Friday Group Ride #338

Friday Group Ride #338

When I first started riding mixed-terrain, what some people call gravel but bears no resemblance at all to gravel, I mounted a pair of 28c tires on my road bike and off I went. Occasionally, especially in Fall, I found myself wanting for traction, but I pounded my way down a lot of dirt paths, snaked through not a little rooty single-track, and hung onto the back of some pretty fast moving packs when everyone else was on ‘cross bikes. I was pretty happy with that.

Eventually I built a new bike for this type of riding, and I opted for more tire clearance, Mainly I run a file tread 32c tire on that bike, but sometimes I opt for 40c with more tread. The closer we get to the snow flying, the more rubber I like to have on the road/dirt.

In the meantime, road tires are getting wider. I don’t know anyone who rides 23c anymore (remember 19c?). 25c, which was where I thought things would settle, quickly morphed to 28c, which means that people I ride the road with show up on tires I used to think acceptable for single-track. I still run 25c on my road bike, for whatever that’s worth. I need all the help I can get.

Lost in this mania for larger and larger tires is compatibility with various forks. Most road forks aren’t actually wide enough to fit 28c, and those that are face the further challenge of wider rims (everything is growing) pushing the bell of the tire still wider. I have seen 28c tires measure 31c on a 25mm rim.

This week’s Group Ride asks, what are you rolling on the road? 23c? 25c? 28c? Wider? Have you come up against the hard boundary of fork spacing? Do big tires interest you? Or are you more of a skinny rubber traditionalist?

, , ,


  1. Craig P

    I’m riding 25c tubeless tires ( currently IRC or Schwalbe ) on HED Ardennes + wheels, which blows them out to 28mm! Great ride on the road. Really helps on chip seal or broken tarmac and high speed.

  2. Scott G.

    26mm on the ’86 Ellis Briggs, deflate tire to mount wheel, really tight.
    28mm on the Kvale, designed for 30mm in 2005
    32mm on the Ebisu AP, might try 35mm
    28mm on ’54 Claud Butler, don’t think a 32 will fit.
    28mm on the ’37 WJ Hood, maxed out there.

    Go fatter in the winter, bad roads and riding in the dark, make 30s nice.

  3. Chris G

    Would like to try 28c, but no room between the Seat Tube and the back tire. 25c is super close already. Riding a Giant TCR Adv SL. So faced with a new bike purchase or just, tire envy for now..

  4. AusTex

    I’m riding 35mm tires on my Calfee Adventure @70psi. Took a little getting used to the cushy ride but on chipseal it’s quiet, on smooth asphalt it’s silent. Especially nice is if I have to cross some grass or soft dirt or gravel it’s no big deal. Potholes are easier and less jarring too.

  5. Arnie

    I tried Michelin Pro4 Service Course 25s on my Colnago C59…actual measurement closer to 28. Rubbed on my fork with ANY grunt picked up on wet roads. Rubbed on the bottom of my reR brake in the same conditions. Back to 25s for me. BTW, running Specialized Renegade Controls on the Fargo.

  6. Donovan

    ’77 Eisentraut Model ‘A’- 28mm could go to 32mm
    ’81 Trek 710 35mm w/fenders-Touring and commute bike
    ’83 Specialized Expedition-35mm w/fenders
    ’90 Davidson custom-28mm
    ’04 Rivendell Rambouillet-28mm w/fenders- maxed out
    Where I ride there is a lot of chipseal, I run 60-65 psi on the 35mm and 80-85 on the 28mm. I used to run 23mm but just got tired of the flat tires and the jarring and vibration.

  7. Alan

    Been riding dirt roads in the fall/winter for 10+ years, originally on a MTB. Built a cross bike to see how that would work and–as you stated–put bigger and bigger tires on it. In my defense, the sandy roads of NW Florida beg for more volume, even in the winter.

    On my carbon frame it ended up being the seatstay clearance that was the limiting factor. I had to shave down the side lugs on the 40 mm tires I bought (DOH!) but the 40mm cleared the front fork. Guess I just got lucky on that one.

    I’m a big guy so I was riding 25mm on my road bike when they were hard to find–really helped with comfort and pinch-flat resistance. Riding 28mm now and they barely clear the seattube on my Scott road bike.

