T Stew

No, I did not start this thread and I am not saying the "wider tire / lower pressure people are full of CPAP". Maybe you need to re read my posts neutrally. I am agreeing with several others on here just pointing out the complexity of the situation. It is impossible for a certain tire size and a certain pressure to always be best for all roads and all riders. It's also impossible that wider and lower pressure is best without giving a specific range. There are several variables at play, more than just tire size and pressure (like aero drag, surface roughness, rolling resistance, rider weight, etc). And no, I don't have a double blind peer reviewed study to back up this basic concept. But neither did any of the tests I read on the internet. I did however state in my first post in this thread that I plan on doing a lot more testing to validate my own results, probably next year. Of course the results will only be specific to me and it won't be a blind study, so YMMV.

I don't plan on riding track tires on a mountain bike, that kind of comment is when I roll my eyes . I do plan on continuing to ride road bikes with tires that I have ranging from 23mm to 1 3/8" depending on conditions though (at various pressures, I don't just use a certain pressure because I read it on the internet or someone told me too).

DarKris

Just to throw a wrench in this thread: I went from 700x38c tires to 650bx42 tires. They are just as fast, more comfortable, and they even climb better. I'm also 365lbs and could never imagine going back to skinny road tires at 120psi for now even if they are "faster".

alathIN

Oops, mistaken identity.
I agree, it's a classic multivariate equation and you can't know the answer unless you know all the variables. I meant to be arguing with someone else.

garciawork

Way late to this one, and without a huge amount of data, but I built a gravel bike that was running 35c Schwalbe G-one tires, and I hit some PR's on the road on that bike. Not saying it was faster than my 23c tire roadie, as I have been getting in better shape, but it certainly wasn't slower.

Daniel S

Were they the same model of tire? Those that say their wider tires are just as fast do emphasize the point that you need to compare the same suppleness of the tire build. Just curious because I am going to try some 32mm next.

Maelochs

Daniel S, you are new here, so you don't remember Inpd ..... he was a much-respected poster here. I am glad you resurrected this thread. i t is a nice reminder ot a member who has passed.

I cannot add much to the tire debate. I use 23s on half my bikes and 28s on the rest, but because I am a mega-clyde I run high pressure to avoid pinch flats. I can say I am just as fast on 28s as 23s, and the comfort difference is notable.

My question for others is .... why is bigger considered to be better? Are 32s or 38s really that much more comfortable on good pavement? I suppose if I rode a lot of bad chipseal, yes, I would want more air in the tires, but I ride decent pavement most of the time. On good pavement .... how much comfort can a person gain without sacrificing due to spongy tires?

By the way, some people were saying that with bigger tubes and much bigger tires, a rider was adding 12 ounces to a pound to the wheelset. That can make a real difference.

I did an experiment with my Fuji Sportif. The stock wheels were anchors, and the tires were very cheap treaded 28s--I guess for gravel? I swapped in some Vuelta wheels and Conti Supersports, cutting maybe half a pound, and the bike went from sluggish to tolerable. I then went to some no-name Chinese CF rims, dropping another few hundred grams, and the bike became positively lively.

Sure, once the thing got rolling, the wheel weight meant nothing ... but at every acceleration, whether from a stop of just from slowing a little, the bike initially felt like it was pushing through peanut butter. Now it feels as responsive as my Chinese Cervelo R5 clone, (which runs hard 23s by the way.)

(As an aside---I put an extra 10 pounds of air in the front tire last night and could definitely feel the difference---for the first five minutes. A tiny bit more chatter .... but after five minutes I forgot about it.)

Whatever. As I understand it, the deal with wider tires being just as fast was that energy loss through hysteresis was reduced---the hard tires tend to chatter over bumps, and with each bump momentarily lose traction, while the slightly softer tires deform slightly and transmit full power. This doesn't seem to scale up indefinitely---Obviously a fatbike with 5-inch tires running 5 psi won't be just as fast, so it is legitimate to wonder where the various lines---aero, weight, pressure, width---all cross on the chart.

Further, with tubeless options, riders can choose to run lower pressures safety, so i kind of wonder why people would need 38-mm tires on good roads. Maybe some placebo effect?

As with most things cycling, we can look at what the pros do---many run 25s or 28s and you Know they aren't sacrificing speed---and you can then say, "Who cares what the pros do?" Unless you are rising just for speed (which is another valid way to ride, of course) then it becomes a question of how much you care about what aspects of riding. Also, since every one of us rides a different bike on different roads, has different fitness goals and levels, and different riding styles, it is very hard to compare directly. One person's anecdotal info might be 100 percent accurate and also 100 percent irrelevant to another rider.

