Reinventing the Wheel: The 25mm Revolution

Tuesday, 2 April 2013

Notice anything fat in photo above? It’s can’t be the riders … nor the spectators. Instead look at the front wheel where Matthew Goss is running a 25mm wide tyre.

One trend in bike technology for 2013 is the advent of wider rims and tyres and, accompanying this, the progress of clincher tyres. It’s common to see 25mm width tyres on team bikes today, something that was unthinkable a few years ago.

As background it was long thought that the narrower the tyre, the faster it was. Especially when riders faced a time trial wheels could appear with 18mm tyres. These had the advantage of being narrow and so more aerodynamic and because there was less material, lighter too. It wasn’t just for the special stages, much of the bunch would ride on 21mm tyres for the whole year.

Once or twice a year things got wider when it came to the Tour of Flanders and Paris-Roubaix. But go back to 2006 and the reliable build-up of George Hincapie’s chances. In a piece looking at his bike there’s talk of 23mm and 26mm for the day.

These days Argos-Shimano, Blanco, BMC Racing, FDJ, Omega Pharma-QuickStep, Orica-Greenedge, Radioshack-Leopard and Sky are running 25mm. Why? Well increased grip is one explanation. But there’s more to it. Here’s one reason:

We went from 21mm and 23mm to 25mm tyres in the last few seasons; new research shows that 25mm have less rolling resistance and I have the feeling they give more comfort and traction so it’s a win-win situation
– Koen de Kort, Argos Shimano speaking to RIDE Cycling Review, Issue 59, p95.

Rolling resistance is the resistance encountered for a wheel to roll over obstacles in its way. The smoother the road, the lower the resistance. Unlike aerodynamics this is a linear force that increases in line with speed. Do wider tyres have lower rolling resistance? Probably as they are able to deflect more on the road but it depends on the pressure of inflation. As the wheel rolls over the imperfect tarmac the tyre constantly deflects as it crosses the surface.

The narrower the tyre, the longer the measurement for S

The diagram comes from Schwalbe and they explain that at the same tyre pressure, a wide and a narrow tyre have the same contact area. A wide tyre is flattened over its width whereas a narrow tyre has a slimmer but longer contact area. The long flatter area is less round so it doesn’t roll so well. In other words the shorter the S-measurment, the rounder the wheel. Bikeradar has more on this.

The evolution of the revolution

But there’s a new factor as well to explain the adoption of 25mm tyres in the peloton and it’s come through rim design. I think it began with Zipp’s Firecrest models (edit: I was wrong, it was HED, see comments below) which use a wider rim that’s bulbous in profile as the cross-sections above show. The wide profile is supposed to offer improved aerodynamics but what’s certain is the width, the rim is so wide it cannot be swapped easily with a standard rim because the brakes need adjusting. This was evident with BMC Racing earlier this year when they were marking bikes with tape according to what rims they’d got. BMC use Shimano wheels, the Japanese manufacturer is also offering wide rims. The same for Bontrager and we saw Fabian Cancellara in the Tour of Flanders using broad rims from Bontrager.

Wide = Strong
I have another theory about wide rims. They may offer increased aerodynamics but they are stronger too. Being wider means a larger arch which helps brace the rim against impacts, infact the sidewalls can offer some slight flex outwards. Here the rim can, in a tiny way, act like a tyre to dampen impacts. This is good for pros pounding the cobbles… but even better for manufacturers who get fewer breakages and returns after selling wheels to weighty weekend warriors. Put another way rims might be more sold as more aero but they’re certainly stronger too.

Clinchers, a stage to tubeless?
Finally a note on the topic. For years clinchers were an inferior product and required a heavier rim because of the sidewalls with hooks. The rim weight remains but because the mass market is dominated by clinchers a lot of R&D has gone into improving them. To the point where they offer lower rolling resistance. We’re now seeing riders using clinchers in time trials because they don’t mind about the wheel weight when they’ve already got a heavy disc on the back wheel.

Looking ahead one day perhaps all riders will use tubeless tyres. These have the body of a clincher but there’s no inner tube since the bead forms an airtight seal with the rim. It’s used on some mountain bikes and of course cars but the market is limited for now with road bikes. But if the market can adopt 25mm tyres when once upon a time it would have been unthinkable, who knows?

Eddy Merckx Bike

Summary
Once reserved for training, touring or Paris-Roubaix, now 25mm tyres are being used by nearly half the World Tour peloton. Increased grip and better rolling resistance come with width. But comparisons with the past aren’t fair because modern casings are much more supple yet lighter, you can have a 25mm model today that would have felt like a tractor tyre a decade ago.

Is there a big difference? Probably not but everyone is hunting for marginal gains. The revolution is in the spin of the wheel rather than design, the difference of two millimetres is evolution. Tyre width also also a function of the rim choice, it’s not just a question of glueing on wider tyres. Teams running 25mm are often those with wheel sponsors supplying wide rims. Squads on narrower rims, for example using the Campagnolo Bora, are using 23mm. Tyre pressure, the rubber compound used, the condition of the roads, the tube used inside and more all have their say. But fat tyres are here to stay.

GWR April 2, 2013 at 8:30 pm

Interesting developments, indeed.

I’ve been running a 25mm tyre on the rear for my winter bike, and recently got a wider rim on the rear of my race bike but still with a 23mm tyre. I’ve also been running my psi a little lower front and rear (about 90 and 95) for most riding. Trouble is, I really can’t tell the difference between a few mm or psi here and there.

Jon April 2, 2013 at 8:32 pm

Good read. I’ve been trying them and can’t tell if they ride faster until I start cornering. Grip is noticeable. Just feel more confident.

