QUESTION: I finally said goodbye to my old Cervélo R3 — a mid-2000s carbon beauty that got me through countless centuries, fondos and more than a few sketchy pacelines. That bike was light, stiff, and tight … so tight, in fact, that a 23mm tire was about all I could squeeze into the rear triangle. Now I’ve upgraded to a new Giant Defy Advanced that can clear tires up to 38mm. That’s practically gravel bike territory, and to be honest, I’m a little skeptical. I keep hearing that wider tires are “faster and more comfortable,” but I’ve also seen those fat tires and they just look slow. I still do fast group rides and don’t want to handicap myself. So here’s the question: How wide should I go? Is 28mm the new 23? Is 32mm pushing it? Where’s the line between gaining comfort and giving up speed? I want to believe that wider can be both faster and more comfortable, but I also don’t want to be the guy huffing in the draft because I’m dragging around two extra pounds of rubber. —Ed F.
RBR’S STAN PURDUM REPLIES: For road bikes, 28mm tires do seem to be the new 23s. Most professional road racers are now running 28s. Reportedly, Tadej Pogačar, currently the best bike racer in the world, typically uses 28mm tires, inflated to 55-58 psi. As to whether 32mm is pushing it, it depends on the surfaces you usually ride, the comfort level you want and how the tires affect the bike handling.
In 1995, when I bought my Trek 520 touring bike, it came from the factory with 28mm tires, which at the time were considered needed for the demands of touring with loaded panniers. At some point, I moved up to 32mm tires on that bike, and today, I’m running 35mm tires on it and still liking how the bike behaves.
The shift toward wider tires was driven by research and experimentation, much of it from a team led by Jan Heine at the Rene Herse company, which makes bicycle tires and components. Heine is president of R&D and co-owner of the company. The results of the research were published in Bicycle Quarterly, which highlighted the benefits of wider tires for comfort and performance on various terrains, and especially their ability to reduce rolling resistance, improve comfort and enhance handling.
A key insight from the research is that wider tires, combined with lower pressures, can effectively absorb more of the road vibrations, leading to a more comfortable and efficient ride, especially on rough surfaces.
All of that said, your skepticism about whether wider tires are really faster is understandable. In his book, The All-Road Bike Revolution, Heine notes that while on the bike we cannot feel speed and that what we feel is the vibration of the bike. “As speed increases” writes Heine, “our tires hit more road irregularities per second, and the bike vibrates with higher frequencies. We are conditioned to equate these higher vibration frequencies with greater speed” (p. 45). He goes on to explain that one reason wider tires seem to feel slower is because, rolling a lower pressure, they transmit less vibration, but that when riding timed events, you’ll discover that the wider tires at lower pressure don’t actually hurt your speed.
Regarding your concern about “dragging around two extra pounds of rubber,” Heine says, “Wider tires are inevitably heavier, but not by much, and not enough to make a difference in performance — provided you run supple high-performance tires” (p. 160).
For more detail about the tire-size studies, see “Myths Debunked: Wide Tires Are NOT Slower.”
Of course, typical riding conditions in your area and even your personal preferences can affect your tire-size choices. If you like the feel of riding on narrower tires — or even if you just like the look of skinny tires — there’s no rule that says you can’t run them. Bicycling always has space for individuality. Regarding your decision about tire size, see Heine’s “How Wide is Right for Me?”
Stan Purdum has ridden several long-distance bike trips, including an across-America ride recounted in his book Roll Around Heaven All Day, and a trek on U.S. 62, from Niagara Falls, New York, to El Paso, Texas, the subject of his book Playing in Traffic. Stan, a freelance writer and editor, lives in Ohio. See more at www.StanPurdum.com.
Wider tires require a wider rim to properly support the tire. Otherwise you’ll have to over-inflate to stop the tire from squirming around. Narrow rims with wide tires will also incur an aerodynamic penalty.
Right size is best. A mid-2000 model bike probably has 17mm wide rims for which a 23 or 25 tire would be the max size.
Caliper brakes will also limit you max tire size.
Another limit may be seat stay dimensions. I run 32 on my newest endurance bike but can’t widen the stays on a early 2000s carbon frame so it runs 25. I have a custom Land Shark steel frame where I could widen the stays, but that would wreck the paint so why? It’s my version of a classic sports car.
35 mm on my Waterford Rando, 32 on the Gunnar Touring, 32’s on the two vintage bikes. I would go to 35 mm if I was willing to either remove the fenders or put wider fenders on especially on the Gunnar with its stiff disc fork. Comfort is king. Love the extra rubber on fast winding descents.
I am 77 and have been riding nothing but a gravel bike for 5 years now. I intended to have two sets of wheels for road and dirt, but after riding on Rene Herse 48mm slicks I see no need for anything else. I can maintain 16 mph on group rides with 40 psi and enjoy much better ride off pavement with 30 psi on trails. I run TPU tubes and went with 650 wheels to maintain proper geometry with the larger tires. I am sure the larger tires are much faster on dirt as they float over most surfaces and obstacles. When encountering a pothole on the C&O requires crossing the grassy medium I hardly notice it. On chip seal you will hear it but won’t feel any significant vibration. This bike is by far the quietest bike I have owned and I think the lower pressures are a significant part of that by reducing vibration.
Thank for all these comments.
I am also 77, and for 7 years have been riding an ‘all-road’ designed bike. I added relatively wide (25mm) internal width wheels and high quality supple tires (sold by Rene Herse). I started out riding 28mm/32mm (front rear) and have steadily increased the size of tire and now use 35mm front / 38mm rear.
I installed TPU tubes in my ReneHerse slick tires, and pump to between 50-60 psi.
I have not done tests to determine impact on speed; but I do not detect any change going from 28mm to 35mm width tires EXCEPT for more comfort!
I am only 71, still riding 23, which generally measure about 24. Roll great, feel great, climb easy. No need to switch. Continentals own tests seem to show tires of different widths with proper inflation roll about the same. Design of tire is also a consideration.
Road bike works fine when I encounter some gravel roads, but I try to avoid them. Haven’t had a punch flat in decades. If I want a more comfortable ride, I take out the steel bikes. But a good hard century on a nice carbon ride is still a thrill. Yeah, well, I don’t do Facebook or Instagram either.