A Deep Dive on Tires and Pressures

The science behind fast tires has evolved rapidly in recent years, so Trevor Connor and Caley Fretz called in tech writer Kristen Legan to dig into the latest research.

The difference between a fast tire and a slow tire can be ten or more watts. So how should you optimize your tire selection and tire pressure? The science behind fast tires has evolved rapidly in recent years, so Trevor Connor and Caley Fretz called in tech writer Kristen Legan to dig into the latest research.

Episode Transcript



Welcome to Fast Talk developer news podcast. Everything you need to know to run like a pro.



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Trevor Connor  00:35

Welcome back listeners to another episode of Fast Talk. This is Trevor Connor velonews. Coach here with my usual partner Kelly frets. Hey, Trevor. Hey, Kaylee, how you doing?



I’m a little bit sick. Sound gross. I apologize listeners put some put some disinfectant on your earphones today.


Trevor Connor  00:53

I have arrived at velonews to a play going through the office. I’ve been limiting my time here, but we’ll see how it goes. And of course we have with us today since this is a tech conversation. Kristen leagan. Hey, Trevor, thanks for joining us, Krishna.



Good to be here.


Trevor Connor  01:10

So I am doing the introduction today because this might very well be the only contribution I have to make through this entire episode. We are talking about rolling resistance and both Kaylee and Kristen were shaking their heads at the $10 tires I



bought yesterday. Yep.


Trevor Connor  01:29

They look like a garden hose. If you like a garden hose, I like them. You would you would Trevor,


Kristen Legan  01:34

you’re gonna get really strong using those in training?


Trevor Connor  01:36

Yes, I



  1. It’s like, it’s like riding with a parachute.


Trevor Connor  01:40

Because my fenders don’t do that. Right?



You already have.


Trevor Connor  01:46

So anyway, today, we’re actually going to go into something that that has been changing in the world of cycling. We saw this change 1015 years ago. And we’re going through it again, of realizing that what we’ve been riding on might not be providing us the the best rolling resistance. Krishna is really dug into this really understands the science behind both the materials to size, tire pressure, how all these different things affect your rolling resistance on the road. So we’re really excited to have her in here and to talk about this. And like I said, I will probably be sitting back here saying, but my garden hose tires are still better.



So yeah, Trevor’s gonna play the retro grouch as, as he often does, Kristen and I are more tuned into the latest and greatest entire technology. And we should preface this with the fact that we both believe that this is an area where you can actually see quite a lot of improvement. If you believe the science, if you believe the data, we’re talking about increases in efficiency, like wattage, style, efficiency, upwards of sort of six 810 watts between a really good race tire and sort of your average training tire. And that is very significant. Anybody who trades with power knows that you can spend a good portion of a season trying to get eight to 10 watts. So this is something you should definitely be paying attention to. However, that sort of ultimate rolling resistance figure is not the only thing that we want to be paying attention to, that’s probably where I kind of come into the conversation, in terms of real world application of these various tire technologies, you can get the fastest tire in the world. And as Tony Martin learned in the, in the Tour de France a couple years ago, when he double flatted in a time trial, that doesn’t matter if you don’t make it to the finish line. So I think a good place to start Kristin is a 10,000 foot somewhat in depth, but not too in depth discussion of what rolling resistance actually is. Right?


Kristen Legan  03:57

So yeah, we’ve all heard about rolling resistance. And you can kind of think of it in two different ways. There’s two different kind of forces or things working on your rolling resistance. And one of those is your weight, the weight of your body plus the weight of your bike pushing down on the tires. So that plays one role. The other role is the impedance from the road. So you know, think about the road vibrations from a, from a bumpy road, you’re going to lose energy in the in your movement forward when you hit those bumps.



And that’s an important concept that we’re going to have to return to later because as we start to start discussing things like studies and data, it is important to differentiate between studies done on something like a smooth roller, where the impedance is going to be close to zero, and sort of a more road like surface. Exactly.


Trevor Connor  04:51

So good example that from the old days. I’m actually old enough to remember back when people would pump their tires up to 160 psi for a time to think Making them faster and go to races on horses. And there actually is some Yes. Thank you. Wait a minute I raced in Pennsylvania people did go to races on horses. There is some science showing that that higher pressure will make you a little bit faster, it’s very marginal that make it a little bit faster. But you would get bounced over the road so much, you get so little shock absorption from the tires, that you would see riders actually their upper bodies would get tired, their arms would get tired, and it would ultimately hurt their performance because they couldn’t hold a time to our opposition with that sort of tire pressure.


Kristen Legan  05:39

Okay. But it also, you know, besides making you tired and uncomfortable, it actually slows you down when you get to a certain point. And I think somebody one studies calling it the break point pressure. And that’s where the graph shows, the higher the pressure you’re getting, there’s a point at which as you continue to put more pressure in there, you’re going to get slower. So for a while, you’re going to have less rolling resistance with higher pressure. But then at a point in time, depending on the surface of the road, you will then start losing



speed, speed, velocity,



you’ll you’ll



Yeah. Kristen, before we go too far down this, these other roads, I want to step back and get a let’s get a complete definition of resistance. You talked about impedance and how weight factors into this equation. But what exactly we talking about here.