Acciaio April 2, 2013 at 8:41 pm

What pressure do they run the 25’s at? In the same way that traditionally smaller was associated with faster so was high pressure, another myth perhaps…

Mark April 2, 2013 at 8:51 pm

Pressure is everything. I have friends who ‘think more is better’ but when it comes to pressure they’re wrong. There’s a sweetspot and it’s lower than most people think. I run Michelin 23s at 95-100PSI but 25s go to 90PSI for 25mm.

The Inner Ring April 2, 2013 at 9:02 pm

You need to get it right for your weight too, so a 55kg climber is different from the 80kg cobble eater.

Kyle V. April 3, 2013 at 4:36 pm

I’ve been using bikeforums user Psimet’s equations to determine pressure for a given size tire for a long time and it has worked really well for me. As a 170lbs rider on 25mm tires I run 100 on the back and 90 on the front. Below are his equation:
“Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67

Example: You are 150lbs running 28’s

Pressure (psi) = (0.33*150) +33.33 = 82.83psi (rear)
Front Pressure = .9*Rear Pressure = .9*82.83psi = 74.55psi front”

wayneh April 2, 2013 at 8:44 pm

I am a recreational rider gradually switching out my various bike/wheelset combinations to 25mm tires. If nothing else I feel a psychological edge when cornering and descending, but also greater comfort on longer rides. Thanks for providing the in-depth commentary.

plum April 2, 2013 at 8:50 pm

They felt slower to me. Science does not support my feelings. I feel so alone.

AndersB April 3, 2013 at 7:46 am

Narrower tires and higher pressure feels faster. Only it isn’t.
Same thing with cross-country MTB racer reluctant to switch from non-suspended to suspended forks, frames etc. And to wider tires, lower pressure, from 26″ to 29″ wheels etc. The faster option tends to “feel” slower.
Appearantly Michael Schumacher once said: If the car feels fast, it isn’t …..
(can’t find the exact quote, got this from a friend)

Stephen April 3, 2013 at 9:50 pm

I can stand beside you on this. I’m currently using a set of Origin-8 tires at 25mm, but had to switch over to an older pair of Panasonics in 23mm for a couple of rides, and the 23s “felt” faster because they were harder from more psi. Both sets are otherwise mid-range quality.

Strava told me than any actual difference was negligible.

Which reminds me of the one rule I keep forgetting. If it’s not broke, don’t fix it. Pick the tire that gives me to most confidence for the conditions, and stick with it.

Anonymous April 4, 2013 at 12:39 am

You could become a religion!

Mark Rushton April 2, 2013 at 8:50 pm

Article in the current issue of Cyclist on the pros/cons of wider tyres and it’s not clear-cut altho’ 24/25mm seem the optimum width. The arrival of wider rims has pushed this trend. Reynolds have 24mm clincher rims coming soon. The wider rim allows a less bulbous tyre profile and a certain lessening of pressure.

Samuel Gamester April 2, 2013 at 8:57 pm

Narrow tyres at very high pressures have lower rolling resistance on a perfectly smooth, hard surface – the ultimate expression of this is a train with steel wheels on a steel rail. However, as soon as the surface becomes imperfect (tiny bumps, grit, cracks) then a wider tyre at lower pressure will actually have better rolling resistance because it absorbs surface imperfections rather than juddering over them. The benefits of wider tyres have been put forward by among others, Grant Petersen, Jan Heine, Jobst Brandt, Sheldon Brown and Schwalbe for some years now, it seems the pro peloton is at last catching up and rejecting tradition in favour of scientifically measurable improvements. Hopefully normal cyclists can now stop torturing themselves with excessively narrow tyres and embrace comfort with 28-38mm tyres, which is what everyone used to use before marketing and fashion interfered with common sense.

Josh April 4, 2013 at 6:16 am

Not to nitpick, but I believe that bicycle sage Jobst has been a long time advocate of skinny tires and very high pressures.

Gert Stegeman April 2, 2013 at 9:10 pm

But it started with HED Cycling. They build a 23mm wide rim (C2) since 2006.
I do ride them since 2009 and I like them!

The Inner Ring April 3, 2013 at 1:22 pm

I stand corrected, thanks Gert.

sea_biscuit April 2, 2013 at 9:16 pm

A dedicated bunch of German enthusiasts looked into this a few years back. Published I believe in bicycling quarterly. Answer wider equals better but overall load important. If I could attach a pdf of results I would

The Inner Ring April 3, 2013 at 1:23 pm
JEG April 2, 2013 at 9:57 pm

I’ve been riding the HED Bastogne wheels with their wider rim profiles for 3 years now (23mm tires at 90 psi), and I will say that the improvement in comfort most of all is amazing.

Samuel touches on the issue, but I think there is an additional point to bring up. Another big change that has accompanied these wider tires is running lower pressure. Recent research has shown that there is less resistance associated with the tire deforming to accommodate surface imperfections (this is known as hysteresis) than a tire at higher at higher pressure not deforming but instead causing the bike to bounce and move about.

At these lower pressures, having a wider tire works as the Schwalbe diagram above shows.

Alex TC April 2, 2013 at 10:11 pm

I´ve been riding and singing the praises of the HED Ardennes since 2009. They make my 23mm tires look, feel and ride like 25´s without the added weight so I´m sticking to those for now (not that it makes any difference to me or my riding style of course…).

I can´t really tell about the lower rolling resistance but you just get used to the extra grip and comfort, those are very real and present in every ride. The worse the pavement, the better they get… and if it´s raining, even more so. As a plus, it´s a lightweight set and tough enough to handle everyday training and the occasional race.

