. To my knowledge, coming into this conversation, there was latex and butyl. I didn’t know that there was even plastic options for tubes, that’s news to me on this episode. What are the differences between all these options, and what is your recommendation for what tubes an athlete should be running in a tube setup?

TJ: For everyday training, athletes should be riding butyl tubes. They are relatively inexpensive, they’re very durable. The disadvantage is the rolling resistance is the highest, so they’re the slowest out of all the inner tube options. The preferred race tube has always been a latex inner tube. There are several different brands of latex inner tube that you can use. The reason latex tubes are so fast is they’re super flexible. The latex is very stretchy, and as you roll over something on the ground, the latex conforms and morphs into different shapes much easier than the butyl. It is a faster rolling resistance, they’re also lighter weight than most butyl tubes, so that helps the rotational inertia of the wheel as well. Just recently, in the last few years, these new plastic tubes were introduced. Tubalito was one of the first brands to do that, now all kinds of brands make them. Schwalbe makes one, but they’re made out of different plastics. Sometimes they even have a full plastic valve stem on them, but it’s lightweight plastic that is somewhat transparent, a translucent tube in a lot of cases. The Tubalito ones are orange. These tubes are faster than a butyl tube, not quite as fast as most latex tubes, but the biggest benefit to them is just the storage size. They pack down so small. I’ve got a TOTES box in my bike, so I’ve got a built-in flat storage kit. Of course space is at a premium, so I can pack two of those tubes in less space than I can pack one regular butyl tube, which is really important. The other thing that I try to remind people – and this is one of Lionel Sanders’ big learning experiences – is that if you’re running latex tubes, you don’t want to run a latex tube in your flat kit. The reason is the latex is extremely porous, so when you put CO2, carbon dioxide, into a latex tube, it seeps out of there at a much faster rate than it does out of a butyl tube. So at the end of a four-hour bike ride, you can have very little tire pressure left just from losing air out of the latex tube. So my recommendation for people is if you’re running a latex tube during a race, keep one of these Tubalito or Schwalbe plastic tubes in your flat kit, because they store a lot smaller, and it will hold air better than the latex tube if you’re using CO2 during biking.

Andrew: That was the most thorough and helpful four minutes on tubes I’ve ever heard in my entire life. Hats off, standing ovation for TJ Tollakson there. Moving us on a little bit, I want to talk about the width of tires. Now, my first set of tires I ever bought on my first road bike were 23 millimeters. I had never ridden a proper road bike with narrower wheels, so I vividly remember that feeling of going out onto the road and just perching my entire body on a 23 millimeter-wide stretch of rubber. I felt so wobbly, I probably looked as wobbly as a kid learning to ride for the first time. Since then, most of my racing days I’ve been on a 25-millimeter tire, and currently, my Dimond Marquise has a 25-millimeter tubeless tire. My Dimond Radiant road bike has a 28-millimeter tubeless tire. It seems, TJ, the trend lately is wider and wider tires coming into favor. Why is that, and how does tire width affect our ride?

TJ: There’s a couple things that have gone on. Andrew, I’m going to start by saying you’re not old enough to experience running on 19-millimeter tires, but when I first started, that’s what everyone was riding.

Andrew: I would have fallen over.

TJ: No, you wouldn’t have, but –

Jeff: With 130 PSI!