  8. Damian Bradley

    I run Schwalbe G-One Speed 30c tubeless tires on wide Boyd Altamonte rims that put the tire to about 31.5mm. I’ll be moving to Compass Bon Jon Pass Extralight 35c tires, which weigh in at about the same as the Schwalbe. Bike and fork have lots of clearance, a Brodie Wolff stainless steel “Adventure Road” bike: road geometry (not cx) with lots of clearance. Brilliant for my riding.

  9. Michael

    I have 23 Michelin Pros on my “light” road bike and usually run 28 Conti 4 seasons on my travel bike. Sometimes I put 32 smooths, sometime 32 cross tires, on the travel bike, depending on my plans. My “light” bike is limited in the rear – maybe a 25 would fit, but it would be very close and I worry about Arnie’s problem. Still, I have that bike for pure road, and ride the travel bike if I am feeling more adventurous or riding rough pavement.

  10. Jeff

    I’m running secteur 28’s on DT Swiss RR440’s, they measure out at around 29mm. Fit fine on my IF crown jewel and eddy merckx corsa strada, a little tight on the rear brake on the Eddy. Love those tires, I also have some conti GP4000 25’s on Pacenti SL23, those are around 27mm. I thought those were the best until i tried the Hutchinson’s, now just waiting to wear them out so I can switch.

  11. AG

    I ride 26mm Specialized Turbo’s and with a slightly wider Easton wheel they measure about 28mm. Super nice ride. I mounted new Conti 23’s a while back but the ride was noticeably harsher, so I’m not going back to skinnies. I would like to try 28mm (which would probably measure 30mm mounted) for rougher roads but I don’t think they will get past the Dura Ace brake calipers. If I had disc brakes, I for sure would have a second set of wheels with some 33’s to do some dirt road riding.

  12. Chris

    28s on my road bike, which is an 80s frameset, for years. Wouldn’t want to ride anything less (and yes, I remember 19mm tires). But I’ve barely touched that bike this year in favor of a cross bike with 33mm road tires for both road and gravel. Like riding on soft fluffy kittens.

  13. Aar

    26mm S-Works Turbo on one wheelset and 26mm S-Works Turbo Cotton on the other. Both on HED C3 rims so they bell out quite a bit but I haven’t measured. 100psi. I got a few snakebites when I was running 80-90psi. So, I’ll drop the pressure when I get to target weight….

  14. Jay

    I switched to 28s a couple of years ago after reading some articles extolling the virtues of wider rubber. In my opinion they were right. A more comfortable ride and certainly no less performance in terms of speed. I just replaced the 25s on my Spectrum (which will accommodate up to a 35) with S-Works Turbos in a 28 and I am astonished how great they ride. They claim to be fastest and they certainly create that sensation.
    I am open to trying 650b wheels and even bigger tires, i.e. 40s.
    I am sold on bigger, wider tires.

  15. Joe

    There is no such thing as a “28c” tire. There is 700Cx28mm or 700Cx28 as a tire size, where “700C” is the wheel size (there used to be 700A and 700B as well, but they are rare these days).
    When you’re talking about tires that fit a 650B wheel, would you call them “28b” ? I think not.
    If you’re referring to tire width, it’s 28mm.
    Even some manufacturers get this wrong, which is sad.

    1. Doug

      I have WTB Nanos and they say 40c right on the tire. The Challenge Gravel Grinders say 38c right on the tire. The Schwalbe Pro-One says 28c right on the tire.

  16. Jonathan

    I have 28mm schwalbe one tubeless on 23mm rims, measure to ~30mm. Fit easily under fenders on my custom steel roadie, which can take about a 35 without fenders. I don’t race but they’ve never held me back on fast bunch rides.
    BUT: my other bike is a 650b disc all-road type thing which I have 42mm tyres on, and will take much bigger, up to about 47 with fenders. I’ve hardly ridden my roadie since I got it, it’s such a great fun bike to ride. Eats up my commute in comfort and takes whatever dirt/gravel/tarmac i throw at it.
    Fatter is gooder, but not necessarily faster… 🙂

  17. Luigi

    23 tubulars (wide rims, ride like 25s) on the A bike; 23 clinchers on bike 2 as that’s all that will fit. 25 clinchers on rain/beater as that’s all that will fit. Afterv cross season, will throw some 28 clinchers on the cross bike and what what the cool kids now call ‘gravel’ all spring. I think the width pendulum has swung farther than necessary. Ten years from now, the new thing will be narrower tires. 23 – 25 sweet spot for road, 28-30 for mixed terrain. All the rest is affectation. If you really need 38 mm tires, you’re on MTB terrain. YMMV.

    1. 32x20

      It will be interesting to see where we are for road/gravel in ten years. Mainstream MTB tires seem to be continuing the ‘wider is better’ trend, though it’s starting to show signs of finding a sweet spot.

  18. KNR

    700xx32 on the Seven Mudhoney S&S, 700×28 on the Seven Evergreen Pro, 650×38 on the Jeff Lyon, 650×38 on the Naked, 650×42 on the Kogswell, 650×48 on the Elephant, 700×2.1 on the Cutthroat. Haven’t ridden the 700×25 DeRosa in years, Jeff Lyon rules the roost for fast mountain road rides.

  19. 32x20

    I just sold my road bike, as it hasn’t been ridden in months. I’ve been experimenting with a new-to-me cross bike on the road and I can’t find a good reason to keep a road bike unless I’m racing (which I am not, anymore). It definitely gives up some speed, but I’m not sure how much the tires contribute. It’s not bad in a group at 28-30mph, but you do notice it requiring more effort when solo or in the front. I suspect solo I’m giving up 1-2mph on my averages, but I can also jump off on a trail or rough dirt if it looks interesting.

  20. deke

    25s, limited by clearance. Bigger difference, tho, is running tubeless at lower pressure – Schwalbe ProOnes at 5bar. Helps a lot to smooth out all these choppy surfaces.

  21. Lyford

    Started a few years ago with 23s on old skinny rims. Going to 25s on Velocity A23 rims made a huge difference in ride and cornering feel. I now have 28s on one set of wheels, and will replace all my 25s with 28s as they wear out. The 28s just work better on the local roads — rural New Hampshire pavement takes a beating every winter, and you never know when you might end up on dirt.

    28 is the maximum for my current road bike. I’d like my next bike will be able to accept an even wider tire.

    A couple of articles that helped change my thinking about tires:

  22. Dave

    Seat tube clearance on my Lynskey R330 limits me to 25’s which is fine really. North Texas chip seal notwithstanding…….I’m a smallish guy and can adjust air pressure and riding technique for most road conditions. I’ve no interest in riding a road bike off road. I’ve got a mtb with 2.3’s for that.

  23. Ben

    I noticed some years ago that since I was 18, my age (in years) equaled the tire width (in mm) on the bike(s) that i put most mileage on at any time.

    That was until the beginning of the wide tire boom. Since then I first rode on Paselas at 41 mm, and now on Compass Rat Trap Pass (54 mm). The nice correlation has ended; I’m only 39 now. But I don’t look back at neither narrow nor sturdy and stiff tires!

    My studded winter tires are a bit narrower, though…

  24. bicycleego

    25 front and 23 rear as that is the largest I can fit. 25 all around was sublime, but there was bit of rub from the rear tire.

  25. Winky

    23mm @115psi on my summer bike. 25mm @105psi on my winter bike. Roads around here are great, apart from the occasional poor patch. Never felt that I need more comfort. I’ve been riding “mixed terrain” ever since I started riding. The hard 23mm tyres aren’t ideal on looser surfaces, but they’re surprisingly capable. I think people underestimate the versatility of even a traditional road setup.

    Someone mentioned that MTB tyres are showing signs of reaching a “sweet spot”. Not around here. MTBs are becoming increasingly comical in their quest for taller, fatter, softer, wider and heavier set-ups, including tyres. Fat bikes are even appearing on everything from trails to bike paths and the road.

  26. Harth Huffman

    I’ve only run 28mm tires since the mid-90s, when I switched from a short stint with tubulars. I went for a ride with Grant Peterson on Riv prototypes in ’95 and he immediately guided us off the road, beyond a gate to a trailhead. From there, we only encountered mountain bikers with puzzled looks on their faces. That experience changed my riding forever – a road ride meant whatever surface I wanted to tackle. Now, with the quality Panaracer-made tires available from different brand labels, as well as quality 28mm offerings from other brands, riding 28s is better than ever. On my commuter, I upped it to 32mm tires and love it. I believe if I ever have the funds to get a custom bike, it will be a race geometry with room for 32s. I see no downside.

    And that nod to Peterson was intentional: He was leading this very discussion back in the early 90s. (Hmmm, that claim sounds familiar – compact cranks, 650b, etc.) He wrote about fork designs and tire clearance in the catalog, in fact. Count him along with Ritchey and Kostman among those who have long claimed whatever bike they are riding is a gravel bike.


  27. Peter Leach

    I have Specialized Roubaix Pro 23/25c [front] and 25/28c [rear] on 21mm rims on my road bike. No problems with front fork clearance, but clearance to the seat tube on the rear is pretty tight – and clearance to the rear brake caliper is almost non-existent.
    The ride isn’t hugely different to my previous tyres [Schwalbe Ultremo 23 front/ 25 rear or Vittoria Open Corsa CX] but it does seem easier to sit on for longer 🙂

  28. David

    23 Michelin Powers on Stan’s rims at 85psi – they measure close to 25mm. Not sure if anything wider will fit on my Pinarello Paris, but these ride really well.

  29. Calvin

    Commuter Bike – 32 GatorHard Shells
    CX Bike – 33 PDX
    Road Racing- 25 Bontrag R4’s (amazing tire when paired with Ultralight Tube)
    Road Training – 25 GatorSkins

    I don’t buy into the wider & wider tire scheme for road. There is a point of demising return around 26. The whole point is that wider tires have less rolling resistance at the SAME pressure. But the main reason to go wider is to ride with lower pressure…..thus increasing resistance.

    Everyone should experiment with a good set of rollers and various tire set ups. It is easy to see/feel/experience which roll best at various pressures. You don’t need fancy equipment.

    1. Lyford

      Except that surface roughness has a significant effect on rolling resistance. The world is not a smooth drum. if you are blessed with glass-smooth pavement, there may be a good correlation between rollers and road, but that’s not true for everyone.

  30. Michael Fox

    Panaracer 25 Race A on the IF Crown Jewel, that’s as big as will fit. Panaracer Gravelking SK35 on the Lemond Poprad. Next bike will have clearance for 40’s. Here in North Florida, we are blessed with beautiful hard packed red clay roads, and though the IF can handle most of them, wider is definitely the way to go.

  31. Jeff K

    I ride 28’s on Vittoria Rubino’s at 90psi front and 95psi in the rear. 175lb rider with an old Trek Pilot with many miles. Moved from 23 to 25 to 28s for the past 2 years. They fit nicely and I can still get them through the brake calipers inflated. I’ve had fewer flats with the 28s for some reason. The longer the ride, the more I appreciate the width.

  32. Nick W.

    Specialized Roubaix 25/28s, a bit more than 28mm wide on 21mm (external) rims. Lucky enough to have plenty of room for 28s and fenders living in Portland. My next bike is in the works, 650×44 -ish, maybe I’ll use 700×32 if I’m not swayed by the smaller wheels.

  33. Aaron Thomas Smith

    35c Paselas all the way. After making the transition three years ago on a touring bike, I was astounded at the comfort and lack of flats.

    Not to mention the longevity of the tires. I’m could still ride the same set I started out with – and not for lack of miles – if it weren’t for my desire to have pristine skinwalls.

  34. STS

    On “gravel” which is mainly rough fire and logging roads as wide as possible which is 40 mm.
    On the tarmac Schwalbe Pro ONE 25 mm on 17c to 19c rims which makes them 28 mm wide. The great thing with tubeless I (180 lbs) can go down to 50 / 60 psi (front/rear) and don’t have any flats but all the comfort even for really bad roads. It must be a very bad road where using tires wider than that makes you even faster but then you will go slower on the smoother sections because in order to have more comfort with a wider tire you’ll have to inflate them even less. So from a speed vs. comfort compromise I think 28 to 30 mm might be the best compromise for most roads.

  35. Ron

    Oh, where to begin…

    Casati Laser – 25mm Vittoria Corsas (barely, barely clear. If I get even a tiny piece of warm asphalt, as in one “grain” it rubs the fork)
    Tommasini Diamante – 25mm “retro” Continentals
    Van Dessel Gin & Trombones – 40mm Continental SpeedRide for gravel/road rides; 32 mm Vittorias for CX riding/racing (set up tubelessly)

    Commuter #1 – 32 mm Continental Gator Skins
    Commuter #2 – my 32 mm Vittorias after the knobbies have worn off from cx riding

Leave a Reply

Your email address will not be published. Required fields are marked *