The best way to try bike commuting is with the bike you already own. And for some of us, what’s on hand is a mountain bike.
But when you look at those chunky tires, burly frame, and perhaps suspension, you might wonder…
Is it really a good idea to ride this thing to work?
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Here’s whether mountain bikes are good for commuting
Mountain bikes are usable but not optimal for commuting—unless your route is actually off-road. Knobby MTB tires are extremely slow on pavement, so consider swapping them for slicks or semi-slicks. There are also fewer options for the fenders and racks commuters need (but I’ll share some ideas below).
If you’re one of the few who do commute on a dirt trail, then a mountain bike is a terrific choice. For the rest of us, it’s possible to work around the tire and accessory limitations, although it becomes less useful off-road in the process.
What works well?
Comfy riding position
Mountain bike posture is moderately upright, and quite similar to most hybrid bikes. It’s not the bolt-uprightness of a Dutch city bike, but not the neck-cramping lean of a typical road bike, either. This is a comfortable posture for most cyclists—or at least bearable.
Your mountain bike is also very likely to have mechanical or hydraulic disc brakes. When properly adjusted, these have more than enough stopping power for commuting purposes, and they work equally well in the rain. Many MTBs use extra-large brake rotors for even greater power.
In fact, good rim brakes are sufficient for most commuters, so suffice to say you’ll be fine in that department.
Ready for gnarly roads
Some cities are, shall we say, more tolerant of potholes and endless construction. MTBs fare better over these obstacles than any other type of bike. After all, it’s the closest on-street equivalent to the rugged trails they’re designed for.
It’s still safer (for rider and bike alike) to avoid what you can. But if some hair-raising road conditions are unavoidable, then it’s worth
What are the problems with commuting on an MTB?
Tires are slow & heavy
Virtually all mountain bikes have wide tires with deep tread, usually run at very low tire pressure. That adds up to great traction and bump absorption, but it comes at the cost of rolling resistance. (Not to mention several extra ounces of rotating weight, given all that extra rubber.)
Now, traction and bump absorption are top priorities on rooty climbs and rocky descents. But on plain old pavement—or even smooth dirt and gravel—the rolling resistance takes its toll. Compared to street tires, it’s just plain hard to keep up a decent pace.
There’s no free fix, but the solution is often cheaper than buying an additional bike.
Budget option: swap to slick tires
If your MTB’s new purpose is mostly or entirely commuting, then replace the knobbies with slick or semi-slick tires.
Look for a pair that’s close to the width you’re running now, or at least not more than about a quarter-inch narrower. (Otherwise, the bike’s handling characteristics might feel different than you’re used to.) Options are limited for 26″ wheels, but choices abound for 27.5″/650b and 29″/700c.
Better option: a second wheelset
What if your MTB needs to do double-duty, e.g., weekday commutes plus weekend trails?
Nobody enjoys changing tires twice a week. If you have a little more cash to spare, then consider buying a second wheelset to use as a dedicated, slick-tired commuting pair. They start around $200-$300 for something sturdy but heavy, using quick-release hubs with older axle-width standards. High-end rims with thru-axle hubs can easily cost several times as much.
Note: it’s often possible to use narrower tires on larger wheels for city riding. The increase in one offsets the decrease in the other, which keeps the total outside diameter about the same. It’s worth talking to a bike shop first, since there may be other constraints around brake mountain, frame/fork clearance, and bottom bracket height.
Lack of rack & fender mounts
There are basically three essential accessories for commuting:
- You’ll absolutely need lighting.
- You’ll probably need fenders to block rain and road spray.
- You’ll probably prefer a basket or pannier to carry work gear.
Lights are a breeze. Nearly all of them use a rubber strap or screw-clamp mount, which comes on and off in seconds. (Dynamo lights are another story, but they seldom belong on mountain bikes anyhow.)
But things get trickier with the others.
Ideally, fenders and racks screw into little eyelets near the axle and farther up the frame/fork. That gives a rock-solid fit that won’t shift around despite shifting weight and vibration.
However, very few MTBs have such eyelets. That leaves a couple options, which I’ll outline below.
Can you put fenders on a mountain bike?
Yes, but options are more limited due to tire width and the lack of dedicated fender mounts. Stick with MTB-specific fenders to avoid compatibility problems and installation headaches.
If you’re still running knobby tires, then MTB fenders are the only kind that’s wide enough to accommodate them. But if you’re running slick tires for commuting, then you’ll still need MTB or clip-on road fenders. The lack of mounting eyelets is one factor, and you might also have trouble where conventional fenders attach near the bottom bracket and fork steerer.
My suggestion: Look into clip-on fenders like the SKS Mudrocker for MTB tires (buy front and rear) or SKS Raceblade for road tires (buy the pair). They don’t wrap around and protect you as fully as standard fenders, but they’ll mount to any bike up to the specified tire width.
Can you put a rear rack on a mountain bike?
Yes, but you’ll need one that mounts to the seatstays or seatpost. Few MTBs have mounting eyelets, so regular city-style racks will not work.
Racks can be especially tricky to mount on full-suspension bikes, due to moving parts and simply a wider variety of frame designs. Seatpost-mounted rear racks aren’t as strong or stable (since there’s no support from below) but they’re by far the most universal.
My suggestion: Start with a clip-on rack like the Thule Pack ‘N Pedal Tour Rack (available here). It works on many mountain bikes and essentially all road bikes, but you may need to measure your seatstay circumference to confirm.
If you have a carbon-fiber frame, then take particular care. They’re designed to maximize strengths only in certain directions, so the shear force of a rack may risk damage and even void your warranty.
Suspension bob saps energy
A tiny bit of our weight moves up and down while we pedal. On a rigid (unsuspended) bike, this is almost imperceptible. It compresses the tires a few millimeters, and that’s it.
But with front or full suspension, that vertical motion creates a repeated bounce known as suspension bob.
There are basically three ways to prevent or mitigate bob when you’re riding your MTB on the street. From most to least effective, you can:
- If the fork/shock has a lockout lever, then use it!
- If you have adjustable compression damping, then max it out. That’s almost as effective as a simple lockout switch, but you’ll need to reset it to “normal” when you hit the trails again.
- Finally, the least effective but most universal option is to dial up the preload. It’s the least effective of these three, and arguably the most annoying to undo for trail rides, but it’s also the most universal.
So, should you commute on your MTB?
If a mountain bike is the most convenient way to try bike commuting, then by all means do! But if you plan to commute for the long haul, then buy a separate commuting/city/leisure bike if it’s feasible.
No single bike can excel at everything. It’s more fun to have a couple that serve different purposes excellently than one that serves most purposes sufficiently. It’s also more convenient to leave parts and settings as-is, rather than swap them back and forth for commuting and trails.
Secondhand is always an option, so you can even resell it at little or no loss if commuting just doesn’t work out.
Still, if you’re tight on cash or storage space, then a second wheelset (or at least a tire swap) will help your MTB feel more at home on pavement.