Can mountain bikes go fast on the road?

QUESTION: Can mountain bikes go fast on the road? I already have a mountain bike, and I’m comfortable on it, but I plan to join some club rides that are on roads, and I want to be able to keep up. —Harve L.

RBR’S STAN PURDUM REPLIES: Yes, mountain bikes (MTBs) can go fast on the road, but when going head-to-head with a rider of similar fitness and ability on a road bike, the mountain bike rider will be working harder and expending more energy to keep up. When speed on the road is the goal, you will always be at a disadvantage on a MTB.

If you’re just riding your MTB on the road occasionally, the extra effort may not matter to you, but if you are going to be road riding often and want to run with the “big dogs,” you’ll find it helpful to switch to a road bike or at least make some adaptations to your mountain steed.

Mountain bikes frames are made for handling the rougher terrains of off-road riding. Thus, they are built to be extra sturdy — which means they are heavier than road bikes. The geometry of a MTB places the rider in an upright position, which is less aerodynamic than the position provided by a road bike. MTBs have suspension systems, which add weight and subtract momentum as they operate. MTB tires are knobby for good traction on irregular surfaces, but they add rolling resistance on smooth roads. And since MTBs are not designed for road speeds, they are geared lower, so when used on the road, you may run out of gears before you hit the higher speeds.

The type of mountain bike you ride also makes a different. A hardtail or lighter cross country dual suspension bike is going to roll faster than an enduro or downhill mountain bike that is designed for rough downhills and has gigantic, heavy tires.

If you are going to be riding a MTB on the road often enough to make the effort and expense to adapt your bike worth it, you can ameliorate these disadvantages to some degree. Some suspension systems have a feature called lockout, which allows you keep them from operating, and you can change your knobbies for road tires, though probably not as narrow as the ones racing bikes run. You can also change your straight handlebars for drop bars to improve your aerodynamics, but this is expensive since you’ll need different brake and shift levers for the drop bars, and the levers might not even be compatible with the mountain bike specific rear derailleurs. You could even change the gearing, but if you’re going to spend all that money, you’d be better advised to purchase a road bike.

All that said, if you just want to get a feel for group road rides, go ahead on the bike you have. That will help you know whether it’s adequate for that experience. Not all club rides are focused on speed — some have a grading system where, for example, “A” rides are very fast, but “C” rides are less so — and there are even groups that identify themselves as “slow rollers.”

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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.