Kristen Legan  06:31

So let’s say that you’re riding down the road to and you stop pedaling, and you keep coasting taking all of the mechanical resistance out of there from your bike. Exactly. So what’s pulled what’s making you slow down. So there’s two factors, there’s errors distance, wind resistance that’s pushing against your body and your bike, that’s going to help slow you down. But then there’s also rolling resistance, it’s the forces that are working against you. So without those, you would just keep going along in a vacuum, you know, you would just keep rolling along with nothing resisting your forward movement. So So rolling resistant has to do with your contact with the ground that is stopping you or slowing you down.



And it’s essentially a function of how much impedance you are encountering and your weight. Is that correct?


Kristen Legan  07:16

Right? Yeah, it all works together in terms of tire pressure, your contact patch with the ground and how that’s effectively pulling you backwards.


Trevor Connor  07:26

So how much of it is aerodynamics? And how much of it is rolling resistance


Kristen Legan  07:30

depends on your speed. aerodynamics are always dependent on how fast you’re going. I read somewhere that at around 10 miles an hour with a normal position bike position, that’s where you’re rolling resistance could actually cause a bigger change than aerodynamics. I don’t know if that’s true or not, but something I read



probably somewhat dependent on position and things like that. Yeah, no, that makes sense. So yeah, I’ve heard that sort of regular racing sort of speeds, you’re looking at probably 70 80% of your resistance is, is wind is the air. And sort of the remaining most of the remaining resistance is, is rolling resistance. There is some you know, there’s bearings and chain and things like that, but it makes up a relatively small portion of of your total resistance. And again, this is this is essentially everything that you have to overcome, to ride faster. So this is the smaller we can make these numbers, the faster you can go, it’s pretty simple math once you once you really boil it down. And that’s why we spent a lot of time talking about aerodynamics, it’s why we spend so much time testing things in the wind tunnel, we should be thinking about rolling resistance, maybe not quite as much, but almost as much. So we keep using the word ground, you’ve used the word ground a number of times already in this podcast. That brings me to kind of the next next section that we want to talk about, which is considering your use essentially considering where you’re going to be writing what you’re going to be writing on. And to that end, kind of the differences between the real world and a lab setting.


Kristen Legan  09:06

Right? So yeah, I think in order to think about the types of roads that we’re writing, whether it’s a gravel road or just a pavement with cracks in it, that kind of thing, let’s stake take a step back and just look at in the lab, a perfect situation where it’s a perfectly smooth surface or close to that. And then we can kind of take take a step back and look at the other types of roads. So in a lab situation, we find that in most in most cases, higher pressure is going to be faster, it’s going to reduce the rolling resistance. It’s not a linear relationship. At first, you know, around 5060 psi, you’re gonna see a huge jump. And then gradually as you get up into like 171 ad it’s going to be smaller and smaller improvements in your rolling resistance per psi. So yeah, exactly.


Trevor Connor  09:57

Yeah, I’m looking at this unfortunate study here, where they send Subjects out on the road at 181 psi.



And they survived. And they survived. Well done well done riders. So So what is the ideal is have we determined sort of an ideal type of tire and pressure and width for in that lab setting. So like assuming that the road that you’re riding on is smooth as glass, what is the ideal?


Kristen Legan  10:22

Well, I mean, you can break it, there’s so many factors that go into that, right like the construction of the tire that affects your rolling resistance. So, but as you say, also the width of the tire. So people are doing more and more studies recently on wider tires, because we’re getting this changeover to wider rims, tires are getting wider, everything’s happening and getting wider. So they’ve done some studies and actually found that wider tires are, they produce less rolling resistance at the same pressure. And that’s one thing that we have to remember when we’re comparing all of these different tire widths and tire types, everything has to be on the same rim at the same pressure. And so yeah, so if you are in a lab, it’s perfectly smooth situation, a wider tire is going to be faster than a narrower tire.


Trevor Connor  11:08

So before we started recording, Trevor, you were talking about tire footprint, which I think might explain why that is the case. So this is a way it was explained to me that really helped me to understand the physics of cycling tires. So in the literature, they talk about the footprint, which is the part of the tire that makes contact with the ground. And one of the things that’s very enlightening to me is your footprint tends to be about the same size. So if you’re on a 28 c tire or a 17 c tire, you’re still going to have relatively the same size footprint, which means that if you are on that narrower tire, you actually have to deform the tire more to get that contact area on the ground, because it’s longer essentially longer. It’s wider. Yeah. Also the tire, the tire is very narrow, right, so it has to deform more to spread out where 28 c tire really doesn’t have to spread out that much at all. bicycle tires are not perfectly elastic. So for them to deform, you’re actually going to lose some energy. And that’s called history says. So back in the old days, when I was getting into cycling, you saw a lot of people time trawling on those 17 C and 19. c tires thinking, well, that’s really going to reduce my rolling resistance. And it was actually the exact opposite. And that’s why we all jump back up to, to the 23 c tires, because we discovered Well, you get less deformation, you’re losing less energy and rolling resistance. So they’re actually faster tires. And what you’re seeing now again, is they’re saying the same thing of, well, actually 25 C is same sort of thing, less deformation.