It was love at first ride and I can´t go back to narrow rims or tires. I´m just glad we have more options now, also in carbon and deep section wheels that add aero gains to the above.

Larry T. April 2, 2013 at 10:26 pm

Finally, something I’ve been longing for comes true in technology – something truly of benefit to the regular bike enthusiast. For years I’ve been called the equivalent of a Luddite for claiming the average bike rider would be better served by a bike optimized for Paris-Roubaix or The Ronde than one optimized for racing up Alpe d’Huez ahead of a follow-car. But these developments should be no surprise from an industry that has already pretty much milked the aero and lightweight marketing strategies dry…..comfort, traction and better control will be the “next big thing” in the marketing maven’s playbook – with no complaints from me…as long as it’s really true rather than just marketing BS.

Stephen April 3, 2013 at 9:55 pm

The irony of your last statement is that “comfort, traction, and better control” are essentially the first thing one should have addressed when buying a bike and having a fitting done…

Touriste-Routier April 2, 2013 at 10:29 pm

I firmly believe that all things being equal (adjusting inflation pressure accordingly), that wider is faster, more secure in corners, and more comfortable. The physical limiter to wide spread adoption of 25 mm and beyond seems to be frame design- the majority of race/race inspired bikes just can’t go beyond 25 mm; quite a few of them can’t even get beyond 23 mm. Hopefully the frame/bike manufacturers will wake up to this trend, and design accordingly.

bob April 3, 2013 at 3:53 am

Faster until the drag created by the extra width becomes greater than the gains in rolling resistance, that is. As with most things in life, there is no cure-all. Optimization depends on extenuating conditions.

That Said, on most paved roads the extra surface are begins to make the Drag significantly greater once you start getting around 28m. Sweet spot for most of us non-racers is somewhere between 23-28, again depending on the quality of pavement, crosswinds, and riding speeds.

Samuel Gamester April 3, 2013 at 10:42 am

Can you link to a study that backs up the 28mm threshold?

Dylan April 3, 2013 at 7:06 pm
Anonymous April 2, 2013 at 11:04 pm

For a few years now I have been looking at the developments of the Paris Roubaix set up on pro’s bikes and can’t help thinking that this is more or less the set up needed to ride/race of the average UK road. The surfaces of which are generally becoming like the moon. So yes, more development in this area can only be a good thing.

channel_zero April 2, 2013 at 11:27 pm

The Paris Roubaix setup is more than enough in all developed countries.

FWIW, Andy Hampsten has his name on a great all-around bike design. Of course, that challenges the equipment fetish many cyclists have.

The Inner Ring April 3, 2013 at 1:25 pm

It’s a subject I’ll return to later this week.

Andrew April 9, 2013 at 6:54 am

Yeah, I’d like to see more fork / frame clearances like this: http://www.bikeradar.com/gallery/article/pro-bike-johan-vansummerens-cervlo-r3-mud-36954/7

Short reach brakes with the pads slammed to the bottom so you can fit a 30mm tyre in there.

channel_zero April 2, 2013 at 11:23 pm

I’m old enough to have been through a number of fads. Some of the worst offenders, bottom bracket brakes, non-circular chainrings, air pressure fads (!) and now rim width.

Put some 25c tires on your bike and fill them to 100PSI and you are done.

Judging by the comments, apparently some of you have bikes that cannot accept a normal width tire??? How does it make you feel to spend thousands on a bike and it doesn’t even accept a 25c tire?

Darren April 2, 2013 at 11:27 pm

I read an article early last year about a Finnish university study into rolling resistance, tyre width, where they came to the conclusion that due to wider tyres a mountain bike was a faster option than a road bike, barring aerodynamics, of course.

I know an ex-pro who does all his winter/spring road riding on his cross bike due to the better traction offered by having wider tyres! Also makes sense given the type of roads we have here in Flanders!

Since the beginning of this year I have been riding on a set of Shimano Ultegra training wheels, which, according to Shimano are designed as tubulars but can also be used as clinchers. I have been using them as clinchers and they work great! I just need to be more careful when mounting tyres so as to avoid inner-tube pinch.

Goonie April 3, 2013 at 5:14 am

Barring aerodynamics, a Range Rover has a higher top speed than a Porsche Boxster.

I’d like to see some actual numbers to show that the decreased rolling resistance from a 25mm tyre outweighs the increased drag.

Clinton April 3, 2013 at 7:09 am

There are so many factors in play here that such an experiment or equation would need to account for the specifics that are relevant to you in a specific situation. ie. what tire on what rim at what speed on what road surface at what incline at what tire pressure at what rider weight etc. of course a number of these things are variables also.
A 25mm clincher on a slightly wider Shimano C24 rim at ~90 PSI front and 95 rear feels good for my roads, weight, type of riding etc. If i weighed significantly less I could probably get the same balance with a 23mm at the same pressures, but if i use a 23 now for my near 80kg then I loose on traction and bouncing over bad surfaces because I need higher pressure for resistance to pinch flat.
The data of a test will just help you to apply an understanding the interaction of all the factors, it wont give you an answer.

ave April 3, 2013 at 12:12 am

I use 25s on my winter bike, certainly feel more comfortable. But I run significantly less pressure too, so it might be the pressure only.

Anon April 4, 2013 at 4:07 am

The point is you can’t run as low pressure on 23mms..

Litespeed April 3, 2013 at 2:56 am

Interesting that all top level velodrome riders remain using 18 & 19mm tubs pumped upto 180-220 psi.

Guess this is because the velodrome is smooth, but the question remains, that track is always the playground for aero developments & power trends, so is there no advantage in both aero/rolling resistance/power down by using wider tires?