TJ: At least! Sometimes 180 PSI in those little tires. I’ll say this, I’ve known this, when Bradley Wiggins broke the hour record on the track – I don’t know if you remember when he was trying to do that – he also used 19-millimeter tires, pumped up to 130 PSI. This was on a velodrome, not on a road, so it has a very specific application. There’s no bumps, it’s very smooth. It’s designed for this, there is a purpose to this. But the thing that we found out is that as you’re riding on the road, rolling resistance is important, but there’s another thing. Josh Poertner from Silca, he used to be at Zipp, calls it “impedance”. He says that’s a bad term for it, but that’s the best he has for it. Impedance is the vibration from the road. Every road has a different vibration to it. When it’s perfectly smooth and brand new it has very little. Any crack or bump, or as you in Texas love to have is chip seal, creates a different vibration. The higher that vibration, then the slower the rolling resistance. Having too high a PSI in your tire actually creates bouncing of the entire system that slows it down. If we can keep the tire in contact with the road, and have some deformation of the tube in the tire or tubeless tire, then it will actually be faster, it will roll faster. The wider tire produces a shorter contact patch than the narrower tire, so there’s less life on the tire over the bumps, but the lower tire pressure is then absorbing those small bumps better than the higher PSI. It’s super complicated, there’s lots of things that come into play, but we look at it and say in general terms that yes, wider tires are becoming more popular. It’s been a trend since I first started, because we’re no longer on 19-millimeter tires. But there’s a tradeoff at some point, and that tradeoff happens on the aerodynamic side. When you’re Bradley Wiggins and you're trying to ride over 30 miles per hour for an hour, the aerodynamics are what trump the rolling resistance, that’s why he had high PSI and very narrow tires.

Andrew: And a perfectly smooth velodrome.

TJ: That’s right. You’ll still see that same thing in that a lot of the really fast pros might be on slightly narrower tires than the average age grouper. So 23’s are still used by some of the pros, especially on front wheels, where the rolling resistance becomes more important, versus the rear where the aerodynamics aren’t quite as important. But in general, yeah, we’re seeing a trend for wider and wider tires, which then give us a lower PSI, because we’re reducing that impedance. We’re trying to keep the tire on the ground, have it roll really fast, and still keep it aerodynamic. Now, you have to remember that it’s not just the tire that matters, it’s also the rim width, and that’s the other big trend that we’re seeing is rims used to be super narrow as well, so now as rims get wider, the tires get wider. When we designed the Red Crown barrel wheels, we actually designed that around the Continental GP 5000 tire. We said, “If we believe that this is the all-around best or fastest tire for triathletes right now – meaning puncture protection, rolling resistance, aerodynamics – then we want to build the fastest rim off of this tire.” So that’s what we did. We came up with several different designs, stuck it on that one tire, and said “go for it!” Now we're already exploring the relationship between 28’s and even wider rims, and I’d say for some athletes it definitely makes a difference. The slower you go, the less aerodynamics has a role in this, so wider tires and wider rims make a lot of sense. But there is a point where the returns all vanish. You could just think about it with your head and say, “Well, what if I put smooth fat bike tires on, would that be the fastest then? Those are even wider, right?” No, it’s going to be slower, those are aerodynamically going to be a huge disadvantage. But you're also going to have a lot more area on the ground at any one time, even smooth gravel tires are slower than smooth road tires. So there is a point of no returns, and you're just trying to find that inflection point of where aerodynamics and rolling resistance and impedance, if we use Josh Poertner’s term, intersect to find an optimal tire for the conditions.

Andrew: If you’re listening to this, and you really want to nerd out on any one of these questions, go find the Marginal Gains podcast and queue up a couple of episodes, because they get hella sciencey. You might find it interesting, it might go over your head, but I do want to plug that. Since you mentioned him, TJ, I know you have a good relationship with Josh. Number two, I thought this was really interesting, when I got my Dimond bike – the bike is very impressive, but I knew the bike was impressive. The thing I didn’t expect was just how blown away I would be with the wheelset. I was like, “Oh my gosh.” When you read about modern wheelsets, and you read about things going wider, and you read about them going wider for all of these reasons, for the first time I was like, “I have a modern wheelset in these Red Crown wheels.” These things are incredible. So saying all that to get into my next question – we are at an astounding almost-200 episodes into the TriDot podcast that are out there in the wild, and if I had a dollar for every time Jeff Raines told me that a question I asked was the million dollar question, I wouldn’t need this job as a podcaster. But for the first time, I am declaring a question to be the “million dollar question”. TJ, Jeff, based on what wheelset you have, what the width is, what tire you’re running, all of that jazz, how can an athlete at home look at their setup and determine what PSI they need to run on their bike? TJ, start us off here.

