28mm-32mm but I haven't tried anything larger.

It was quite the revelation the first time I put on a set of 32mm and went out on my beat-up local roads, made the whole ride a more pleasant experience, no longer had to be hyper vigilante for road hazards. If I head out the other way, which has mostly decent undamaged pavement, the 28mm's do nicely. I don't have a bike with clearance for anything larger than 32mm, but I am curious.

23 road, 40 - 50 gravel.

23 to 25 , anything bigger doesn't fit my frames or even my wheels. For hybrid gravel 32 to 37

28 on my carbon road, 32 on my gravel road tires, both are tubeless so I can run them softer for comfort. If using tubes I would go up from 28 to 32. I have a new titanium Seven frame enroute, I'll be curious as to what size tire I can fit. I have a set of OEM Bontrager tires in 28 I hope to use with tubes as the rims I have are not tubeless.

28mm for road, I like to keep the wheels light, a 30mm GP 5000 is 45 grams more than a 28, for 2 tires that is almost a 1/4 pound extra in the wheels, in the very worst location, at the periphery. I do feel that extra weight in a full blast sprint, so 28 it is, for now.

same here depends on the max the bike will take ..

Clinchers
I have settled on Rene Herse for clinchers in general 28 on the kirk with fenders 32 without but have put 35 on (not enough clearance to be comfortable but super ride, i can make a good deal (beer or coffee on these to some one local)

don't have clinchers on my Miyata or de rosa...need to build a set of wheels, but 28 max

Tubies
30 mm FMB on the Kirk
27 mm FMB on the de rosa
28 mm Corsa Control on the Miyata

My experience is wider rides ride better and are no slower (not that I am fast) I am careful to match tires and rims and i use tubes

To me it's like asking which is my favorite child. There's more to it than width. Tread, casing, etc etc. I stopped using tubulars late last century and always thought something subtle was missing. But I found that supple sidewalls made a big difference, I rode 23mm Michelin Pros for a long time on my Mercian on the advice of a former racer friend. Loved the feel. When I built my International I got Compass 36 (or is it 35?) lightweight casings and was super impressed by the quality of the ride. I didn't perceive any lack of handling or speed, unless I had them under inflated. Recently I fit 30mm Challenge Strada Pros on my Mercian and also find no loss of control or speed. At the far end, my Rivendell runs 42mm Gravelking slicks and is the fastest and most confident descending bike I own, and I've revisited tubulars with 30mm Vittoria Graphenes on my Paramount and PX10 and find them so be very similar in feel and roll to my other quality tires. Kinda like saddles, run what you like and enjoy the ride. YMMV.

I guess I'm not too surprised that someone would still ride 23 or 25 mm tires; after all some people willingly ride on Cambio Corsa derailer bikes, or penny-farthings. So, for historical correctness I guess, sure.

But now that the data is undeniable, fat/supple tires are actually faster not slower, even the pros are racing on 30 or 32, who would ride tires narrower than the pros for any reason other than historical re-enactment of the '80s?

My #1 road racer (a late-'80s Davidson) maxes out at 30 mm, and that's not good enough anymore, so I'm in the process of converting it to 650b. I think it can fit 40+ but I'll settle for 38. My sport-touring/rain bike maxes out at 32 because of fenders, so I'll probably get rid of that and build something more suitable for this old clydesdale.

For gravel, 55 mm. "Full suspension" without the weight or maintenance hassles, low psi without the pinchflats, win-win.

Even my petite ex-racer wife doesn't like 28s anymore since she started riding her garvel bike on pavement. Her Litespeed Ti road racer sits unused, and she had me make new light wheels for the gravel bike to take 40+ mm Rene Herse extra-light tires for pavement. The existing wheels will keep the Furious Fred light knobbies for gravel. The Litespeed will be sold off, basically useless since even 650b conversion wouldn't allow a sensible tire size. We won't get much for it, because nobody wants bikes with such skinny tires anymore!

Some people misunderstood the question. It was not what tires do you use because you’re limited by the bicycle used. It was “Favourite tire width”. My current favourite width is 42mm supple high performance tubeless. However on my endurance bike I am limited to 32mm.

We’re not suppose to have a favorite child?

Who? Me. I ride 25mm road tires. They're readily available from a number of manufacturers. 28s might fit in some of my old frames, but, for now, I choose 25s. I don't race professionally, so road feel is more important to me than "data."

You're not supposed to tell!

Ha, I guess "road feel" is exactly what I'm trying to avoid!

On a vintage racer, I’m a 25mm roadie. That said, took the Ironman out last weekend sporting 23mm meats. Felt just fine IMO. Fattest road bike I have rides on 32mm. It’s like driving a ‘95 Roadmaster.

Are they? I thought the point was that fat/supple tires weren't slower. Perhaps I missed one of those psuedo-scientific studies.

25's here, mainly due to historical re-enactment as a subset of what fits in my frames. I've got 28's on my commuter...can't really detect any difference.

I've got some NOS Veloflex in the 22c sizeway, can't wait to put those bad boys on.

Pros ride carbon frames with disk brakes, electronic shifting, and wide tires. I don’t. If I was told to buy a brand new bike on their dime, I would get a 2026 Grand Tour bike and love everything about it — maybe even the tubeless thing. Fat soft tires are nice on the way to the beach with a fishing rod in one hand or on a trip to a nearby store. But most of my bikes are more fun with lightweight skinny tires pumped up hard. I need to put some 23mm GP 4-5000 on my Le Champion because the 30mm Strada Bianca’s make it ride like a turd.

