scottfsmith

The only conclusions they are drawing are on the 17 vs 21mm rims which is the only real goal of their study. The data is consistent on that.

There are many reasons why this 28mm data could be accurate. Tire manufacture is not uniform and there could be some differences in the tires. When you have a system with vibration as a key factor, harmonics also come into play and some things cancel and some things reinforce. So there could also be something going on there.

And, since they were not really after a tire comparison but a rim comparison they could have run the 28s on a different day with different road conditions. Which they should have reported, but their goal was only 17 vs 21 rim comparison which doing the 28s on a different day would not affect. The lack of 28 in the previous sheet makes me wonder in particular on that.

asgelle

The data as presented are consistent with their conclusions. That might not be true if accurate error bars were included.

Germany_chris

We do understand we aren't going to solve this in this thread right?

I'm from the fattie camp, if I go skinny it's always on quality tubulars, good quality tires are more important than how big or how small they are. Spend your money with Jan or FMB or whomever but the tire is not the thing that's slowing you down.

SlowJoeCrow

I recommend a bigger tire for comfort. When I replaced the cheap 700x25 tires on my bike with some700x32 Paselas it felt a little bit quicker and a lot smoother. plus the bike felt more stable since it's a cyclocross fram designed around 32-34C tires. Panaracers are moderately priced and the tan sidewalls look bit like tubulars so win all around.

RChung

Depends on how critical your needs are, and different people have different needs. Some people achieve their goals not because of one single thing but because of the accretion of several tiny improvements. Tires were a critical decision for Ronan McLaughlin's recent Everesting record, even with the blow-out. All happy record attempts are alike, each unhappy attempt is unhappy in its own way.

aclinjury

All these rolling resistance tests are so specific AND varied that their results are questionable in real-world riding applicability.
Has anyone done hard out-of-saddle accelerations on wide tires (>32 mm) at the psi they're intended to be used? They feel like mud. You're pushing 700-800w and still gradually losing positions. Do that 5-7 times in a fast group rides and you're shelled out the back.
Anyone tried to hold a fast corner with wide and soft tires? They feel like they're about to fold, no confidence whatsoever, causing rider to brake check and lose positions.
The only discipline I see all these RR tests can be of use is TT (on a consistent surface) or track. Real world riding, espeically in fast group rides, efficient accelerations, solid cornering, and bike control, will win you a lot more positions than any differences in tire RR will ever do.

Nevertheless...I'm still curious in these RR debates when the pop up every few months and will keep one eye open in case some new relevation comes up

tomato coupe

And he was on 25s?

Sy Reene

No, the 28mm and the 25mm seem viable. It's the 32mm chart that is the screwy outlier, showing the same lowest inflection point as the 25mm tire at the 95psi mark. It's pretty widely held that a wider tire's optimal inflation point should be at a lower psi than for a narrower tire. If this chart showed eg. an inflection/lowest point at around the 65-70 psi mark for the 32mm tire, then I could buy that their test methodology was at least directionally correct. And yes, that pavement photo doesn't seem to show anything I'd call new/smooth surfacing, so results shouldn't be close or comparable IMO to what's seen on a steel drum roller test.

RChung

Yup, but tubulars. 74 and 76 psi. Slightly used tires have lower RR than brand new tires, so he used them for a few runs to break them in. He did skid on a couple of the bottom turnarounds, which is probably what did them in.

tomato coupe

Would it be possible to summarize how the wheels and tires were chosen?

RChung

That decision was made pretty early and was already set, so I didn't ask why. There're a couple of hundred email messages discussing some hare-brained schemes we had. Fortunately, Ronan ignored the hare-brainiest.

tomato coupe

You can't tease us like that. You've got to tell us some of the hare-brained ideas.

Paul Barnard

Just curious. Are there any categories of road riders who need every speed advantage they can possibly get? If so, what size and style of tires are they using?

asgelle

For one, those who want to beat their brother in law.

RChung

The road was quite narrow. The bottom turnaround was determined by a spot where a tiny little side road came in at a "T." That made the road a tiny bit wider so he could make the turnaround at a wider spot. (The top turnaround was determined because it was at the peak gradient, but it was so slow he could make the turn in a narrow spot, then accelerate quickly. He hit a max speed of about 85 km/h before he had to hit the brakes, hard hard hard, for the bottom turnaround at about 12 km/h.) We had him try a couple of different ways to make that bottom turnaround while maintaining as much speed as possible. One of us (not going to say who) suggested that he do the bottom turnaround counterclockwise because of the shape of the approach. This is Ireland, so they normally drive on the left and the turnarounds are usually done clockwise. He tried it, and the timing looked promising, but he was very uncomfortable turning to the left after a lifetime of turning to the right. Maybe if he'd had another month to train turning to the left he could've done it.