Kristen Legan  12:47

And I think we can just keep getting wider and wider until a point where aerodynamics do start to come in and play a role. And so I think that in this podcast, we’re talking about wide tires being 2528. Maybe but but as you go kind of beyond that, I think there hasn’t been much research into exactly when is that breakpoint when you lose your resist rolling resistance advantage. And you you because of aerodynamics,



I had always heard that, that the width issue that the tire width issue was kind of a bell curve, too. So you correct me if I’m wrong here. But there is a point at which you know, you’re going to get a wide enough tire that is no longer decreasing your rolling resistance. I mean, anyone who’s ever written a fat bike is pretty sure about that one. And just sort of, you know, anecdotally, every time I put 32 millimeter tires on my bike, even if they’re slicks that they don’t roll as fast as a 25, or 28. But so where is that point? I guess, is my question. Well,


Kristen Legan  13:43

my question is, are you running those 30 mil tires at the same pressure as your 2528? Because that that’s a big mistake that we all make is that we think, Oh, no, you know, it’s something that when you actually sit down and look at the math, and you look at the graphs, and you’re going, of course, that makes sense. But when we go out on the roads, we’re not thinking like that, and so



I said that just so you could correct me. Yeah, yeah. Yeah. That’s the only reason I said, No, actually, you’re right. I hadn’t thought about that. So yeah, when I run when I run 30, or 32 millimeter tires, I run them at like 45 psi, which I guess if I ran my 20, fives at 45 psi, they’d be a little bit slower as well. So I guess that makes sense. It nonetheless, is there a point at which at which it makes sense to go with a smaller tire? I mean, we’re talking about bike racing here, we’re talking about riding as quickly as possible. At what width are we talking about? Where does that where’s that curb start to fall off in terms of particularly when we start to look at aerodynamics, where we’re actually riding a slower tire, even if it is maybe slightly lower rolling resistance?


Kristen Legan  14:47

I don’t know the answer to that. Maybe some of our listeners would know, I would say it’s going to depend on your bike, what it can actually fit and the rim options out there. So another factor Another factor that comes into this is the the tire rim interface. And so if you have some skinny rims with these giant tires like blobbing out over the edges, that’s not going to be fast aerodynamically. So you have to find the right combination. And there’s no great answer out there. I’ve asked a couple of times engineers from the industry and nobody has a you know, real easy answer for me, one person said, the 105% rule, so your your rims should be 105% of the width of your tire,



you never wear out or maybe it’s the other way around, hold on.


Trevor Connor  15:34

Just thinking out loud, when I said your your footprint is always the same size, that’s to a degree, you put a 17 c tire on your bike, you pump it up to 200 psi, you’re gonna have a very small footprint, you’re also going to crash first corner you go around, likewise, you put a 32 c tire on your bike, and and only pump it up to 30 psi, you’re going to actually have a very large footprint, and you’re probably going to to get more rolling resistance from that you’re probably going to have some some frictional factors play in. I also wonder if as you get to as you said, as you get that wider and wider tire, you’re going to have aerodynamic issues. And you’re probably also going to have some inertial issues because the further out you get on the wheel, the more inertia is a factor. If you have a big, wide, heavy tire all the way out the end of the wheel, it’s gonna be hard to turn that wheel around. Yeah, that’s


Kristen Legan  16:26

actually a really good point I hadn’t even thought about, you know, we do rotational inertia testing here at Melanie’s. And putting bigger tires with more weight on the outside of the wheel is going to slow that acceleration and deceleration down.



So width if we’re talking bike racing here, I mean, if we look at the pros, they’ve obviously done a lot of research in this. In general, we’re seeing something in the 25 millimeter range from from pretty much every team and that changed about four or five years ago. I mean, I remember I was covering bike racing when it happened so that I hadn’t been doing that for that long. I remember when when basically the entire peloton went from 23 to 25 over the course of one summer, and that was largely pushed by Shimano actually who came out with with some new wheels and at the time, they were sponsoring like a third of the pro peloton. And they said essentially, we’ve done all the testing 25 millimeter tire is faster on our wheels, and so everyone could switch to the same time.


Kristen Legan  17:24

Remember that why wider wheels are heavier. So the pro peloton is not gonna put on bigger tires that they you know, if it’s a small gain, they’re going to get in rolling resistance, but it’s going to be 15 grams heavier, they’re not going to go for it.



The only exceptions that I’ve seen to that sort of 2525 millimeter rule. Other than you know, I’ve seen teams go 2426 that’s sort of neither here nor there. It’s obviously races like Pirate Bay, where riders are on 28 to 30 twos generally, and they’re they’re trending bigger and bigger and bigger. And the other exception is time trials where we’re seeing riders run something like a 24 on the front, and a 26 on the rear. And that comes back to the aerodynamic question because front wheel hits the wind rear wheel sort of tucked into the bike. So you can run the 26, which actually has lower rolling resistance than the 24. Without the aerodynamic penalty.