TJ: Jeff, I need a drum roll here, because I’m going to hit this one out of the park right now.

Jeff: Badabadabadabadabada!

TJ: Perfect, all right, here we go! So if you go to silca.cc, that is Josh Poertner’s website. He has a Silca Pro Tire Pressure calculator, and it is one of the coolest tools out there. Josh spent years and years developing this, and when he first released it, it was top-secret. You had to give him some information to get this stuff out of there. But now it’s really cool, you go into this calculator, you put in your total system weight. This is the weight of the rider, plus the bike, plus any gear you have. For a triathlete, sometimes this is really hard to do, because you’re talking about you, your bike, all your hydration, your nutrition, stuff you have on it, and you’re probably soaking wet, so it’s probably going to be pretty high, higher than the number you want to see. I usually use somewhere around 192 pounds, and keep in mind I race at like 163, so I’m putting 29 pounds onto my bike. My bike doesn’t weigh anywhere close to that, but I’ve got all this nutrition and other stuff, so I’ll put 192 pounds on there. Then you select your surface – so, track, wood indoors like Bradley Wiggins’ efforts on there, or what I usually do is warm pavement with some cracks, because that’s the reality of what we’re riding. Then your measured tire width – and this is a cool thing, Josh has this method. There’s a guide in here, but he wants you to take a paperclip, wrap the wire paper clip around the tire, and then measure the width of that paper clip to get the measurement of the width of your tire. This is NOT the tire width on the label, because the same tire on a Red Crown barrel that’s 28 millimeters wide, versus Zipp 858 NSW that’s 20 millimeters wide, the tire width is not going to be the same. We want to know the actual width, and that’s where Josh has this little guide in here for you to use that. The tire diameter, which for most people is 700c or 29 inches, and the tire type – high performance tire, tubeless or a latex tube, mid-range butyl tube, or puncture resistance like Andy Potts riding his GatorSkins in Kona one year. We don’t recommend that. Select your tire, and then your average speed. If you’re a pro triathlete, you’re going to put pro tour speed on there, and if you’re not, you’re going to select the right speed for you. Then your weight distribution – first one is 50/50, roughly 50% on the back, 50% on the front, which means you’re a triathlete. Then you click “calculate”. If I have a 23 millimeter measured tire width, which is what it is if I put a 23 on the front of a Red Crown barrel, that’s giving me 108 PSI. But if I bump that all the way up and say I’m going to run a 28 at that same weight, it’s going to give me a PSI of 79.5. So you can see how important it is to measure the actual width of your tire. So the 25 is going to dump me down to 95, and then let’s say I did the total extreme and I went for 20 millimeter tires, that’s going to put my rated PSI all the way up to 134. So when I talked about Bradley Wiggins riding the hour world record, on a smooth surface on these high-PSI narrow tires, that’s why you get this, and you can see for yourself what tire pressure you should run at. I love this calculator, I refer people to it all the time. Josh is a very brilliant guy, and this is the best place to start when you’re thinking of how much pressure you should put in your tires.

Andrew: No reason to drive ourselves wild trying to reinvent the wheel when somebody like Josh, who studies this, has produced a resource for us all to use. I want people to catch, TJ, when you’re talking about the importance of measuring the tire width on the wheel you’re running. That is what we’re alluding to, that there is a relationship between however wide, whatever the exact shape of that wheel is, when you mount the tire onto it. Those two surfaces have to meet, and whatever shape, whatever width your wheel is, will have implications for the shape and the width that your tire ends up being once actually mounted to the wheel, and that’s why it’s important to measure. It might be different from wheel to wheel, so I do want to note that. Jeff, anything to add here from you? I know you are very competitive at the races, you coach a lot of very competitive athletes who I’m sure have asked you this question millions of times. Is there anything in addition that you would want an athlete to know in addition to the resource TJ just pointed to?