This was one of the more serious less hare-brained ideas. A less serious more hare-brained idea was to build a banked ramp like on a velodrome so he could do the turnaround at high speed and slingshot back up the hill. Maybe it would've broken the bike (and him) but the video rights would've made it worth it. There were a couple of other ideas that were medium serious medium hare-brained but I'm holding onto those in case he needs to make another attempt.

HTupolev

That doesn't seem very harebrained at all. A cambered bottom would definitely increase the speed that you could take the turnaround at, which would both save time and decrease the braking effort at the bottom of the descent. And it's not like you'd need to raise it to devastatingly high g-forces to see a timing difference. The only obvious "issue" is that you'd clearly be poking the boundaries of Everesting rules.

RChung

So, Ronan asked. The Everesting rules guy said it would be disallowed.

Which makes me want to supertuck, throw a bottle to a bystander, and hit a ramp on a ride.

dmanthree

Funny, I'm no racer, but I prefer the so-called "narrow" tires to the big wide ones due to the reasons you mention: ride and handling. 28s is as wide as I'll go. As far as RR goes, well, that's kind of a fluid subject since there are so many variables, like rider and bike weight, rim width, road surface, average speed, etc. I take the web site as a legit data point, but with a big grain of salt since it only compares a stationary tire on a consistent surface with a consistent weight. Good lab data, but not real life. I've had the pressure discussion quite a few times, and I prefer higher pressures for all the reasons you stated. It just feels better to me.

nomadmax 

Here's something I never see mentioned in these skinny vs fat tire threads, the ability to "ride light". I see people on group rides all the time that hit bumps, cracks and rough stuff with their elbows locked, shoulders hunched and butt firmly in the saddle with absolutely no effort to unweight the bike.

aclinjury

Right. Like you, I don't dispute the data, but I'm questioning their degree of applicability to the real world. When putting the variability of the data and variability of road surfaces, it makes it really hard to make a difinitive case of "wider is better".

And then handling of a tire, which IMO is more important than RR. A tire with a great straightline RR may not be great at giving rider feedbacks in high-G corners.

Well, one thing is for sure, choosing a "perfect" tire to match your needs and style of riding should be much more than looking at a tire's RR produced from varied protocols.

James1964 

I recommend everyone move to Dubai and ride 23mm tires inflated to their max pressures; the roads are silky-smooth and well maintained. (Just watch out for the camel grates and sand drifts.)

dmanthree

I get the light sarcasm, but what you just described is essentially what I do. I inflate my tires to suit conditions since there is no one size fits all solution. Today's ride on mostly smooth roads had my tires (conti GP 4 Season) at 100/105. The other day I went in a different direction with quite a few coarse surface roads, so I used 85/90. Both choices worked for me.

The good news? Where I'm riding now camel grates aren't an issue, but there is the occasional sand blown across the road. No worries. If the same becomes a huge issue I'll move to a fat bike.

bigevil

well, heres a quick update
FWIW with no data other than 3 weekend and some good distance on the Rene Hersh 44s with psi from 35-45, I switched to to 32mm GT5000 TL this past weekend and must say I greatly prefer them. The 44mm supple tires were incredible comfortable, dare I say cozy. But I felt sluggish, especially in turns. On LA streets they were a welcome break from getting rocked around nonstop but the 32mm GT5000 just fly for me(right now playing around 50-60psi but might try lower). They're the perfect middle ground for my road days and climbing and I keep a second wheelset with 40mm super knobbies for my gravel days at 35psi.

there's been so much helpful data and opinion here, but I think like many eluded to it's really so much about personal preference and experience. For now I'm going to stick to these tires cause I freaking LOVE em.

njkayaker

​​​​​​Time trialers.

vane171

The way I see it, it is a trade of between speed and comfort. With 23c tires, I am fine on asphalt roads unless it happens to be one of those rough ones that have gravel protruding through the asphalt top. On the latter I even removed my phone from the bar holder because I was worried it might get damaged by the severe vibrations. I just avoid riding on such roads but if that limited my rides too much, I'd get 28 tires at lower pressure.

All this move from narrow to wider tires seems to be due to people coming to reality with their context in life. Nobody wants to admit to themselves that they are getting older, start preferring comfort over looks, not caring anymore what everybody thinks, and the test results of wider tires being just as good or even better than the narrow ones, comes as a release from the slavery to narrow tires

That's like the CGN test in YT video on road tests I just remembered watching once, comparing some relatively cheap bike against the top of the line bike and finding not much difference to warrant the $ expenditure if you are not after looks and don't need to cut seconds on your rides.