It could all just be marketing hype so the wheel makers have less returns & more surface area to put stickers…

Velomedic April 3, 2013 at 5:50 pm

They can do this on the velodrome because the surface is so smooth that this combination of high pressure and aerodynamics become very important. The “real world” conditions change everything though. One other issue not touched on here is contact patch. You can’t go forward or corner if your rubber isn’t on the ground. With wider tires at lower pressures gives more contact so you can more easily propel yourself over these deformities and the power you put in the pedals goes to the tires. It’s a big reason us cross guys run 25-30 psi on our cross bikes. If the wheel is leaving the earth you are instantly going slower. Finding the balance between drag and force is a shifting sand scenario that really depends on what and where you are riding.

Steve Crawford April 3, 2013 at 3:17 am

I, for one, welcome the eventual introduction of the Surly Moonlander into the pro peloton.

eggy April 3, 2013 at 4:21 am

Correction, HED started using wider rim profiles for their aero wheel lineup BEFORE ZIPP did.

The Inner Ring April 3, 2013 at 1:26 pm

Yes, Gert Stegeman has mentioned it above and you’re both right.

Joe K. April 3, 2013 at 10:02 am

There are three main forces in play during the rotation of the wheel on a given surface: (1) weight around the circumference of the wheel, ie., rim, tire, tube; (2) resistance from friction as the tire makes contact with the surface (not talking about rolling resistance); and (3) resistance from friction with the air around the tire, the rim and the spokes. Given the relatively high quality of all wheelsets these days, unless you’ve just ridden a set of heavy clunkers from the 70s or 80s–gotten off, and immediately changed to a new set of Zipps–you won’t notice the interaction of these forces much, except maybe for the weight around the circumference, which has the greatest impact on the power needed to rotate the wheel. So it sounds like most of the commenters here are actually describing the “feel” of variations in tire pressure, rather than the nuances in feel resulting from a change from 23mm to 25~28mm, which is probably imperceptible. But hey, cycling is both physical and mental. When you’re going uphill full-out, heart maxed out, about to puke, you start having paranoid thoughts about those extra 2~5mms, and that extra 90 grams of “dead-weight.”

Anonymous April 4, 2013 at 5:12 am

“the weight around the circumference, which has the greatest impact on the power needed to rotate the wheel”

The weight of a wheel has no impact on the power required to maintain a given speed. Newton’s first law of motion applies.

Weight is only a factor when an object is being accelerated or is changing height (work done against gravity). Wheel weight is one of the smallest factors to consider with respect to the power required to propel a bike and rider.

All that wheel weight does (and where that weight is) is impact the strength and handling characteristics of the wheel, similarly to how the way the wheel is built also affects its strength and handling characteristics.

There are real and measurable differences in the rolling resistance and aerodynamics of top level road race tyres. Pros often do not ride the best or most suitable gear. They typically ride what they are required to by sponsors, and in that sense watching what they use can be a poor means to assess what might be the best choice for your own racing.

Anonymous April 4, 2013 at 6:08 am

Wow. That would be true if every rider was pedaling perfect circles, with absolutely constant torque to the cranks. In reality, nothing could be further from the truth. We constantly accelerate and decelerate the wheels, more dramatically so when out of the saddle on a climb. As a rule of thumb, a pound saved on the wheels is worth five pounds on the rest of the bike.

Something else to be considered: At 40 km/h, the top of a wheel is traveling relative to the air, at 80 km/h. Air resistance increases as the cube of the speed, so a 25 mm tire would definitely encounter more air resistance an a 23 mm tire, perhaps enough to negate the advantages in rolling resistance.

Goonie April 4, 2013 at 2:47 pm

Um, no.

It is true that a heavier wheel will take more energy to accelerate. However, that energy doesn’t go anywhere; the heavy wheel essentially stores that energy and gives it back as the wheel decelerates more slowly than a lighter wheel would.

The only time wheel weight matters more than weight elsewhere on the bike is when you’re accelerating and the stored energy in the wheel rotation isn’t used up; this would happen, for instance, on a tight crit circuit where you accelerate and then immediately on the brakes again; in that case all that extra stored energy ends up getting turned into heat.

Alex Simmons April 5, 2013 at 4:17 am

Not sure why I came up as anonymous before,.

Anyway, what you are saying is a common myth/misunderstanding. When you inspect the actual variations in wheel rotational velocity during a pedal stroke, you would see that the variations in power demand due to this is so small that we are talking milliwatts.

here’s an example, in metres per second, of the wheel speed variations during pedalling:
http://www.fototime.com/0B1CD74776F6C71/orig.png

If you do the maths, and even assume really large differences between wheels with different rim masses and/or moments of inertia, you’ll soon see that the energy variance due to wheel/rim speed changes is still *tiny*.

Keep in mind that the entire bike+rider system has a lot of inertia (regular inertia and a little bit of rotational inertia), such that the pseudo-sinusoidal pattern of torque application makes very little difference to the instantaneous speed of the rider during a pedal stroke (and hence very little difference to crank rotational and wheel rotational speed).

And as Goonie says, don’t forget that a wheel (or any rotating object) imbued with greater rotational inertia also requires more energy to slow down, or put it another way, once up to speed it doesn’t slow down as quickly either. Another basic physics principle called the conservation of angular momentum.

Hence a heavier wheel would tend to smooth out speed variances due to variable power supply (but in reality wheel rotational inertia is at least 2 orders of magnitude smaller than the inertia of the entire bike + rider system).

Happy to point to some helpful sources of info on the physics and what matters (and what doesn’t).