Jeff: I would just throw in that a more comfortable rider is also going to be a faster rider, especially in the long hall. We know that the wider tires, lower PSI can help with the comfort aspect as well, and that has to do with that contact patch that TJ was talking about earlier. That’s the portion of the tire that slightly flattens as it contacts the road, and PSI determines the size of that contact patch. That wider tire has a wider and shorter contact patch than a narrower one, and that creates less rolling resistance, faster and so forth. But whether you have a skinnier tire with a high PSI, or the newer, wider tire with less PSI, there’s a range you can fall in, and that’s what TJ is really honing in on, the exact where you are in that range. But from a super beginner, they’re just like, “I’m going to go ride. In eight minutes I’m going to be on the road riding, and I’m pumping up my tire right now, and on the sidewall of the tire it might say 80 to 120 PSI, or don’t go higher than this max.” So super-simple in layman's terms, where you fall in that range is the “it depends” answer. Million dollar question, and “it depends”. You may want to take into account the road surface, the temperature of that surface of the road, if it is a very technical day, if there is a lot of cornering, or if it is just fast and flat. So if you are, and you know what that range is, you may want to go on the lower end. If it’s going to be super wet, you might want to have a slightly bigger contact patch, even if it’s slightly less aerodynamic or beneficial, but having that better grip on wet roads, or beginners, all those things. So where you fall in that range will depend on the road surface, temperature, if it is going to rain, comfort, and all of those things. If it’s just a fast, flat time trial, you might want to go to the mid to upper end of some of those “when in doubt” ranges.

Andrew: TJ, an interesting thing I want to ask, just from my own personal experience. I started on butyl, then when I learned about latex tubes, I switched to latex tubes, and now obviously I’m running tubeless. When I was on butyl tubes, you can pump up your butyl tubes and go for a ride, and the next day you could probably go for a ride again without even pumping up the tire, because it retains its air so well. When I switched to latex tubes – because they do lose PSI a little faster than a butyl tube, and for somebody who isn’t experienced with that – on a latex tube, even with my bike on the trainer, I was pumping up the front tire every single day to make sure that there was air in there, because overnight it would lose a significant part of its pressure. So as you’re riding, especially half-IRONMN and IRONMN distance where you’re on the road for anywhere from two to eight hours depending on the rider and distance, if you’re running latex, or if you’re running a tubeless setup, do you need to err a few PSI higher than what the PSI recommendation might be, because you know over the course you’re going to lose some PSI? Or are you losing such a marginal amount that that’s not really a factor?

TJ: This is tough, and here’s part of the problem. When Josh Poertner was working at Zipp, and he did this big study in Paris Roubaix on their wheels and tires, they found that the difference from the pumps they were using was as high as 12 PSI off. So if they were shooting for a hundred, sometimes it was six lower than a hundred, sometimes it was six higher, so 94 to 106. Josh has tools for all this stuff that regulate this, and obviously he makes really high-end pumps that do a great job of reading accurately. But for the most part, you might want to go a couple higher as you pump up – but not too much higher, even with the latex tubes – because you’re going to lose some. But if you’re running low on purpose, you’re running low for a reason, you could be in that range where you say, “Hey, I know this is going to work.” Josh Poertner just chimed in here and said he wanted me to remind you that when Bradley Wiggins did his test, he did 300 PSI of argon gas in his tires. I don’t know from Josh right now if it was either 19’s or 20’s, with 300 PSI in his tires with argon gas. That’s the other thing, what’s actually leaking out of that is the CO2, which leaks out a lot faster. So if anybody’s been to Costco to fill their tires up, Costco uses nitrogen to fill your ties, because it leaks a lot less. It’s less permeable, the molecules are much larger, so they don’t escape through. That’s one of the advantages too, if you wanted to use nitrogen or argon in your tubes, you could have a more optimized setup. But if you’re just like most of us and you’re pumping it up – yeah, sure, pump it just a tiny bit over, pop the valve off, because you might lose some pressure there, and then go out and ride. So for the question, “What pressure should I use?” I’m going to give the answer, “For most people, let’s target 80.” If you’re heavier, maybe a little more, if you’re lighter, maybe a little less. Josh Poertner likes to ride his bike around 70 PSI. I think you’ll find that the comfort side of it is really important, and for the average person out there, you’re going to find that comfort around 80.