I can only speak for myself, but the short version is that I tried 32s and liked 'em.

The longer version is that I rode nothing but 25s for a number of years (usually pumped up to 120psi) and resisted the chorus of Jan Henne acolytes and related folks. Finally, for giggles, I decided to throw a set of 32s on my main rider to see what, if anything, there was to the growing hype. What I found was that I liked the ride. (I started with 100psi in the 32s, I now run them at 90-95 - the 25s now get 105psi or so.) I didn't notice much of a difference when I first tried the 32s. But after a few rides on the 32s, I did notice the difference going back to 25s and I liked the 32s better. Riding on 25s isn't the end of the world. I still ride and enjoy the bikes that still have 25s. On most of the roads I ride the difference is small but noticeable, more so on buzzier roads.

And as I mentioned in my earlier post, the tires in all instances are Conti 4000s or 5000s, so it's a close to an apples-to-apples comparison as I can do.

Regardless of how I might parse the OP's question, my answer is "the biggest tire that fits." The narrowest tire in my fleet is 32mm, because that's the biggest tire that fits on that bike. That one never sees gravel, and without fenders, it avoids wet roads as well.

My most comfortable bike, one that I've done maybe a dozen tours on is 650b x 42 with fenders. Since this thread is short on pics, here's "Big Red"

https://cimg9.ibsrv.net/gimg/bikefor...b929433575.jpg
1973 Raleigh Competition, mods by Peter Weigle, paint by Ed Litton.

It has nothing to do with promotion or "hype". I use big tires (650x42b Panaracer/Pacenti Pari-Motos) because I've tried 'em and I like 'em. They're much more comfortable and sure-footed than narrow tires for someone my size (200+ lb at the moment). And most of the cycling-friendly roads around here are in sad shape: not just potholes, the land on which they sit is losing the battle with gravity and gradually falling into the water(ocean or river). Yeah, the 42's are probably almost measurably slower than 25's. So what? I have no trouble keeping up with the people I ride with.

And lest you think I'm an ill-informed newb, I'm almost 72 years old, have been riding non-stop since I was 8, raced USCF for roughly 15 years, Rando'ed for somewhere between 5 and 10 years, earned two Super Randonneur medals and rode the 2008 Rocky Mountain 1200k in (just) under 80 hours. In that time I've learned a few things.

SP
Newport OR
where the weather's been worryingly nice of late.

Oh, darn.Completely forgot about 650b tires.
Likewise, prefer them 42’s, which measure up at 38+/- when mounted on A23’s.
They get you where you’re going, no matter the road surface:
https://cimg8.ibsrv.net/gimg/bikefor...2c904eb72.jpeg

These forums never disappoint! I am sure the same high pressure skinny tire brigade would prefer to drive across the country in a 65 VW Beetle because comfort, air conditioning, cruise control and reliability are taking away from the true driving experience.

Almost - I regularly drive across the country in my base model 1987 Toyota (model = "pickup"). And the thought that it is more enjoyable than driving a media-enabled cooshmobile has crossed my mind (also I am less likely to fall asleep while driving).

I'd have to say mid-30s, at least for a road bike ridden on CA roads. Sometimes the really big ones can get a little bouncy. Not quite 'dodgeball bouncy', but you know what I mean.

I've got 30s on the '81 Peugeot, 35s on the '71 Raleigh Competiton, and 37s on the '74 Raleigh Sports. The 30s on the PPKN-10 are just that little bit too narrow. Not "Man, these things are too skinny!"... more like, "I wish these were 32s."

--Shannon

Well, when I was racing USCF Juniors in 1987, I rode Michelin SuperCompe HD clinchers that were 23mm. They felt fast even when I wasn't that fast of a rider. On the other hand, I was probably 130-140 pounds at the time and riding roads in suburban New York state that were generally in pretty good repair. The guys doing big rides in the touring club were generally on 700c 28mm tires or even 27x1.25" tires, on those same roads.

Now I'm 52, not racing, about 200 pounds or a little less, and am riding roads that aren't nearly as in good shape. So it seems entirely reasonable that I'm riding 32mm or 35mm tires. You are, of course, welcome to ride the tires that you like to ride.

As one piece of anecdotal "data", I had a loop in West Seattle that I liked to ride that was a little over 20 miles. It went around the tip of Alki beach and had some long stretches where you didn't have to contend with stop lights. One season, I decided to keep track of the times on that course with different bikes and tires. No surprise to me, the fastest was the carbon fiber bike with 28mm tires, generally around 1:15. Not too bad considering the stop signs, traffic, and hills. The titanium bike with 25mm tires and the steel bike with 32mm tires were a few minutes slower; say 1:18 to 1:20 on average. The steel "randonneur" style bike with 650b 42mm tires was a few minutes slower than that. It felt slower, but wasn't much slower in actual timing. I didn't try to measure power output or wind or control for stopped time, so it's not really a good study. And there was about equal variation ride-to-ride in the times of a single bike and tires (although there was a general trend faster over the season as I gained fitness and the weather generally improved) than the variation between the average times across different bikes and tires. But it did prove to my own satisfaction that there really wasn't much of a difference in actual times, so the point that I took from it was that I should ride what I enjoy riding and not worry about the bike or tires seriously affecting my riding speeds.