Trevor Connor  18:18

We actually spoke to Chris you at the specialized wind tunnel about that. And he said, for a time trial bike, the best balance between rolling resistance and aerodynamics, he was suggesting 23 C on the front, and then the 25 on the back.



Yeah, so similar sort of situation. I think that specialize doesn’t make 23 and 25. So it’s interesting that he said that they make 20 fours and 20 sixes. Which might be why when I had a similar conversation with I think it might have actually been him with Chris, he gave me the 2426 numbers. I’ve also seen that in person walking around the pits, lots of probate cases, you know, taking a look at what tires they’re running. They also tend to run clinchers in time trails. But that is a conversation that we can we can maybe leave for a little bit later.


Kristen Legan  19:06

So Kaylee, you brought up a good point about the about Perry rebate and how you’re seeing writers use bigger tires in those situations. And I think that brings us back to kind of the real world situation. So So while we talked about the lab being higher pressures almost always going to be better till you can’t really go any breakpoint. Yeah, when you get on to, you know, broken asphalt or you’re on your car on the cobbles. That breakpoint actually is at a lower pressure. So the harsher the pavement, the lower that breakpoint pressure where you start adding rolling resistance with more pressure. So you can kind of think about it, you know, with the same tire with the same, you know, on the same rims, the worse the pavement the lower the pressure you want to go. I think that’s something we’ve all kind of grasped in a way, but it’s just interesting to see some of the graphs that have come out of this and it makes you want to really Go a little bit under that breakpoint, then try and push it because it drastically it goes up very quickly, right,



because the data suggests that as soon as you cross over that point, you’re really really harming your your rolling resistance. And anybody who is who has been on a smooth road with a lot of pressure and then jumped on some chip seal knows exactly what that feels like it feels really, really, really awful. It seems like a given that you would drop pressure for rough roads. However, it hasn’t always been. I mean, I remember even a couple years ago, when when the SCA tele ski team was still around, they were sort of notorious for the Spanish in particular, for some reason, I don’t know why I’ve heard this from multiple mechanics. I’ve seen it in person, the Spanish in particular love their high tire pressures. And then How surprising the carrots as we used to call them, they used to tell you skinny guys used to also crash all the time. It’s not necessarily a given, I think, but it is an important point that you do have to after you figured out what size tires you want, you have to really pay attention and match pressure to, to the situation that you’re that you’re encountering. So let’s talk more about pressure. We’ve gone into this a little bit. I when I wrote pepper Bay, early this year, I was running I think 28 millimeter tires, they’re on a wide rims they stretched out, they’re probably measuring closer to 30. And I ran 56 on the front and 62 on the rear. And granted, I weigh 145 pounds, and I ride pretty light because I’m a mountain biker. Never flat it never had an issue definitely hit the rim a couple times through the arburg. But for the most part that was perfect. As basically as in that kind of situation. It’s as low as I can go without flatting. That was that was what I was trying to do. That’s not necessarily a perfect analog for regular road racing pay raise is its own special, special animal. So if we’re talking again about this sort of 25 millimeter tire standard, what kind of pressures are should racers be looking at for their their average, average weekend criterium or a weekend road race?


Kristen Legan  22:12

Well, I think why Yeah. 327? No, you may you know, you you mentioned how much you weigh. And I think that plays a really big role in it. You know, it’s hard to say for for each person what their pressure should be. It should be a you know, it’s a personal number that you have to figure out. Kaylee, we’re pretty similar in height and weight. And I’d say for you, I would, I mean, I’m no expert, but I would say in that 100 205 range on 20. fives on good surface. So that was actually a little bit surprising to me. When I was reading some of the data, I thought all of these numbers would be lower. I was expecting us to be like, wow, we should all be running at psi, because it’s going to help with the impedance.



That does seem to be the sort of the the popular thing these days is to run lower and lower and lower. But that’s not necessarily the fastest, right?


Kristen Legan  23:05

Yeah, I think it’s still kind of that a little bit over 100 psi for a you know, 150 pound person on on your typical, pretty smooth asphalt. It doesn’t have to be brand new. But if you’re hitting some chip seal, or if you’re hitting stuff that’s really cracked and bumpy, definitely drop it. And I’d say into dirt sections. Yeah, I mean, once you get into dirt, I would say don’t use 25. That’s a use 28. Go to 85. At what did you erase folder? Ruby? No, you



were I was that actual Ruby?


Kristen Legan  23:43

Yeah. So I think I was talking to a couple people who wrote, you know, we have some pretty smooth dirt roads out here. But they’re still dirt. And so I think that the the normal pressure around here is in the 80s. You know, low 80s for 28.