Andrew: I am curious to ask this, TJ. As you’re mentioning that you literally built your wheels around a tire that is widely known to be one of the best performing tires out there – as you’re talking about that, the room I’m sitting in right now, my Dimond bike is right in front of me – so you said that, and I looked over, and sure enough, when you sent that to me, you sent it with Continental 5000 tires. So I’m like, “Aw, sweet! I have the tire that is literally made to go on my wheelset!” That’s perfect for me, good to know, I’m always going to buy that tire now. But for a lot of people who hadn’t bought a Red Crown wheelset on a Dimond bike, whatever they’re running, they go to their local bike shop, they know it’s time to get a new tire put on their bike. How can we determine what tire we should be buying? There’s always different sizes, different treads, different slickness, different protection levels, different widths and all of that. So for our folks listening, how do we look at the shelf and determine what tire is best for us?

TJ: For the average person, I think you’re looking for this combination of speed, comfort, aerodynamics, and puncture protection. And I think the higher up you race, the more risk you’re trying to take, so you’re trying to optimize your aerodynamics and care less about the puncture protection. We settled on the GP5000 because we think it does the best of marrying all those things for total system optimization. But are there tires that roll faster than that? Yes. Are there tires that have better puncture protection? Yes. So you have to determine what’s important to you, but if you’re like what we think most triathletes are like, that’s the right tire. If you’re going to your bike shop, sometimes it’s what they have in stock, but also sometimes it’s what you want to use. We talked about training wheels versus race wheels. I prefer to train on one set of wheels, but have new tires for race day. It’s a little bit of a mess with the tubeless, but I like race tires. Still right now, I’m going to jump on a race here in a few weeks, and I’m going to put GP5000s on to race on. Could I put a faster tire on? Yes I could, but again, then you run the risk of having a puncture, they’re just not as durable. Tubeless solves a lot of that, but it doesn’t solve everything. There’s no one right tire for anybody. There are lots of fast tires and combinations of what you need, but our personal preference happens to be the Continental GP5000.

Andrew: Yup, and that is on my bike that I’m looking at right now, so glad to hear that. Jeff Raines, as you dialog with your coached athletes, they all have different model bikes, different year bikes, different technology in their wheelsets, what do you tell them in terms of helping them get the best tire for the occasion for their bike?

Jeff: A big thing that I talk about with my athletes, and something that I have noticed, is that most athletes are worried or concerned that they may get a flat. So choosing that tire that is a little bit sturdier can help. With tubeless, you don’t have to worry about pinch flats, less air pressure is required, and better shock absorption on rough terrain. The sealant inside, stuff like that helps with those minor punctures. If they’re worried a little bit more about something like that, we might go to a little bit more sturdier tubeless-type tire. But a big thing I say is keep the PSI in the recommended ranges. Pinch flats are what you see a lot in these long-course races, especially with beginner riders. Their head is down, their mind can tend to drift a little bit when they’re out there for hours and hours. So hitting a pothole or a rock, when that tire compresses and pinches the tube against the wheel rim, pinch flats are something that I see a lot. So I’m always an advocate of a little bit more of a sturdier tire rather than that sleeker, lighter type one, just for the day-to-day. I don’t want to get too much into flat tire prevention on this, but a lot of the butyl tubes will have talcum powder on there, and I get the question a lot of, “Hey, this tube is not slimy, it’s kind of powdery, what is that?” That just reduces the chafing on the surface of that tube, and it keeps the tire and tube from sticking together, sticking to each other and causing flats as well. So some athletes, if they run butyl, I have them pick a tire that’s sturdier, but also have been known to have their own bag of talcum powder at home that they dip new butyl tubes into.