Alex Simmons April 5, 2013 at 4:23 am

BTW – here is an item on the physics of this I did for fun (the old “aero vs weight” debate):
http://alex-cycle.blogspot.com.au/2013/02/the-sum-of-parts.html

Kjetil April 3, 2013 at 10:24 am

I’ve been using 25mm “rough road” “racing”clincher tires like the Conti GP4season and Schwalbe Ultremo DD with latex tubes on 15c (15mm inner width. A Hed Belgium/Ardennes is 18c IIRC) rims (Campagnolo Zonda wheels) as all round training and gravel bomber tires for three seasons now. Normally at 6.5/6.8 Bar f/r for my 73 kg. Very nice.

For racing and those arch-Norwegian long distance double paceline TTTs I use a set of FFWD F6R high profile wheels with 22 mm Veloflex tubulars. These rims are Bora-narrow, and I’d use 25s on Zipp Firecrest or HED SES.
This 22mm tubular setup is smoother in feel than the 25mm clinchers. I haven’t tried a 25mm Veloflex clincher on the Zondas yet…

A word on bikes: Mine’s a Bianchi Infinito, a De Ronde/old geezer’s type frame. Maxes out at 25mm, so you won’t see it at Roubaix.

AK April 3, 2013 at 11:11 am

The physics of tire width/rolling resistance is very old. The only relatively new thing is that they found out that with the proper shaping, wide rims can actually be very aero, esp. if you take the yaw angles in account.
One difficult thing about tire width is that the optimum depends a lot on pressure and road conditions. The difference in rolling between a 28 and 23 tire is minimal if you ride them both at high pressure on a smooth indoor track, and there are no crosswinds so the aero and weight advantage of narrow tires may win. On a track or pristine tarmac higher pressures will always lead to lower rolling resistance but the gains level off at some point. It’s the deformation of the tire that leads to losses. But on a rough surface, you will start bouncing if the pressure is too high, which leads to loss of energy and traction. There lower pressures will help you, and not just for comfort also for speed and safety. Lower pressures on narrow tires give problems with pinch flats or rim damage.
If the ground is soft (cyclocross, MTB), it will be the ground that deforms and not the tire, which almost always leads to more losses. So there, the lower the pressure the lower the rolling resistance.
So there’s not one simple answer if you’re looking for the optimum speed.
For me (but perhaps also for a lot of pros), the comfort is a very important factor, so I ride 25mm at 6 bar. I’m really happy to see road tubeless becoming more widely available. When my current rims wear out, I’m definitely going to switch, so I can run lower pressures without the weight penalty of 28 mm or the hassles of tubulars.

keck baker April 3, 2013 at 8:27 pm

Hey, fyi I have converted a few different style clincher wheelsets to road tubeless with great success. They are my go-to crit wheels. I run about 95 pounds and the cornering is great Also use them on really ruff courses/gravel etc. One wheel set is an easton ea 90 and the other is a velomax (whatever their top of the line clincher is) .

keck baker April 3, 2013 at 8:29 pm

Velocity is the other wheel set ^

Steppings April 3, 2013 at 1:27 pm

It seems that “comfort” for a lot of people is not trendy or cool or whatever. I guess those kind of people choose to ignore the fact that being beaten up on a super lightweight mega bike will induce enough fatigue to more than cancel out any benefit.

Larry T. April 3, 2013 at 3:04 pm

+1

Gingerflash April 3, 2013 at 2:51 pm

Just a mild warning to consider whenever we’re told what the pros prefer.

Their riding is rather different from what most of us do. They have a weight limit for starters and the vast majority of their bikes would be under it as stock, so adding an aero bit here and a wider tyre there is fine. The weight penalty of these things is irrelevant (though weight distribution might be I suppose). Ballast in the seat-tube vs a marginally faster-rolling tyre? That’s pretty easy. However, a marginally faster-rolling tyre vs a few less grams, that’s not quite so obvious.

Also, they’re rolling along at 25+mph for six hours a day, maybe 35mph on the flat in the last 10-20km. how many of us do that? At the lower speeds most amateurs do, then these factors have different importance. Do aero wheels really make a big difference when you’re doing 18mph on a rolling liumpy route? I’m sure they do if you ride like Cancellara, but few of us do.

Wider tyres might still be great for lesser riders, but we can’t assume that if it’s good for the pros, it’s also the best thing for ordinary riders.

Anon April 4, 2013 at 9:09 pm

Agreed.
It is so easy to believe that as amateurs – we can hold ourselves to the same standards as professionals do. Is that a touch of hubris?

I’m not immune to imitating PROs either, so it is something to think about – the nucleus of our consumption and our sensitivity to changes in professional details.

How much gear will one go through, on the defense of marginal gains, while being a marginal bike rider? Would your life suddenly change or get better – moving up 2 places at the local so-and-so TT? Are you expecting development teams to come knocking because of these gains?

I’m not attacking people’s ambitions – I am identifying the difference between more watts and less drag. I see so much advertising regarding reduced drag, save watts, etc. The other side is working your @ss off to gain watts. No one will market honest hard work – because the only beneficiary is you.

Gingerflash April 10, 2013 at 2:53 pm

I think the greatest performance enhancing items for most amateurs are things that make riding/training more enjoyable and easier to fit into daily life. Turbo trainers and Sufferfest videos; Garmin devices for watching the data; better bad weather clothing; anything that encourages or assists more time on the bike.

Cody April 3, 2013 at 4:45 pm

I run Velocity A23 Rims which are a wide profile with 23mm Bontrager Tires. I’ve been seriously considering switching to 25mm tires for the lower spring rates it offers. I exclusively train on my road bike so any small amount of added aero drag I don’t care about.