Trevor Connor  23:57

I gotta interject for one second, you said that you’re not an expert on this. You’re tech editor for Villa news, you’ve actually done testing on all this sort of stuff. And you’re a professional cyclist, if you’re not an expert, who is


Kristen Legan  24:12

the engineers creating all these products



for the people that we talk to? Yeah, the nice thing about being a reporter is you don’t actually have to know anything. We’ve just talked to the people that do. That’s the that’s the sneaky part of our job. And then we get to tell everybody and seem really smart,


Kristen Legan  24:26

and hopefully get it right. We’re gonna get some emails this time around. But this is a really complicated idea. And there’s so many factors that go into tire creation, rolling resistance, aerodynamics, weight, types of materials, use TPI, all of this so like, like all good questions. There’s no easy answers to this and it really comes down to figuring out what your goals for the race are, you know, is it strictly just I want to go as fast as I possibly can? Do you want to be able to walk after the race, or long ride or whatever you’re doing comfort comes into play there. And then another thing that we you know, I think we’ve talked a little bit about is with the construction of the tires, your grip on the road plays a big role in that and also with because wider tires or tires that have a good grip on the road are going to allow you to go through corners faster they’re going to allow you to kind of corner and maneuver through the peloton easier with you know, not feeling like you’re just gonna slide out so so there’s a whole bunch of stuff that goes into play to make you a faster cyclist. We’ve been just thinking about throwing resistance kind of in its own in a vacuum. Yeah, exactly.


Trevor Connor  25:35

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Let’s talk a little bit more about construction. And this we can both talk about materials used the type of construction use the type of sidewalls the type of you know, rubber used. And then also the sort of the broader question is the old the old clincher versus tubular debate which we have. We’ve had many many times before. We discussed clinches versus tubulars in the past, particularly relating to things like do you need to be theirs to race your bicycle? And the answer that is a definite No. Nonetheless, they’re very, very different construction methods and I and they do tubular versus clincher definitely affects the rolling resistance of the end product. So let’s talk about I so a couple years ago, we started getting this sort of spate of cotton sidewall race tires, specialized make some they kept telling us they were the fastest ones ever. Victoria now makes a very nice one. I’m a huge fan. They’re not particularly durable, either from specialist or from Victoria. But man do they feel nice they ride so so nice, nice. I have no idea what that’s fast. They say it’s fast. The data says it’s fast, but I just know that they ride really lovely at my chosen pressure. So over the last couple years we’ve come I’ve come to expect anyway that these these cotton sidewall tires are the fastest tires in the world. We’ve been told this by by multiple manufacturers, it’s been confirmed in our own tire testing was confirmed a couple years ago. However, even in the last sort of 18 months, things have changed once again. So Ben Delaney, good friend of all of ours actually a former velonews guy we love Ben now works for bike radar and bike radar did a big did a big tire test recently with the wheel energy guys up in up in Northern Europe. This is a company that does independent tire testing. They’ve done it for us they’ve done it for again for bike radar, they’ve done it for for manufacturers. Anyway, Ben sent, we let him do his whole big pile of tires. And the results that came back were interesting to me because again, it was kind of expecting to see things like the specialized turbo Cotton’s and Vittoria, his own cotton sidewall tires up at the top. That is not what happened. Schwalbe the pro one tubeless were the fastest, followed by Michelin power competition, followed by zipp tangente speed 28 millimeter. None of those are cotton sidewall tires. in fourth place was the specialized s works turbo tubeless.


Kristen Legan  28:25

That was on this just the smooth drum though, because those got bumped down once they did the the rough drums of the more real world situation true. So



there’s two sets of data here, there’s a smooth drum and a rough drum. So yeah, as soon as you get onto the rough drum, then the the top three actually remain the same. But that specialized gets bumped down a Bontrager tire the four gets bumped up. And you know, we’re talking we’re not talking about massive differences here. But so the swaby on this test, the rough drum test is at 29.9 watts at with 50 kilograms on it at 40 kilometers per hour. So it’s a very light rider, particularly a very light rider and bike. But nonetheless, the the the relative diff differences should remain the same. That’s that’s 29.9 watts for the Shelby all the way down to you get down to a Clemente lcV, that’s 36.1 watts, that’s, that’s 6.2 watts. That’s not an insignificant amount of power. Granted, I think any of these tires up in the top 10 are probably going to be a really, really good race tire and you’re not going to feel any difference. But my point stands, which is that I was expecting to see these cotton sidewall tires at the top of the list. And that’s not what happened. We have a tubeless tire at the top of the


Kristen Legan  29:37

list. Well, I’m curious if during this test, all of these tires were run at the exact same pressure to keep everything equal. And so my question is, is that maybe the cotton tire discount and sidewall tires can be run at an at a higher pressure because that that cotton actually makes them a little bit more compliant so you can run at a higher pressure and have the same Feel in the same, you know, comfort on the road? So that’s my question is, maybe they’re slower at the same pressure, but because you can actually run them the cotton tires at the higher pressure, then they’re actually faster in that way.



I don’t know. That’s some interesting hypothesis. Yeah, yeah, we may have to test this on our own. Not that we don’t trust Ben Delaney. But we may have to do our own pirate tests.