Andrew: Ah, interesting. It very much goes in line with what TJ was talking about with the more aggressive rider you are, the more you’re hoping to eke everything you can out of your performance on the day. If you’re gunning for a podium, a pro card, a Kona slot, you’re trying to be in the mix in your age group in whatever race it is, maybe you go for a more aggressive, less puncture-resistant wheel. If you're doing IRONMN or half-IRONMN and you want to make sure you're not the athlete on the side of the road fixing a flat, maybe opt for something that might be a little bit slower, but a lot more puncture resistant. That obviously saves you time in the long run if you don’t end up with a puncture. Good stuff from both of you here.

I’m going to shut it down today with a little banter with TJ. If you haven’t checked the TriDot Triathlon Show on YouTube, we’re out there doing video content, having a lot of fun with it, trying to get our coaches on camera talking swim, bike, and run. And big thanks to TJ, you came on episode one of the TriDot Triathlon Show, and we did a fun segment with you where you counted down your top five favorite paint schemes you’ve ever done on Dimond bikes. Dimond bikes famously does custom paint jobs for their customers. As Jeff and I already mentioned, we run a custom TriDot paint scheme on our Dimond Marquises. How difficult was that for you, out of the thousands of bikes you’ve sold, to pick your favorite five?

TJ: Man, it’s excruciatingly painful to have to do that! You’re talking about thousands-plus bikes, and years and years of doing custom paint. It’s trying to highlight everything, because we want to get some of the airbrushing there, some of the stuff that our local painter’s doing here, like cool fades and contrasting colors, things that are throwbacks, and things that are modern. So it was super hard to do, and I’m sure if you ask me to do it again in another five years, I’d come up with a whole different – and my headspace would just be different about what I’m thinking about at the time. It’s cool, and that’s my challenge if you’re listening right now – make a paint scheme that gets in the top five. Do it for me, so in five years we can revisit this, and you’re in that.

Andrew: I just made TriDot photographer Scott Flathouse pick his top five favorite photos he’s ever taken at the races, and his library is 420,000 photos. So he kind of said the same thing, he was like, “Dude, this was so hard.” But he did it, and it was really interesting to watch that on the channel. If you haven’t heard, if you haven’t listened to any of the podcast ad reads where I talk about our relationship with Dimond, we have a really cool partnership between TriDot and Dimond. We believe fully in what TJ is building, with just excellent, high-end race bikes. If you want to go fast, get on a Dimond bike. Here at TriDot training, we are trying to help you develop your engine, and then TJ can sell you a Ferrari of triathlon race bikes. If you are a listener who does not use TriDot training as your training platform, you can buy a Dimond bike through TJ, and as an extra thrown in there, you will get six months of free TriDot triathlon training alongside the purchase of your Dimond bike. That’s a really cool value add that we’re doing together. If you are a current TriDot athlete and you’re interested in a Dimond bike, you will get a pretty sizable TriDot store credit to shop online. You can buy TriDot gear, Garmin stuff, all sorts of things through the TriDot store. So if you’re listening and you’re interested in that, reach out to TJ or myself, we’re happy to give you more information there. TJ, anything else you want to add as I try to organically talk about that?

TJ: No, that’s great. I think that’s awesome. I love the relationship with TriDot. I’ve got great coaches riding bikes, spreading the word about great bikes, so if you want to join our loyal following of customers, I’d love to have you!

Cool down theme: Great set everyone! Let’s cool down.

Vanessa Ronksley: Welcome to the cooldown! I’m Vanessa, your Average Triathlete with Elite-Level Enthusiasm! For today’s Coach Cooldown Tip, I am joined by TriDot coach Jarryd Irvine who usually lives in South Africa, but is currently in Muscat, Oman running the water skills program at Cheltenham International School. Jarryd is an avid trail runner, and has expertise in swimming and strength training. He has been coaching triathlon for four years with Infinitude Multisport Coaching, and with TriDot as an athlete and a coach since 2020. And you know what? He LOVES TriDot! But most importantly, Jarryd is passionate about helping athletes achieve success that they didn’t even think was possible for them. He specializes in coaching athletes on swim technique, biomechanics, trail running, and integrating holistic wellness. Something that most people don’t know about Jarryd is that he is very musical. He actually taught himself to play guitar, which eventually led him to being a member of a thrash metal band and a couple of rock bands. He now says that he just messes around in a garage band. Jarryd, welcome to the cooldown!

