I think this is a much more complicated question than most people think. I think the greatest difference has to do with the surface you are riding on and how fast you ride.

IF EVERYTHING ELSE IS EQUAL at low speeds a wider tire will have less rolling resistance because, at equal air pressure, it has to deform less. On a bumpy road a larger, lower pressure tire will be faster than a narrow, hard one because it bounces upward less. The energy expended to lift you up with each bounce, isn't moving you down the road.

As your speed increases, aero drag becomes progressively more significant. That favors narrow tires for folks who average greater than 15 MPH and wider tires for people who average less. As you progress beyond 15 MPH the benefit of narrower tires increases.

Wheel sucking behind a Big Guy on a motor bike, will make you faster as they will push the air resistance aside..

AKA Motorpacing ... it's a thing in the training tradition..

26.5mm

Sewups.. Hand Made..

smooth tread or not??

Most strong rec riders are still way too heavy to be riding a 23mm tire. Not too heavy versus the general public, but relative to cycling.

A 44 is freaking massive. Were you guys riding through a third world country, or Detroit? I only use 32's for gravel grinding, including a patch of single track to get there and back.

dunno I'm still chewing away with these things for now ...

The optimal tire width is 26.27839mm.

Next question.

I've always ridden 700x23 or 25. My Hutchinson tubeless tires are starting to show their age so I ordered a new pair of fusion 5 tubeless 700x28 today to see how they behave.
They are likely to spin up a bit slower than 700x23 but that's not a huge concern.

You are riding boat anchors. As stiff heavy and slow as a pneumatic tire could get. Only solid tires could be worse. The rims are adequate but not much. Any tire, any tire at all, any width, that has one particle of 'performance' built into it is going to ride smoother and better and faster than what you have been enduring. Get good tires and don't worry about the fine points.

Just a few thoughts on this. Firstly, the surface you're riding on will determine the optimum tyre type. A long time ago, when roads were maintained and not continually cut up by the volume of traffic they carry now, we had wonderful smooth tarmac. In the 1980s I had 19mm tyres for time trialling, with 120psi in them. On today's roads a tyre set up like that would be almost unrideable.

Secondly, the bike construction has a part to play. I ride 23mm tyres on steel framed bikes, but find that I need 25mm tyres on aluminium framed bikes to get the same balance of comfort and speed.

Third factor is the construction of the tyre - a good quality 28mm tyre is likely to be lighter, roll faster, and be more comfortable to ride than a cheap 23mm. (The exception to this is a Gatorskin tyre which is neither cheap nor nice to ride on).

​​​​​​If you've not read Laurent Fignon's autobiography incidentally itsi well worth reading - there's a passage in it detailing how wider tyres were initially not wanted by the pro's on his team until they were tried and proved to be faster.

With the increase in tire sizes from 23 to 28, the newer rim sizes are also changing to accommodate it all. Pro riders like the one's in the Classics are asked by the bike manufacturers the two things: speed and comfort. So it does matter and eventually filters down to the mass market.

The older Shimano brake calipers like the 6600 & 6700 may not open up wide enough to accommodate the newer rim widths.

Like most here, I have a mix of 23's to 47's on my bikes.
My race bike has 25 rear, 23 front. On only one ride did I feel the need to lower the psi. 114 miles & 7000 feet elevation on chip seal has a way of taxing the backside.
The 47 bike is noticably slower in all aspects & benefits from being at maximum pressure for road. This is an extreme case with a hard smooth center ridge in an otherwise agressive knobby tread pattern. The high pressure keeps the knobs from dragging down the whole.
The bike with 41's & less agressive knobbies is noticably slower at maximum pressure (80) than with a more sensible pressure (45-50) for on road use. I think it comes down to "bounce" being transferred to "bum" & not back to road. It really shines at ~40 for gravel.