There’s just so many tests.



There’s so many tests to do. So actually. So this was a great test. Like I said, we love Ben, I really, I enjoyed reading through this one, when I came out a couple of the other interesting points, he did a bunch of real world testing as well, he did some, some raw, a bunch of rides up Flagstaff at the same power and some riding down Flagstaff. As he said, he wrote as close to 250 watts as possible in the same position, backpack runs, climb is about 7%. And the real world differences, the differences that he could parse out of that data were negligible, they’re basically nothing. And you know, having written Flagstaff, many, many, many times, I’ll tell you that actually like a six or seven watt difference on on Flagstaff is it’s it’s, it’s, it’s a pretty significant it’s a, it’s a, it’s a 3030 42nd time change over the course of the entire climb. I just know that from writing it myself and seeing my own power data versus my times. So if this lab data is actually going to be implemented in the real world, if this lab data is actually going to apply to the real world, I would expect to have seen sort of similar differences, invents real world testing, I think it’s interesting that we didn’t, which comes back to our earlier point about kind of the real world versus versus the lab world and how, at the end of the day, I think I think this stuff matters, I think that you can definitely optimize, but it’s probably not quite as dramatic as it might seem, at first blush,


Kristen Legan  31:58

I think that there’s so many great tires out there that you know, if you pick any of those top is 10 that been tested, they’re going to produce pretty similar results. And it depends a lot more on your tire setup. So the the pressure you’re running and the wheels, you’re running them on that kind of thing. So while lots of the companies are putting lots and lots of money into developing the best possible tire, there’s always going to be you know, the the best one out there, that’s going to make you the fastest. But I think that the difference between the top tires is going to be small enough that you can really overcome that by just dialing spending the time dialing in your pressures.


Trevor Connor  32:39

If there was one thing we want to get across in this episode is that when it comes to tires, labs might say one thing, but what you’re seeing out in the roads in the races and what the pros could be something different. So we thought it was important to catch up with at least one pro and hear a little bit about what they think about tires and pressures and material and all the things we were talking about today, before we launch into our take homes. So we thought we’d ask Tom squinch his opinion about tires and what he does in races, partially because we think he has a lot to offer. Partially because if you do three podcasts in a row, he gets a prize. So let’s hear what he has to say.



We’re here with Tom’s screech school we teach. You gotta smile. professional cyclist with Cannondale drapac, two time Tour of California stage winner, we want to ask you about tire rolling resistance. And I know that you’re a sponsored athlete. So we’re going to keep this from 10,000 feet just talk in generalities but how much do you guys pay attention to stuff like that to to you know what tires are on your bike, what pressure you’re running the width tire that you’re running? Do you work with mechanics to chat with mechanics about that kind



of thing?



You definitely do. And first of all, it depends on the race or the ride you do. If it’s a training ride, I don’t really much bother about it. I don’t I like to run my tower tires a bit low a bit more rolling resistance just because I feel more comfortable. And the ride is smoother. However, in races, yeah, if it’s a cobblestone race, you definitely run wider tires, even though the rolling resistance is a bit bigger. But mostly now we do run 20 fives and it’s because it gives you enough grip and very low rolling resistance as well as it is arrow because it used to be the thought that very skinny tires or more Aero but someone said that it’s not well, someone tested it. It’s not somebody somebody with a wind tunnel. Yeah, somebody corrected everybody.



Correct anyone?



So Tony fives is the new, new way to go. And there’s definitely teams that do use different tires for time trials. Because that’s where their own resistance really comes in handy. And that’s the biggest thing for in a crit. In a long stage race. There’s so much so many other things that come into play. That rolling resistance is not key. We do pay attention to it. But in time trials, same as being Aero, aerodynamic. It’s as important as that suddenly



a red racer crate you’re more concerned with grip and comfort and puncture resistance. Yeah, things like that. Yeah.



And overall, you would, I would choose a cassette that fits the course then a rolling resistance light to tire. Right.


Trevor Connor  35:39

This also the question I want to ask is, what is our priorities here? I mean, we really been talking about what’s fastest, I’m talking about rolling resistance. There’s a lot of other factors and races. So I’ve mentioned this before, but for example, last year, when I was down at Tobago, which is a very technical race, I was worried about my climbing so I put a for the race bought a tire that was a fortunate 23 C, and it was meant to be a super fast tire but didn’t have the greatest grip. Halfway through race, it started pouring rain, I’m coming down to technical to Santa’s crash, I get hit by a car, I would have preferred to have had a slower tire that gripped a little better.



Carrot, you pulled a huge scale, UCD. Thread, they’re all bask, they’re not listening.