Jarryd Irvin: Thanks much, good to be here!

Vanessa: You know what’s funny, Jarryd, is I actually think you would get along really well with my husband, because he’s a drummer, he taught himself to play guitar, he loves heavy metal, and he plays around with all kinds of music technology. I think you guys would hit it off if you had a little jam session or something. But what we’re here for is a tip. What tip do you have for us today?

Jarryd: My tip for today is basically that to swim fast, you have to swim slow. Most people have a fast and a slow gear, and not really anything in between. So I like teaching them how to manage their energy systems, not just fight for survival.

Vanessa: I’ve actually heard that before about being a “one-pace wonder”, because I know that swimming or biking or running at one pace is not very beneficial. So I actually tried this today, because I knew this was going to be your tip. I tried swimming a hundred meters as slow as I possibly could, and it was so hard! I thought I was going to sink so many times! So I’m wondering, how slow are you actually talking? Is there a goal, like your Zone 2 pace plus ten seconds per hundred meter, or plus 20 seconds?

Jarryd: The challenge comes in where you’re basically swimming, you can do 25 meters, or 50 or 100 meters as slow as possible, and it’s literally as slow as you can go without breaking your stroke. It doesn’t have to be any particular zone, and it’s quite a fun challenge, because it teaches you a lot about how to keep your body afloat, and do the motion, without actually propelling yourself forward. So you're doing the technique, but not really creating forward movement, if that makes sense?

Vanessa: Yeah. So does this expose some kind of weakness in a certain part of your stroke, if you’re struggling to swim that slowly?

Jarryd: Yeah, so the first thing that it would highlight is your body balance. You have a center of gravity and a center of buoyancy in the water. Basically, if you can imagine a dot in line with your hips, and your center of buoyancy will be a dot in line with your shoulders, and that should balance you out to help you keep your legs up, because most people will kick to keep their legs up, and not engage their core to keep their legs up.

Vanessa: Oh my gosh, that sounds so complicated! I can’t wait to try it when I hop in the pool, to try and work on that body balance. Are you talking about lateral rolling from one side to the other, making sure that you're balanced in that plane?

Jarryd: No, I’m talking about being balanced – if you had to look at yourself from the side, your hips are basically the middle of a seesaw, and then your legs and your arms and your head are either side of the seesaw. What most people will do, if you have a kickboard, then your kickboard’s sitting on top of the water, and your legs are dragging in the water. So you kick harder to get your legs up. But what I try to teach people is to actually press the board down, so that forces you to activate your core, and then you don’t have to kick upwards to get that propulsion, you have to focus on kicking more down and up.

Vanessa: That’s amazing. I think that you have this really crazy background in swimming that has allowed you to analyze every single piece of information in the body. I think that is absolutely amazing. That’s a great tip!

Jarryd: Just quickly on that – when I was a kid, I couldn’t coordinate my body at all. Basically when my coach started teaching me breaststroke, he was like, “I have no idea where to start with this kid.” He’ll tell you that as well. So coming from that position, I know you can go from that to knowing what your body is doing. I know it’s possible, it just takes years of practice. People hate hearing that, but I think the best thing is, to swim faster, you have to swim slower, and teach yourself all the pieces of the puzzle.

Outro: Thanks for joining us. Make sure to subscribe and share the TriDot podcast with your triathlon crew. For more great tri content and community, connect with us on Facebook, YouTube, and Instagram. Ready to optimize your training? Head to TriDot.com and start your free trial today! TriDot – the obvious and automatic choice for triathlon training.