I tend to agree with @Machka from post #4---once you get past ~30 mm you might be into the overkill zone unless you ride really bad pavement or go off-road. I can't see why a person would need or gain much from going wider than a soft 32-mm tire on good pavement. I can see where there would be efficiency losses from going very soft or very wide (based on experience---which is anecdote, not data.)

The Final Conclusion? It is all subjective. You have to decide based on your riding preferences, your roads, your goals .... I'd say you would need to experiment a little and then report back.

Rides4Beer

Def depends on your roads. They're pretty crappy here, plenty of guys go fast on skinny tires here, but you can hear/see them getting beat up. If I'm taking a hit on speed with my 32mm GP5000s, it's not very noticeable. What is noticeable for me is how smooth and comfortable the ride is while watching others get their fillings knocked out. Whatever works for you.

Daniel S

Bigger will be better if I won’t have to change out my tires to go from a pure road ride to a mix terrain ride. I would just get some 38mm slicks.
I suppose I am just starry eyed by the claim from Rene Herse research saying there is no loss in speed from 28mm up to 54mm if you are running tires of the same construction.
I seem to have scored some advise on two separate threads, thanks folks!

PoorInRichfield

Maybe you aren't faster with wider tires...

One thing I learned years ago is that what feels fast isn't necessarily fast. To me, rock-hard 23mm tires at 110 psi feel fast. Heck, I can feel when I run over an ant with those tires. When I changed from 23 to 25c tires years, it ago was like changing to mountain bike tires... I hated it at first as I felt like I was riding on marshmallows.

Fast forward to today, I now have a bike with 25mm wide rims and 700x32c tires. I thought I'd absolutely hate it. Instead, after over 2.5k miles on the wheels, "I'm a believer." (Note, I'm a believer in wide tires and wide rims, not just wide tires.)

On a track or on a ride with glass-smooth asphalt, skinny rock-hard tires might indeed be faster than wider tires. However, my reality is that the roads near me are constantly beat-up by the freeze-thaw cycle created by summer and winter. I'm lucky if I get to ride a section of smooth asphalt for more than a few miles. As a result, I physically feel very "beat-up" when riding hard, narrow tires for any distance. It is certainly hard to measure fatigue caused by a rigid bike and harsh roads. It's also hard to measure what happens when a tire bounces over bumps vs one that roles over them.

I'm fortunate in that my wide wheels (25mm rim width) and wide tires (700x32c) are very light and aero as I've ordered a custom set of carbon wheels. While hardly scientific, my average speeds this year while riding the same routes I always ride have been consistently faster than they've ever been... and I'm certainly not getting any younger! I've also noticed that when I'm done riding, I no longer feel "beat-up" like I used to. One of those factors has to be the tires as I'm now running around 60psi instead of the 100psi I used to run.

Sorry that your wide tire experiment didn't work for you, but given the right conditions, I still think wide rims and tires are worth a try.

bbbean 

Thanks for your in depth analysis, extensive data, and replicated study. If we didn't have this post, we'd just have to take the word of a bunch of engineers, coaches, and professionals who claim to have demonstrated benefits in controlled experiments studies, and races.

noodle soup

Don’t hold your breath waiting for him to respond.

aclinjury

as Wphamilton has pointed out in his reply, your cadence, power delivery, speed, are not the same in the 2 efforts. Althought the avg power over the 2 durations are the same, but there are lots of variances between the 2 efforts. And we know that... average power... doesn't always equal the same average speed when there is a lot of stochastic in power delivery.

Maelochs

The one thing I see a lot in this thread is that normal tires at normal pressures work well on reasonably good pavement, and wider, softer tires work better on bad pavement.

I am sure everyone else here is as shocked as I.

Next we'll be hearing that MTBs are faster on MTB trails than tri- or time-trial bikes.

We shall have to prepare ourselves for the inevitable shock.

DrIsotope

Man, this thread takes me back. I got two quotes of the same post four years apart essentially saying " power isn't power." Faith in BF renewed.

The bike from then died of a cracked chainstay a few years ago, I'm riding the replacement on 700x40s now... @ 58/65 for pavement. For fire roads? In the 40s. Like a cloud.

cb400bill

The OP passed away back in 2017.

Thread closed.