Trevor Connor  36:29

But that’s in the real world. There’s a lot of other factors and what is the priority here? Is it speed and rolling resistance above everything else? Or would you say for most racing, willing to give up a little bit of that to make sure it can corner better? Yeah,



I mean, I think that’s a really unsatisfactorily conclusion. But it is the conclusion nonetheless, I mean, you know, we really can’t, we can put all the numbers and data in front of you that we can possibly find, including stuff, you know, if you go and search on Google velonews, tire test, we’ve done a number of them over the last couple years, we’ve learned a lot from those. That said, we’ve also written all these tires in the real world. And I think we’ve learned more from that. And I think that that is maybe the primary takeaway is that as long as you get a good tire, you know, and just, if you’re worried about speed, just go on and check out whatever the latest tire test is, you know, one of us media outlets is going to do what, at least once a year, most recent is bike radar, we did one like a year, year and a half ago, we’ll probably do another one in the next year. So go and Google and find the latest, pick one of those top 10 tires, pick a brand that you trust, pick one that you hear has good puncture resistance, and just just go with it and and with Yes, we can say pretty definitively if you’re going to race your bike, which should probably be somewhere in the 24 to 28 range, depending on on course and things like that pressure, again, that’s highly dependent on your weight. There’s actually a couple cool calculators out there, Maverick has an app. Now, Victoria has an app, they both take into account your your tire width, and your rim width and your weight and a couple other things. And they’ll actually pump out a pressure that you should be putting your tires at. Those are, those are super handy. And then from that point, you can definitely just go and you can just kind of experiment. I mean, you know, I, I tend to like the feel of a slightly lower pressure. Even if in the back of my head somewhere. The data is telling me I’m losing one and a half watts, I’m okay with that. Because I like the confidence in the downhills. I don’t want to be like Trevor, pull a carrot, run it run into a car and Tobago, I would prefer to have a little bit more, a little bit more grip and things like that. So I guess that’s kind of where we wrap up today. Right? I mean, are there any other that like I said, that’s just a very, this is a limp, take. limp take by some good tires be happy. That’s that’s maybe how you would pressure play with pressure? Yeah, you know,


Trevor Connor  38:57

here’s where I bring in my retro grabbed moment. Yeah. As you said, in racing, I think when you’re talking about one or two watts, you can say that makes a huge difference. I think you have to balance it. And most races, there’s going to be technical moments, you’re gonna have to Santa’s gonna have to get around corners, and you need to factor all that in. And I would personally go with more of an all around tire, which is what I’ve always done that’s I’ve always raced or almost always raised on the Michelin because that’s how I’ve felt about my film. I feel they’re grippy but they’re also fast. There’s probably faster tires, but not as grippy and it just gives me a good in between. But the question I have is what about racing versus training? We don’t care about training.



We only race we don’t train.


Trevor Connor  39:40

I’ve noticed every time I go out with you, it’s a race.


Kristen Legan  39:46

So just to make it clear that most I mean, any of the tires that we’ve tested most of the tires that we’ve tested, recently, have great grip on them. I know Trevor, you had your bad situation in a rainy situation. But I don’t think we have to think, Oh, well, it’s a fast tire. So it’s gonna have no grip, like most of those tires have good grip, it’s more about puncture resistance in weight. And so, you know, you’re you’re, you’re sacrificing a little bit of puncture protection, when you go to these lighter, faster tires. So that’s, I think, the bigger thing versus grip, you know, unless you’re going to be on really wet roads or icy roads, and you need like those all weather tires or something with a lot of grip, there’s the top of the line tires have have the grip you need for racing.



Agreed? Well, my limp take is super limp. And I think that Kristen has some actual takeaways for us here. Other than just go buy some nice tires and be stoked on them. What else? What else? Can people give people a couple things to do? They go back into their garage and start thinking about their own tires and rolling resistance.


Kristen Legan  40:52

Well, I think we basically started talking 2528, depending on who you are, what kind of races you do. 28 are going to be heavier, but they’re also going to allow for a wider range to have pressures to use 20 fives are going to probably be more of your all around race tire, find something that has the grip that you want. So if you are riding in a rainy area, maybe get some tires that have better grip. There’s plenty of like all weather types of tires out there that are still fast rolling, but have a little extra tread on them



continental continental also, yeah, so the Trevor just hung his head. I don’t know why. So I’ve just I’ve noticed this. This is a little sorry to target interject here. But more and more proteins are riding continental. And there’s a like there’s sort of a rumor running around the pro world that contests are the tire to have in the rain, to the point where riders will actually have like another set of wheels with a pair of continental tires, even if that’s not their sponsor, and they throw it on for rainy stages like GC guys will do this. I mentioned what I crashed on.


Kristen Legan  41:59

How old were those tires?





Kristen Legan  42:03

Also, I was you know, I went to the Michelin tire launch last year. And we saw them testing in you know, on a slick track on what track and those were pretty impressive as well. specialized in their grip on compound has been shown in lots of tests. Great nearly Yeah. Great Marine,





Kristen Legan  42:25

So yeah, so there’s a lot of them out there. So for different writing conditions, and then thinking about puncture projection. So do you ride on really crummy roads that have lots of glass and that kind of thing, maybe going for a little bit of a heavier tire that has a slower rolling resistance is going to be better, so that you’re not flattening out of every race,



making it to the finish much faster than not making to the finish? Yes, yes.


