What Makes Tires Fast?
 

I'm not an Engineer or a Designer so I really don't know what goes into the design and manufacturer of tires but I am curious. We have had a few warmish days here where I live and I have taken advantage of a few of them to get out on my road bike. When I bought the bike the tires were pretty much falling apart. Old, sidewalls flaking off, cuts, scrapes, basically falling apart so I bought new tires and I got the Continental Ultra Sport 3 tires in size 700 x 25mm. I have used several iterations of the Ultra Sport tires over the years as well as the higher priced tires and my experience with Continentals has been mixed. Mostly I have found the Continental tires as a whole to be slow and not responsive as if I was dragging a boat anchor behind me while other tires have felt very lively and fast. When I was racing I bought a set of the Continental GP3000 tires and did not like them at all. They felt slow and sluggish. I pulled them off my bike when I found a set of the no longer made Panracer Stradius Pro tires at my LBS. When I put the Panracer tires on my bike it felt like someone had strapped a rocket motor to the seat tube of my bike. A lot of people say the Vittoria tires are fast and lively but my experience says otherwise. I bought a set of the Diamante Pros in size 700 x 23 and again I did not like them but I did like the Michelin Pro race tires.

There is a lot of talent in this group and some pretty smart people so again I ask, what makes a tire fast and lively? Thanks everyone.

There are 3 things that affect ride quality in tires, from most important to least: Pressure, Tread compound, Casing construction. I think you're greatly over stating the differences you've felt between different tires. I agree there are differences but they're not huge. I'd also say if you bought some high end Vittoria tires your opinion would change.

One thing that has come out in the last 15 years or so is that we are easily fooled by our senses. A hard tire (stiff casing, hard rubber compound, and/or high pressure) feels faster because more high-frequency vibrations are transmitted through the body, but it may not actually be faster.

Fast tires have lots of flex, or compliance, at the tread, courtesy of finely woven, supple casing materials and a thin, flexible tread. Part and parcel to those things are lightweight, so the fastest tires don’t offer much by way of puncture resistance.

And I am of the opinion that tire differences are very noticeable, even extremely so when comparing the cheapest tires to premium performance tires.

​​​cxwrench noted, though, it’s a model issue, not a brand issue, so your Vittoria Diamante are very different to Vittoria’s too tier Corsa.

Generally, look for for high thread-count casings and do read the manufacturers’ descriptions to understand a tire model’s intended application.

The motor.

I believe I definitely feel a difference in the ride quality from one set of tires to another. Tubes also make a difference. Regarding speed, probably not as much difference as one is feeling when riding. Smooth and quiet just feels faster to me. My favorite road set up now is Vittoria Open Pave 27mm with latex tubes. They make for a very supple ride, good flat protection and decent durability. Along with low weight and rolling resistance, and relatively low cost, they are a terrific value, IMO.

Pairing a tire design with the road surface can make a big difference in performance.

The main ingredient that makes a tire fast is the person riding the bike they are mounted on.

Yeah, this even applies to pro riders. That podcast I’ve linked a few times where Jan Heine is talking with Jeff Poeetner is very on point. Poertner runs Silca but for many years he ran racing products for Zipp. They also did research on tires, tire width and tire pressure. They had expensive equipment and pro riders to work with and came to largely the same conclusions as Heine. The pro riders were just as clueless about what made things feel fast or slow as other riders.

Otto

They werren’t talking about the difference between low-quality and high-quality tires though, but rather about width and pressure for high-quality tires. I think low quality tires are easily perceived in use when compared to high-quality tires, by anyone. The difference between a 67tpi commuter oriented tire and a 127tpi full racing tire (of same size), in my experience, is blatantly obvious.

As an aside, having known and ridden with pro racers, they’re rarely gear people, and rarely attuned to the subtleties in equipment, particularly at the edges of their performance domain. I think it’s because they’re hyper-focused on what they’re doing physically, or perhaps it’s because they have such ample ability to perform at high levels that the margins get blurry. I dunno, but pros are not my go-to references for equipment assessment, and it didn’t surprise me at all that they’d not be at all attuned at all to whether a 28c at 70psi was faster than a 23c at 105psi.