And yes switching between wheels can be a bit of a pain.

Edward April 3, 2013 at 4:45 pm

From the article: “The diagram comes from Schwalbe and they explain that at the same tyre pressure, a wide and a narrow tyre have the same contact area.”

This is an invalid comparison: if you’re comparing tyres of different widths at the same pressure, at least one of the tyres is at the wrong pressure. You can’t compare tyres of different widths at the same pressure.

Bernat Cyclo April 3, 2013 at 5:23 pm

I can only agree with the 25mm tires and wider rims.
Now riding one bike with wider Alpha Stan’s rims, and 23s feels like 25s. Next tires will be 25s to check…

Hobbanero April 5, 2013 at 8:27 am

I have found that my 23mm Conti tires measure out to 25mm when mounted on wider rims (eg. my HED Ardennes or Zipp Firecrest). So, your 23s feel like 25s because, in fact, they are.

Tom h April 3, 2013 at 6:46 pm

I don’t think this has been explicitly stated above , or maybe I missed it, but the assertion “wider tire = lower rolling resistance” is strictly true only when both the narrow and wide tires are at the
**same inflation pressure**

How many people do that ?!

Most riders on 25mm are likely to reduce the pressure by ~10 psi, compared to 23mm … which may negate any slight reduction in rolling resistance.

I’m unaware of any studies or measurements of cornering performance vs tire width, but that may be another potential benefit of wider tires.

CD April 3, 2013 at 6:49 pm

What race and what climb is the photo of Goss from. Who from Garmin is walking?

Not much discussion about road tubeless. Seem much more popular in the US than in Europe. I love them and run them abut 85psi and 90psi.

Kjetil April 3, 2013 at 9:49 pm

It’s the infamous stage six of Tirreno-Adriatico this year.
Can’t say who the Garmin-Sharp rider is, but the Katusha rider is walking too, like many others were.

steve April 4, 2013 at 1:57 am
Abdu April 4, 2013 at 4:07 am

How come you picked Matt Goss for an article which talks aboutn “being fat”…?

Just askin

The Inner Ring April 4, 2013 at 8:56 am

Because the front wheel is close to the lens, there were some from the cobbled classics but this would confuse the story because it is not about the special tech for the cobbles but everyday use.

Josh April 4, 2013 at 6:09 am

Am I the first person to point out that Zipp is not Japanese? They’re entirely American. Owned by SRAM, an American company, and all their wheels are made in Indianapolis Indiana. They’re so American that their old factory was across the street from the Indianapolis Motor Speedway, home of the Indy 500. They’re more American than Toby Keith, but only slightly less than NASCAR.

Josh April 4, 2013 at 6:11 am

On second that, is “BMC use Shimano wheels and as well as Zipp the Japanese manufacturer is also offering wide rims” just a really clumsy sentence? I think so. My mistake.

The Inner Ring April 4, 2013 at 8:57 am

You’re right. I’m always pressed for time and of course there’s no editor here. I’ll rework the sentence.

As you say Zipp are from the US and owned by SRAM, as I’ve listed before http://inrng.com/who-makes-what/

Ken April 4, 2013 at 2:48 pm

I’m strictly a recreational/exercise rider. I once thought of buying a high-tech, lightweight (e.g. expensive) bike. Then, I figured losing a couple of pounds off my own frame would be better for me and cheaper! It still comes down to turning over the pedals. I have a feeling Sparticus could win some of the classics riding a Huffy with training wheels.

Chuck April 7, 2013 at 9:03 pm

I was also expecting more coverage of tubeless clinchers in the article. When they came out a few years ago I really thought they would take over the non-tubular market and we would see the end of inner tubes for serious road wheels but this hasn’t happened. The advantages seem fantastic (though I haven’t tried them personally), lower pressure, less spinning weight (sans 60g for the tube), fewer flats…what’s not to like? What happened to the revolution?

The Inner Ring April 7, 2013 at 9:11 pm

Superior products don’t always reach the market. See Betamax video cassettes for example.

But if a team could be sponsored to use them and demonstrate the benefits this would change. Some have tried them, like FDJ but it’s been on and off.

Gingerflash April 10, 2013 at 2:58 pm

Tubeless on mountain bikes is great. however, one issuing is known as burping, where, on big hits, a bit of air escapes between tyre and rim. On a mountain bike, at say 24psi, you might lose 1-2psi, not a big deal. On a narrow high pressure road tyre, you could neasily lose 10-20psi in a fraction of a second.
Also, getting a good seal is pretty tricky. Mountain bike tyres tend to lose a few psi over the course of a week, air going straight through the sidewalls. At road bike pressure this is a much bigger problem. To prevent this, the tyres have to be made with much thicker carcasses, which are less flexible, which incdreases weight and increases rolling resitance.

Greg Sampson April 9, 2013 at 5:16 am

Interesting reading in both the article and the comments. At present I ride a CX bike exclusively after recently relocating and thinning my cycling collection from four to one. I bring this up only because I previously rode/raced track (21c), commuted fixed (25c) and trained on a road bike (23 sew-ups) as well as the CX (35c). Every bike I owned had a different variation of wheels and tires, but that was due more to my own desire to try different things. Based on all the miles on various combinations of width and tire style (clincher or tubie) I would be hard pressed to say that any of them were superior or inferior.