Kristen Legan  42:47

And then silca on there, they’ve done a really great job on their blog, Josh portner has, he’s worked for zip, he’s done a lot of stuff in the lab and just really great information on there. They recommend decreasing your tire pressure three to 4% for each millimeter of tire width increase. So if you’re used to riding at 100 psi psi for 25 and you want to go up to 28 then you know drop it to 89% that kind of thing. So



top tip thanks so good. Yeah.


Trevor Connor  43:26

A little insight thing about pros and and tires is it’s like clothing labels. It is fashionable and Pros will latch on to a tire brand and just their loyalty is unbelievable. The people who ride contest they do not want to ride anything else and you’ll see a lot of pros have their brand that’s all the ride and they have brands that they hate I have a personal vendetta against Conde sorry coffee I’m sure it’s based on zero reality very very loyal to Michigan but you talk to pros generally that’s what you’re gonna find the and it’s often not really based on anything except they were in a key race they got a flat tire so it’ll never ride that brand again and they were riding a brand during a good race. Yeah, that’s



pretty much what happened. The pro peloton these days is the Select team Skye recently switched from velo flex, which was not a sponsor, they just bought them all. They actually still buy their copies I don’t know. Anyway, they switch from Bella flex to continental after they had a bunch of rain crashes out of your mind para nice a couple years ago like Richie port went down and a bunch of guys went down. And basically they the riders were like I we hate these tires now and even though Villa flexes are great tires, and that was definitely not the reason why they were falling down. They were falling down because they were cornering at like 60 miles an hour in the rain. Nonetheless, they decided that that Continentals are the tire for rain and like I said the entire propeller honest as decided this regardless of whether it’s true or not one of those classic examples of the pros, some of them pay really close attention to their equipment and some of them just sort Have a go by feel so a lot of going by feel in this particular instance.


Kristen Legan  45:06

Yeah, and I think a lot of tire companies, intermix their production, so whether it’s labeled Conde, you know, what is it really? That’s the big question. And sometimes you can tell by just the looks, but you just really never know. So that’s garbage tape, right?



Yes, the, the Yeah, that’s particularly particularly common at things like paragraph a, we’re like that. three chords, the tires are there are not the tire that has the name like that. They’re not what they say they are basically, most of the Purdue gas and they say all sorts of different things to say Vittoria, and continental and all these things. So definitely not any of those actual tires.


Trevor Connor  45:46

We’re actually not gonna talk about training. For that, I wanted to say,



we don’t have to wait. You’re talking about training. Alright, so if you’re training by those green hoses from us from Home Depot, you can buy them you buy them like 200 feet at a time for like 15 bucks. And you just cut them up and gloom on like, tubulars? No, and they’re great.



Do not do it. Nobody. Listen to Kaylee, please.


Trevor Connor  46:18

Kaylee saying that? Because he knows, I really believe that Trevor wants to do that. If Trevor could do that, he



would totally do it.


Kristen Legan  46:25

training wheels. I mean, it doesn’t matter how fast you go in training, right? I guess. So some cheaper, slower tires are going to be great. But I think in that case, you want durable and tires that have a good puncture resistance, because you just want to be able to use them for a long time and get Mr. toughies.



Or stick another tire inside your tire. Yep, that’s the other option. Cut the beat off an old tire, put it inside your new tire. And it was called the system.


Kristen Legan  46:54

How often do you guys actually take or get flats?



I like hardly ever Yeah, we also live in Boulder where like yeah, there’s you know, the roads are nice. We have bike trails and lanes and we ride in the mountains where the rain washes all of the sharp stuff off. So boulders a special case. I mean, having lived in places where I got a lot more flats, I can say that the Mr. Duffy thing was was was good.


Trevor Connor  47:17

I this winter. I think I went four months without a single flat. I’m not the fastest guy out there because I had the Mr. toughies inside garden hose tires, but I don’t get flats yet in Toronto, and that’s in Toronto, and you’re riding over a lot of crap on the side of the road.



Yes, I go four months out of flat in Boulder But


Kristen Legan  47:39

well, in the winter, I just ride a cross bike so yep. tubeless Yeah, I mean, that’s a whole nother



don’t even go down that route. Oh, goodness. Okay, well, I think that’s a good place to cut it off. Let’s not stop something. We saw a rabbit hole. We decided not to go down it and we’re going to cut it off because I think that’s plenty of talk about rolling resistance and tires. Thank you for listening to Fast Talk. As always, we love your feedback. You can email us at Webb letters at competitor group. com Subscribe to Fast Talk on iTunes, Stitcher, SoundCloud and Google Play. Be sure to leave us a rating and a comment while you’re there. And while you’re there, check out our sister podcast developers podcast, which covers news about the week and cycling and I am also on that one if you just love the sound of my dulcet tones, become a fan of Fast Talk on facebook@facebook.com slash velonews and on twitter@twitter.com slash velonews. Fast talk is a joint production of velonews and Connor coaching. The thoughts and opinions expressed on Fast Talk are those of the individual for Trevor Connor and Kristen Ligon. I’m Kaylee fretts. Thanks for listening.