It seems intuitive that thinner tires should travel faster than wider tires, but maybe not.

What do you recommend for a road bike (700C) tire width and air pressure?

Here are a couple fairly recent threads on this topic.

Tire width; 28 vs. 30 or 32.

What's the optimal tire width for maximum speed on roads?

https://www.bikeforums.net/road-cycling/1231582-rolling-resistance.html

If you are asking because you have a road bike, the first step is do do some measuring to find the maximum size tire that can fit in your frame (chainstays, fork). You need at least 3-4 mm clearance, according to the info I got when I put larger tires on my bike.

NB: maximum inflated tire width doesn't necessarily match the published width number... i.e. a '28 mm' tire could inflate to 30 mm or 26, depending on the brand and also the rim width.

Vibration given off by narrower tires feels like speed but may not be faster. Go with the widest tire you can fit if a road/cross bike and if a fat bike you are riding not on sand and snow go with the skinniest tire your rim can handle.

Wider tires are more comfortable. Go over the bumps faster.

All other things being equal, wider tires have similar or less rolling resistance caused by flex in the casing.
All other things being equal, wider tires are a bit heavier than the same tire in a narrower width.
These considerations are generally true when looking at the same model tire in different widths. However, if comparing two tires that are not the same make and model in different widths, often wider tires are the heavier and thicker and stiffer type which roll more slowly, while it is easier to find narrower tires with thin and supple casings which roll better.

Depending on how closely your tire width matches your rim width, a wider tire may have more aerodynamic resistance at high speeds. A big mismatch in rim/tire width (so the tire mounted on the narrow rim has an 'omega' shaped cross section will generally have more aerodynamic resistance than a rim/tire combo that are close to the same width.

A wider tire will almost always be faster on rough or loose surfaces. A wider tire at a lower pressure will glide over surface imperfections, while a higher pressure narrow tire will tend to bounce you and your bike up and down, which is a loss of forward momentum. On soft surfaces a narrow tire will tend to carve a deeper groove while wider tires will be more likely to float on top, which uses less energy.

The great thing about tires is that they are a 'wear item', so you can try a new pair every season or so, or pop new ones on and keep the removed ones as spares or for riding different conditions. I like to take the perspective that riding enough to wear out a set of tires deserves a reward, and I reward myself with a new set of tires!

28mm minimum width for me. If the bike won't take that, I'd get a different bike.

I’d go with the biggest tire your frame will fit, and the most supple tire you can get in that size. On my bike that will fit them the 30mm vittoria corsa tubulars are heavenly.

The simplest rule of thumb is : Fat rider Fat tire. Skinny rider Skinny tire.

For an explanation, consult this chart:

There is not enough info here to make any specific recommendation. We need to know what frame clearance you have (older bikes often don’t have enough room for modern wider tyres). Also need to know your weight and how smooth your road surfaces are.

The general trend is clearly toward wider road tyres. 28 mm is now a very common width compared to 23 mm a decade ago. If your roads are rough then 32 mm is a good choice too. Typical pressures are now in the 60-80 psi range with these wider, higher volume tyres.

Minimum of 32 mm...I won't purchase any tires smaller than 32mm....My favorite size for road and off road is something around 45mm.

fwiw - my road bike has 25mm tires, I weight 225lbs + bike & use approx 100-110 psi rear & 90-100 psi front. by trial & error this work for me for our local roads

The big assumption here is that all other things are equal. Once you start looking carefully, most (not all) tire models start picking up sidewall stiffness as the width increases, usually between 25 and 32 mm wide. That's why tires wider than 25 or so often have higher rolling resistance than narrower tires. The exceptions are usually pricey.

Many road bikes older than five years are limited as to the size tire they'll take, often maxing out at 25. In that case, ride the widest tire that'll fit. Otherwise, you'll have to try a few and pick your own optimum combination of width, ride, price, and puncture resistance.

I don't know this to be generally untrue, but there are definitely tires available in multiple widths that do not follow your description. I am a big fan of Panaracer Pasela tires, which are not expensive (although not easy to find these days), and the larger widths are definitely made with the same construction as the smaller widths. To be fair, there just aren't that many tires made in the same model that come in widths from below 30mm to above 30mm, and lightweight construction wider tires are more rare than lightweight construction narrow tires.

ANyhoo, here is a rolling test of one particular model available in many widths. They even publish stats like sidewall and tread thickness, and the wide tires seem to be very similar, if not made the same as the narrow tires. The widest tire has the lowest RR and the narrowest tire has the highest RR.
https://www.bicyclerollingresistance...000-comparison

Pretty funny. Berton's calc page tells me I should be running about 112PSI in the rear and about 91 in the front. This absolutely flies in the face of all those "experts" who claim I should be running pressures much, much lower! I use trial and error to arrive at a comfortable and usable pressure, as always. For my tires and wheels I ended up at 95/100 front/rear. Just because I like the way it feels.

What's fun is you can still find sources on the interwebs referring to 25 mm as "wide" tires.

I think it is safe to say that a wider tire is more comfortable than a narrower tire.

As far as being faster, I think there are other variables that impact speed more than just tire width.

Personally, for a lot on non-competitive riders, I think dollars spent per mile probably has a greater influence on tire selection than getting the fastest tire available.

I should add that flats per ride might have a greater influence than the optimum rolling resistance. Fixing a flat turns the fastest tire into the slowest.

Everything is a compromise.

John

That's what I think too. There's lots more to it than just tire width and air pressure.

I had 25s on my old bike, newer bike has 28s and omg they are much comfier. Would never go back. And give me more confidence on the road!

I can notice a difference in speed based on the tread of the tire, but based on width is not noticeable at all. The speed differences are so negligible that I agree with you that except for racers, other considerations are generally going to be way more important. I like the way you sliced up the calculations.

I like the Conti GPs (4000 and 5000) because they are smooth (which I prefer) and durable.

Frankly if you have to exceed 90psi, it's probably time to consider moving up to the next wider tire. When I am rolling on 25mm tires, 90psi feels OK and 100psi feels like my dental fillings are going to come off.

Berto's chart has been obsolete for years and people still trot it out like it's definitive fact whenever this comes up.

Lots of variables involved. Wheel type, width, frame material and type, rider weight, etc. I use what works for me and my ride, a 2017 Roubaix that absorbs road shock really well.

Yeah, I really have no use for anything smaller than 32. All my rides include at least some trail miles, so that is the bare minimum. I run front and rear the same and lately at 60 psi though I’ve run lower, too. Anything narrower with higher pressures would be less comfortable and less fun.

Otto

That was my point; there is NO definitive source when it comes to tire pressure. Until everyone is the same weight, riding the same wheels, tires, bikes, and road surfaces. Until then, just use your brain and experience to choose what works for you.