One obvious difference is that changing from a 35mm CX tire to a 23mm slick on the road (same bicycle) does result in an immediate and obvious change to the effort required to maintain the same speed. Of course the CX tires have knobbie tread, and I imagine that has a greater impact than width. As for super narrow track tires at high pressure… it is tough to say. I raced on very pedestrian box section rims (DT1.1) and borrowed a rear disc once (ZIPP) for a few races. The disc did necessitate a gear change and I picked up a tooth on the chain ring for the same events, as a result of the disc. Whether this was due to stiffness or aero I am not nearly smart enough to know. But when you race on the same gear all the time because you know your cadence and how your body will react, picking up a tooth was a big deal.

I have not seen any mention of wheel stiffness in the comments, but perhaps I skimmed and missed it? With the suspension of a bicycle being a direct component of the wheel/tire I wonder if the advent of stiffer wheels (carbon, high tension) has necessitated a movement toward a tire with more deflection. A wider tire may also have a higher sidewall, therefore providing additional suspension for the entire system. An example of this would be the very high sidewall of a Formula 1 tire in comparison to a touring car. The F1 tire is designed to act as an integral part of the suspension geometry, and as such the travel is only a few CM. Contrast this to a touring car that has more travel in the suspension as well as a chassis that is far less rigid. As a result the sidewall can be far shorter because it is not being depended upon for deflection as a means of suspension.

Another thought on tire width… in a past life I road raced motorcycles and there was a very obvious difference in handling and set-up from one brand of tire to the next based upon the tire profile. A race tire has a very peaked surface that minimizes the contact patch when held vertically (straight up) and maximizes the contact patch when the motorcycle is leaned over in a corner. This peak made the bike want to lean over, and traction (as well as confidence) increased when tipped into a corner. I have noticed this profile, although less dramatic, on bicycle tires. It makes me wonder if some folks are experiencing cornering confidence or suppleness as a result of the profile, and not the 2mm of additional width?

Kjetil April 9, 2013 at 9:37 am

Your last paragraphe is food for thought.
The wide clincher rims that have surfaced lately (Hed C2, Zipp 101 and FC clinchers etc), typically 18c, all make a given tire wider, but at the same time shallower than they would be on a more traditional 15c rim.
Makes me think that these rims are better paired with a 25mm tire than a 23mm.

Andrew April 11, 2013 at 3:15 am

Something that I’ve not seen anyone ask about is whether the tyre manufacturers have any recommendations about the max width of the rim for each tyres. Wider rims expose the shoulders of the tyres a little bit more than narrow rims – enough to worry about for wear, for punctures or for flexing in a way not tested in their design process?

Barteos May 9, 2013 at 10:41 am

Oh dear…

The poor people who honestly believe that tyres wider than 25mm or 28mm don’t offer performance benefits for vast majority of amateur riders are a living proof of how effective marketing brainwash can be.
Marketers and magazines have been putting meaningless 23,25 and 28 numbers into consumers’ heads for so long that they’ve managed to create some sort of Matrix world in which the roadie community seems to be trapped mentally and physically.
Long exposure to the same industry standards combined with marketing/forums BS and mindless following of the pros can result in a tunnel vision…

Such narrow tyres ARE NOT “the best compromise” as many many people claim , at least not for the vast majority of non-competing cyclists cruising at 15-18mph on hoods on some broken roads e.g. UK. You DO realise that this is exactly how overwhelming majority of road cyclists use their bikes, right?

Now folks, I suggest you get some Grand Bois 700x32mm tyres, run them at the correct pressure (about 50PSI less than your 23mm) and then tell mi how “slow” they were.. ;-)

Oh.. wait! Your bike won’t have enough clearance… Lol!

Mat June 13, 2013 at 5:36 am

do you need 255mm tubes with a 25mm tyre? or would 23mm tubes in a 25mm tyre be ok?

Anonymous November 3, 2013 at 4:01 pm

I run 21-25 tubes in my 28 tires. Not a problem at all. The weight difference between 21-25 tubes and 28-32 tubes was 60 grams per tube. Smaller tube is also easier to pack as a spare.

REVENGE June 17, 2013 at 3:54 pm

yep, I believe u kinda need 25mm inner tube (mine is 25/28) :P just got 25mm tires today!! tactile, feels so much better than 23 ♥ I believe in them, can’t wait for my 1st ride!!

Lycrathug March 8, 2014 at 12:49 pm

What a fantastic article and thread, love the fact that members of the cycling community can disagree about things without the need to doubt one’s parentage and all that nonsense.

So… I’m a proponent of narrow skinny tyres, currently running 23mm Vittoria Rubino Pros (fantastic tyre by the way, essentially a GT4000 rip off at half the price) at 135psi, my own weight fluctuates at around 175lbs and I ride an Allez. Whereas I agree what everyone says about vibration causing inefficiencies as the bike loses contact with the road, I only find this an issue on very rough roads, or when I am on a tow path or gravel trail. What I find is that on lower pressures and/or wider tyres more of these inefficiencies occur due to the bike unnecessarily soaking up the road vibration, the stiffer more rigid feel of harder skinnier tyres don’t seem to do all this unnecessary bobbing about. If I lived in a country like Germany with decent roads, I would probably go even more hardcore, 18mm at about 150lbs at a guess. Top tip I learned from the devil (Lance Armstrong) is that when you are on rubbish roads, try to ride on the painted lines as they are much smoother.

My analogy would be with my hardtail XC bike. I absolutely insist on having lockable suspension, otherwise you get unnecessary suspension bobbing on climbs that saps energy, however, when the going gets really tough/technical I switch it on to maintain better contact with the track. Similarly, my friends on full sussers, with 2.5” tyres at about 15psi will hammer me on the downhills, but when we get on to the road climbs, Lycrathug has the last laugh.

No question that wider tyres at lower pressures provide a more comfortable and safer ride with increased pinch puncture protection, but I don’t ride road bikes for safety and comfort, I ride them to go as far as possible as fast as possible.