Like others have said, it comes down to the surface you are riding on, your weight, the pressure in the tire & a host of other factors like aerodynamics, tread pattern, casing construction, etc...There is an optimal for every situation. Be dynamic. On rough surfaces like chip seal it's ok to run a slightly wider than average tire bit lower. How much depends on the local riding conditions. Much cycling dogma came from velodrome type surfaces or absolutly perfect street found only in laboratory conditions where skinny & high pressure often make sense, but doesn't translate well to the real world.

As for me, I weigh185-200 pounds, on my race bike, I run about 110 on a 25 rear, & 100 on the 23 front. Some would scoff at that, but if I know where I'll be riding I'll adjust down accordingly, but never less than the 95psi minimum recommendation on the sidewall.

Not that I'm any more or less qualified than anyone else here, but I hope that helps.
Aaron

42

Large enough to keep the rim off the ground is optimal. I know that sounds snarky and unhelpful but I've been round and round with this question, and eventually I come to: the tire width within reason does matter all that much for speed.

My larger tires have typically been designed more for durability, or flat protection, or even grip, and are hence heavier and slower than my narrower tires which are typically more performance-orientated. So it's tempting to say that narrower tires are faster, but the fact is the tires are faster period. Less to do with width.

I don't want a big block in the wind or the feeling that I have to push it to spin up. But seriously, we're only looking at 6 or 7 square inches more, and given all of the things on my bike or body that take up an extra 6 or 7 square inches it's hard to take the aerodynamic penalty very seriously. So given a particular brand or style of tire, and the particular surfaces I roll on, at enough pressure that it's in that smooth rolling range, it just needs to be big enough to keep the rim from bouncing and that's it. Anything from 23 to 32 is optimal for me, if it's the right tire.

What's the best flavor of ice cream?

Rolling resistance is only part of the equation. As far as physical quality of the tire, weight, tread compound, suppleness, and aerodynamics also need to be considered. You still don't have the full story as there are rider factors that come into play. When I started out 23mm on narrow rims was all the rage, even for Clydesdales who had to pump them up rock hard to prevent snakebite. I hated the ride and the feel but put up with them because they were "faster". Then I tried Bontrager AW3 lites in 25mm and found that my speed actually increased on medium to long rides through the hills of MN lakes country. Part of it might have been rolling resistance, aerodynamics, etc, but IMHO the more important factor is that the tires were more supple and didn't have to be inflated to rock hard. The net result was that I felt more comfortable for longer and was more confident on corners and less than perfect road surfaces, so I rode faster and had less fatigue. Now I ride 25mm on a moderately wide rim on my road bike and 28mm in the same tire on a slightly wider rim on my mutt. Way more fun, very comfortable and hasn't hurt my overall speed at all. I might lose a minutia of speed on climbs but make up for it on descents and corners, and (added bonus) at the end of the day my hands aren't numb from road buzz.

i have been thinking of going 28mm on my road bike front tire and leaving the rear tire at 25mm. reason for that would be extra handlebar comfort and steering traction up front. the back wheel comfort for now is handled by the padding in the bikes padded seat.

anyone try this? does a wider tire up front make more sense?

I've often done that, mainly when I have 1 of each and I think the greater width and lower pressure gives better grip on looser stuff which I prefer on the front as opposed to the rear. But what really is the advantage as opposed to 28 on both front and rear, if you like the 28?

probably no advantage. just thinking about trying 28mm to see if the vibration is cut off the front end some, the rear is not the problem. if 28mm works in front, then the rear will wear out in time and need changing. good time to change to 28mm.

this would also be a good time to try different brands on the front without changing tires on the whole bike which may be disappointing.

at the moment i have quite a few 25mm tires on the shelf so really don't need tires, been hoping to tame my road bike vibrations some. 28mm may just do it. no doubt many here have a few skinny tires on the shelf, so how to make the best of it perhaps is to experiment with the steering a bit.

What's the question?

Yes. This has been done and is done. On most road bikes handling is improved. Whenever pointed downhill, or when braking hard, or even when cornering, weight is transferred to front. Having more rubber on road in front equals a better steering bike. Whenever a bike has two different size tires the big one goes in front.

Of course you get all these benefits and saddle comfort too if you put a matching big one in back.