Technical FAQ: What’s harder on a bike/wheels — gravel or pavement?
Wear and tear in different riding conditions
I always try to read your column on VeloNews and have your book on bicycle repair, so I am a big fan and always appreciate your viewpoint on aspects of the great machine called a bicycle.
In and around Kansas City, we ride a lot of gravel, (I am a three-time finisher of the Dirty Kanza 200) and have been riding gravel for years … On a lot of rides, particularly with new riders, the subject of abuse, wear and tear on your frame, and wheels by riding gravel seems to come up.
So, the question: What is harder (more abusive, creates more wear etc.) on a bicycle wheel (or frame): riding on gravel roads or on pavement?
I know gravel has rocks and deviations and yes, potholes and washboard surfaces, but a lot of paved roads do too.
I have always thought that traction on gravel is less than on pavement … so some of the stresses of acceleration are reduced, overall speed is less, tires are of a greater volume (more squishy) than on pavement … just seems to me that even with the rocks, dirt and other factors that riding on gravel is not as hard on wheels and possibly even frames as riding on paved surfaces.
Even a pothole, if traveling at the same speed, I believe the stress is less.
Gravel pothole scenario: 35C tire, 50 psi, 18 mph hitting a gravel/dirt pothole.
Pavement pothole scenario: 23C tire, 105 psi of pressure, 18 mph hitting a pavement pothole. I would think the gravel pothole with be a lot less stressful on the bike/wheels.
Anyway, as the gravel grinder scene continues to grow, thought this might be something of interest to others and I personally would like your opinion on it too!
My opinion is that gravel- and dirt-road riding is no harder on wheels and frames than paved-road riding, and in many cases is less stressful on them. I have no test data to back this up, but I have years of dirt-road and cyclocross riding as evidence.
Because of the relentless bouncing around on rough courses, cyclocross seems to me to be harder on the wheels and frame than riding dirt and gravel roads, yet I have experienced incredibly long wheel and frame life while doing it. As you say, I think it is the larger, softer tire that protects both the wheel and the frame.
Other than some occasional wheel truing (and a lot of replacement and/or overhaul of wheel bearings due to mud and frequent washing), in all of my years of riding cyclocross, I can think of only two wheels I’ve ruined, and never in a race. One was snagging the rear derailleur on a spoke, but that failure mode was unique to Mad Fiber due to the way the spokes flex outward under side load and would not have happened with a wire-spoked wheel in identical conditions. I did the same thing to another Mad Fiber rear wheel on the road bike on pavement as well. The other was denting a rear clincher rim running a tubeless tire at low pressure and completely gagging a bunny-hop onto a curb at high speed. This, too, I’ve done on road bikes in the past and wrecked the wheels at least as badly.
The frames, too, take massive abuse to the paint in cyclocross due to abrasion from mud and constant washing. But I’ve never cracked a frame in cyclocross, and I’ve cracked and otherwise totaled many a frame on the road.
I’ve done many years of long mountain rides on dirt roads and have never done obvious damage to a frame or wheels doing it, other than nicked paint from rocks being thrown up.
Consider crashing as well. If you’re racing, whether it’s road, cyclocross or gravel, you’re going to crash eventually. Due to the higher speeds and the other riders almost invariably involved, crashes in road races are much more damaging to equipment than crashes in cyclocross and even in gravel grinding. Of course, crashes are much more frequent in cyclocross and perhaps on dirt and gravel roads as well, so the argument could perhaps be made that the cumulative effect needs to be considered. But other than the occasional derailleur hanger, frames and wheels almost never break in cyclocross crashes; the same can certainly not be said of road racing crashes.
I also think that the two pothole scenarios you pose understate the case, because at the same power output and road steepness grade, the bike will be traveling faster on pavement. I think it is clear that the impact will be higher in the paved scenario.
Due to higher side loads while accelerating thanks to hard tires and road surface, I have to do a lot more wheel truing on road riding. Hitting an unexpected pothole or train track on the road feels like it bashes the frame and fork much higher than anything I’ve encountered off-road in cyclocross and dirt-road riding. And I’ve never had paint get splattered on my frame on dirt surfaces but I’ve had it happen a number of times on the road — with paint that was tough or impossible to remove.
So all in all, I think your gravel grinding is not shortening the life of your frame and wheels any more than your paved-road riding does.