@Velomedic, do crossers really ride at 25? That seems well low, I tend to put my XC at about 30-35. Not that I’m doubting you, never been crossing although it looks well fun!

In conclusion, it does depend on what you want from your bike, and the most important thing to go faster is to follow Eddie Merckx’s advice “Don’t buy upgrades, ride up grades”.

PS A question, being as that I have established that I like the stiff rattly ride, I’m going touring on the road bike next weekend, all the camping gear and that (prob about 20kg) will be over the rear wheel. Should I consider doing something crazy like running the rear at 145psi and the front at 120psi?

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Reinventing the Wheel: The 25mm Revolution

Tuesday, 2 April 2013

Notice anything fat in photo above? It’s can’t be the riders … nor the spectators. Instead look at the front wheel where Matthew Goss is running a 25mm wide tyre.

One trend in bike technology for 2013 is the advent of wider rims and tyres and, accompanying this, the progress of clincher tyres. It’s common to see 25mm width tyres on team bikes today, something that was unthinkable a few years ago.

As background it was long thought that the narrower the tyre, the faster it was. Especially when riders faced a time trial wheels could appear with 18mm tyres. These had the advantage of being narrow and so more aerodynamic and because there was less material, lighter too. It wasn’t just for the special stages, much of the bunch would ride on 21mm tyres for the whole year.

Once or twice a year things got wider when it came to the Tour of Flanders and Paris-Roubaix. But go back to 2006 and the reliable build-up of George Hincapie’s chances. In a piece looking at his bike there’s talk of 23mm and 26mm for the day.

These days Argos-Shimano, Blanco, BMC Racing, FDJ, Omega Pharma-QuickStep, Orica-Greenedge, Radioshack-Leopard and Sky are running 25mm. Why? Well increased grip is one explanation. But there’s more to it. Here’s one reason:

We went from 21mm and 23mm to 25mm tyres in the last few seasons; new research shows that 25mm have less rolling resistance and I have the feeling they give more comfort and traction so it’s a win-win situation
– Koen de Kort, Argos Shimano speaking to RIDE Cycling Review, Issue 59, p95.

Rolling resistance is the resistance encountered for a wheel to roll over obstacles in its way. The smoother the road, the lower the resistance. Unlike aerodynamics this is a linear force that increases in line with speed. Do wider tyres have lower rolling resistance? Probably as they are able to deflect more on the road but it depends on the pressure of inflation. As the wheel rolls over the imperfect tarmac the tyre constantly deflects as it crosses the surface.

The diagram comes from Schwalbe and they explain that at the same tyre pressure, a wide and a narrow tyre have the same contact area. A wide tyre is flattened over its width whereas a narrow tyre has a slimmer but longer contact area. The long flatter area is less round so it doesn’t roll so well. In other words the shorter the S-measurment, the rounder the wheel. Bikeradar has more on this.

But there’s a new factor as well to explain the adoption of 25mm tyres in the peloton and it’s come through rim design. I think it began with Zipp’s Firecrest models (edit: I was wrong, it was HED, see comments below) which use a wider rim that’s bulbous in profile as the cross-sections above show. The wide profile is supposed to offer improved aerodynamics but what’s certain is the width, the rim is so wide it cannot be swapped easily with a standard rim because the brakes need adjusting. This was evident with BMC Racing earlier this year when they were marking bikes with tape according to what rims they’d got. BMC use Shimano wheels, the Japanese manufacturer is also offering wide rims. The same for Bontrager and we saw Fabian Cancellara in the Tour of Flanders using broad rims from Bontrager.

Wide = Strong
I have another theory about wide rims. They may offer increased aerodynamics but they are stronger too. Being wider means a larger arch which helps brace the rim against impacts, infact the sidewalls can offer some slight flex outwards. Here the rim can, in a tiny way, act like a tyre to dampen impacts. This is good for pros pounding the cobbles… but even better for manufacturers who get fewer breakages and returns after selling wheels to weighty weekend warriors. Put another way rims might be more sold as more aero but they’re certainly stronger too.

Clinchers, a stage to tubeless?
Finally a note on the topic. For years clinchers were an inferior product and required a heavier rim because of the sidewalls with hooks. The rim weight remains but because the mass market is dominated by clinchers a lot of R&D has gone into improving them. To the point where they offer lower rolling resistance. We’re now seeing riders using clinchers in time trials because they don’t mind about the wheel weight when they’ve already got a heavy disc on the back wheel.

Looking ahead one day perhaps all riders will use tubeless tyres. These have the body of a clincher but there’s no inner tube since the bead forms an airtight seal with the rim. It’s used on some mountain bikes and of course cars but the market is limited for now with road bikes. But if the market can adopt 25mm tyres when once upon a time it would have been unthinkable, who knows?

Summary
Once reserved for training, touring or Paris-Roubaix, now 25mm tyres are being used by nearly half the World Tour peloton. Increased grip and better rolling resistance come with width. But comparisons with the past aren’t fair because modern casings are much more supple yet lighter, you can have a 25mm model today that would have felt like a tractor tyre a decade ago.

Is there a big difference? Probably not but everyone is hunting for marginal gains. The revolution is in the spin of the wheel rather than design, the difference of two millimetres is evolution. Tyre width also also a function of the rim choice, it’s not just a question of glueing on wider tyres. Teams running 25mm are often those with wheel sponsors supplying wide rims. Squads on narrower rims, for example using the Campagnolo Bora, are using 23mm. Tyre pressure, the rubber compound used, the condition of the roads, the tube used inside and more all have their say. But fat tyres are here to stay.

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