Which tire is faster also depends on speed where aerodynamics play a more significant role. At a minimum, appropriately matching the tire width to rim width pays huge dividends at higher speeds.

Rolling resistance and aero drag are about equal at 10 mph and at 20 mph, aero is closer to 80% and rolling resistance is 20%

There’s little-to-no point talking about “fast” if that kind of thing isn’t standardized for comparison. Tire/rim matching makes the system faster, bit it does not determine whether a tire is fast or not, i.e built for speed or built for durability… or traction, or something else, like economy of production.

Not true by my testing. Some tires are clearly faster aerodynamically on any rim. Just mentioning, no need to discuss.

What’s not true? Saying a bike can be made faster by aerodynamically optimizing the tire and rim combo sure doesn’t seem like the same thing as saying some tires roll faster than others, but if you wanna go all reductio ad absurdum, I agree no discussion is needed.

What you said is completely untrue. It is standardized, CdA is measurable quite easily.

Lastly, who made you queen of this thread to tell me not to contribute.

Some tires are faster than others due to reasons beyond what was contributed already. The shape of the tire and how it interfaces with the rim is key and not all tires are the same as you implied. This effect is at least as great as rolling resistance differentials when at speed.

Just say you don’t understand when you don’t understand, and spare us all the drama. It’s effin’ lame AF.

i find it really interesting how much of a difference people report between tires of similar size, type and pressure.

i must not have a very sensitive butt or hands; while i can certainly tell the difference, i wouldn’t say going from tubed gatorskin hardshells to tubeless GP5000 felt all that different, yet many described the hardshells as some sort of riding purgatory involving wet cement, broken glass, and nails on chalkboard! the difference in measured speed is far more noticeable than the difference in feel, but there are too many other variables to be definitive about that.

And a good tailwind.

I used to fill up my 25mm tires to about 100 psi and was skeptical of Silca calculator suggesting 88 psi as fastest. Then I calibrated my pump, and found it showed 8-10 psi higher than actual.

Silca recommended pressures are pretty good if you enter the right parameters and your pump is accurate.
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​​​That said, narrow tires and wheels are more aerodynamic all things being equal and that will eat up a small difference in rolling resistance. Aerocoach found 0.1W RR difference between a 23mm and a 25mm Corsa Speed (that is a superbly supple tire though with very low RR, which probably is the reason the difference is so small).

big strong legs and lungs.

^this^

I'd love to see a blind (figuratively speaking) test - 100 cyclists ride bikes back to back with the only difference being the brands of tires - all the same weight, size, tire pressure, and tubes. I would venture to say that guessing would be the most successful method of identification.

I've been riding for 47 years - BMX, MTB, road (for the last 15), and gravel (last 3) and my breakdown is like this...
- MTB, yeah I can feel the difference between an open, deep block tire from a small, shallow block tire
- Gravel - uhh... same style (block, center tread, etc), size and pressure - nope
- Road - within a 10 psi, 3mm width and 15 gram range - nope

Maybe a few more years of riding and I'll be able feel the difference ;-)

No.

https://podcasts.apple.com/us/podcas...=1000540414546

Look for tests that have been done with regard to rolling resistance differences between 23, 25, 28 millimeter tires. It is insignificant and it is air drag that is by far the biggest factor. Consider that at 30 mph the air drag is 4 times that at 15 mph and so requires 4x as much energy output from the rider. It is why racers use the peloton.

It is thought that a higher PSI tire may have greater rolling resistance as it is less able to move over a bump smoothly. A 700x25mm tire can use a 15% lower PSI fill to support the same weight as a 700x23mm tire and this makes for a smoother ride.

So in your opinion, professional cyclists basically don’t know anything about bicycles because they are in great shape and pedaling very hard.
Good stuff :thumb: