QUESTION: I have a 2019 Scott Addict 30 endurance bike that came with 700×32 tires. I just upgraded my wheel set and I want to switch to 700×25 tires. Is this a good move? I didn’t know if there was a “minimum” tire width for specific road bikes? – Chris
RBR REPLIES: There’s not really a minimum tire width for a road or gravel bike, but there could be a minimum tire width for a particular wheel set. There are some higher end wheel sets out there from brands like ENVE that require a minimum of a 28mm tire, because the wheels themselves are wider and you need a certain sized wheel to safely stay attached to the rim.
So the first thing I’d do is look up those exact wheels and see if they require wider tires, just in case. You could probably call Scott and they’d know if your bike shop doesn’t. If the wheels are not tubeless and are just regular hooked rims, then it’s a fairly safe bet the smaller tire will be fine. It’s typically just the expensive, wide hookless rims that have minimum tire size requirements.
The truth is though, that most road riders are trending toward riding with wider tires these days than narrower. In fact, many roadies would be jealous to hear that you can fit 32mm tires on your bike, because many older road frames are limited to 25mm as the maximum, and some are even limited to 23mm tires. That’s because 10 or 15 years ago, narrower tires were the trend and thought to be faster than wider tires.
Even the pros are riding 28mm tires sometimes today, because they’ve discovered that the extra air volume and contact patch from the wider tires provide more comfort and traction that is worth the slight weight and aerodynamic penalty.
If your current 32mm tires are a cheaper level tire, then they could be very heavy and slow. So you’ll probably ride faster with 25mm tires because they will be so much lighter. But many of the top level clincher tires like the Continental GP5000 go up in size to 30mm or even 32mm. So you’d get a light and fast tire that also has good air volume for comfort, and a big contact patch for cornering.
I personally ride GP5000 tires that are 32mm on one set of road wheels (which do not feel any slower on fast group rides), and ride 28mm tires on a different set. I don’t typically ride 25mm tires anymore.
Readers, what do you say? What would you do in his situation?
I have the same bike and felt the same. My Trek with 28mm is noticeably lighter and faster with less drag. I kept the 32mm on though as the tires are definitely more robust and have better grip in the rain.
If the tire and rim are properly matched then there is no aero penalty for the tire sizes in question. You get an aero penalty if the tire is wider than optimum for the rim width.
I’m in the bigger is better camp. 32’s tubeless at 60 psi. Not a racer anymore just enjoy the ride.
Wider tires allow lower pressures which means better traction, more comfort, and longer tire wear. The downsides are higher weight and a tiny aerodynamic penalty. The added weight is also pretty meaningless: an additional 110 gm would result in a o.o25 mph speed penalty on a 6% grade climb.
Rene Hearse has lots of data about tire size, weight and aerodynamics. Basically, non of it matters, it’s more about the suppleness of the tire.
I am riding Rene Herse 650×48 slicks on the road and off. Don’t notice any speed penalty within my range. I am 75 and rarely going over 20 mph. Comfort and grip are wonderful. Max 40 psi, 30 off pavement. Jan just did a brevet on 54s because his other bike wasn’t ready.
I’m no expert. I ride a 32mm at 90psi in the summer. It has little tread pattern to none on the centre line. My winter tyres are 23mm. Decent tread, forward and braking traction benefits. I ride them at 110psi too. So rock hard, thin tyres. I dont corner hard on them, the road tends to be damp in winter. My strava stats suggest I’m always slower on the treaded tyres, some extra drag may come from long sleeves and legs but not uphill.
90 psi is a lot of pressure for a 32mm tire. I weigh 170lbs and use 65 psi in the rear and 45psi in the front.
For professional racers, years ago, narrower tires and highest pressure possible were thought to be fastest (lowest friction). Then an engineer did an experiment with a professional team and discovered that wider tires at lower pressure were actually faster (slightly more resistance/friction but more power to the road). Professional riders now all ride wider tires at lower pressures.
For the recreational rider, (and professional) wider tires at lower pressure are more comfortable.
I ride 25 mm GP5000, so far so good for my new custom made steel road bike, I tried 28 mm but don’t see any difference, so get back to 25 mm in the following tire set
Interesting comment, Sergio. I am currently riding 28mm GP5000 on my steel bike, a Ritchey Logic, but will probably go back to 25mm. I’m wondering if frame material impacts the optimum tire width. That is, the main reason people move to wider tires is for increased comfort. Wider tires absorb more of the impacts from road surface imperfections, especially the high frequency vibrations. But, as we know, steel frames offer a more comfortable ride than many carbon frames, specifically because they absorb the high frequency vibrations better than carbon (or aluminum). So maybe optimum tire width for a steel bike is narrower than for a carbon bike? It’s an interesting idea, and I invite others to comment.
I’ve tried 28-32 on my Ti bike and I prefer the 32. Any difference in aero is insignificant and the 32 does have increased comfort.
The newest studies that take into consideration you are riding on a less than perfectly smooth surface. If you look at the stats on the differences between 23, 25, 28 and 30 widths, the differences are usually less than 2% for rolling resistance. I would suggest that 90% of the readers here could never tell the difference. Wider tires made to the same thickness will be heavier, that weight is on the rim maximizing the rotational inertia of the wheel. This leads to a slower acceleration if all other factors are equal. But when was the last time you were in a race and lost by 0.25 seconds? I promise, from personal experience, the smoother ride of the wider tire wins the popularity race.
I switched my endurance bike from 25mm to 34mm a couple of years ago. It was like taking a percocet. Soo much more comfortable! The bigger tires and slightly lower pressure eliminated a lot of low-level buzzing. And I didn’t notice any difference in speed.
Your bike is Addict-ive enough without needing percocet to be comfortable.
(Just so you know, I only took percocet once, prescribed by a dentist, and never before riding.)
I have found 25mm tires and 28mm tires to ride faster than the 32’s. If I’m on a longer road ride I prefer the 28’s because at a lower pressure (70 to 75psi) you don’t feel every crack in the road. I use the 32’s for road/trail/gravel riding. The 32mm Conti 4 season tires are heavier, have a nice tread and are resistant to punctures. At 75psi those tires are very comfortable. The 28mm Conti 5000 SLR, tubless, are a dream to ride. Superb handling. The problem is I get punctures. When that happens I loose both sealant and air. Apparently the CO2 in inflaters are not compatible with sealant. So it’s a good idea to carry a pump. You can use a tube in a pinch with a tubeless tire, but the sealant gets all over the place. No fun there. Once the tubeless tire punctures, I just don’t trust the tire anymore and those tires are $100+. Last year I spent $400 on tubeless tires. Now I’m switching to back to use 28mm Conti Hardshell tires with tubes in them. Two of them cost 100 bucks. They are more resistant to punctures and can take a beating. I ride about 3,000 miles a year.
Yes, you described my same problem with road tubeless. They work great most of the time, but then you’ll eventually get a flat anyway and they won’t seal up. Then you either have to keep adding air to try and get home and try to put in more sealant and see if it will fix the problem. Or you are stuck with a disgusting sealant mess out on the road, trying to put in a tube. I loved tubeless at first, but then I went through a run of flats and tires that wouldn’t hold air reliably anymore and I mostly use tubes now.
Funny enough, I’m testing some Gatorskins right now to see how bad they are compared to GP5000 because I felt that other cyclists are probably also interested in just avoiding flats period, and they are surprisingly not as terrible as I expected.
Earlier this year I returned home with 4 thorns in my front 32mm road tubeless tire. I only noticed the thorns when I was wiping down my bike as the punctures all sealed as I rode. I got a little leakage when I pulled the thorns out, but that sealed immediately.
High pressure, low volume tires do not work well with sealant and I wouldn’t recommend tubeless for tires smaller than 28mm.
Not all sealants are created equal and I’ve used some that perform poorly. My current favorite is Truckerco.
UTube article on the Giro they are almost all riding 28s this year
Modern bikes [should] have been redesigned (lowered BB, to oversimplify) to optimize handling, performance, and cornering clearance, for accommodating the wider tires they’re now coming with. While the rim will likely accept a 25mm tire perfectly well, beware that lowering the bike (closer to the ground) by a nominal 7mm may affect how the bike rides and peforms by more than simply having narrower high pressure tires. Depending on your experience and sensitivity, some may argue the difference to be insignficant. It is however enough to justify consideration in the design of a bike, and selecting tires to optimize handling and cornering, etc. As others have suggested, wider tires are fantastic, and arguarbly just as fast, as long as you’re riding great quality supple tires.