Can a mtn bike be turned into a fast road bike?

Question

I want to create a fast road bike, but still want flat bars, full suspension, and (good) disk brakes. Will this type of conversion be competitive in races if I change the gearing? (I know bike stores actually sell bikes like this, but the ones I've seen have been really cheap.)

Answer 1

Sorry, but even the strongest riders are going to be at a serious disadvantage on a mountain bike in a road race.  Here are the issues.

First, your bike is going to be heavy.  You need to realize, even in CAT 5 races, folks are toeing the line with sub 15 pound road bikes.  In general, mountain bikes are optimized for robustness.  Road bikes are optimized for weight.  You can spend thousands of dollars to lighten up your full suspension bike, but realistically you probably can't get it too much below 25 pounds.  Therefore, unless you have an incredible power to weight ratio, you will start out with a severe disadvantage.

Secondly, your bike suspension is going to be robbing your power.  To get all of your power to the pavement, you'll have to lock out the suspension.  If the suspension is locked out, why have it?  Riding on the road with your suspension locked out, it is like carrying a big anchor.

Thirdly, flat bars are OK on trails where your rarely get enough speed for wind resistance to be a significant factor.  On the road, though, wind resistance is a really big issue.  Most CAT 5 races in our area average in excess of 20mph.  At these speeds you are spending much more energy moving air than moving your bike.  In fact, published research shows the single greatest factor in road races is riding in an effective aerodynamic position.  This means you've got to be down on the drops with a flat back.

Fouthly, beside the fact disk brakes are not allowed in road races, why would you ever them on a road bike?  Disk brakes are heavier.  Rim wear on a road bike is not a significant issue like on a mountain bike.  You won't be spending enough time or energy braking to appreciate the beautifully modulated feeling of hydraulics on a road bike.  (If you have mechanical disks, you don't even have that slight advantage.)  Furthermore, very light weight road brakes provide more than enough stopping power.

Finally, your bike's drive train (chain, chainrings, cassette) are an expensive replacement.  Assuming you don't have to replace your crankset to put on bigger gears, you'll drop at least $200 to get the bigger gears you'd need to hang with the roadies.  Seems like a lot of money to spend in the futile effort to be competitive on your mountain bike.

If you want to get into road racing get a road bike.  You'll be far happier with the results.  Also, if you are like me, you'll find you enjoy the mix of road riding and mountain bike riding.

Hope this helps.

Answer 2

Id doubt it. Disc are heavy and unnecessary. You dont need to dimestop on the road. The frame is also tons heavier and has no purpose on the road. Suspension is heavy too. Get some padded bike shorts and youll be fine.

I'd be surprised if it will make you remotely competitive. You are carrying a ton of extra weight.

Just get a roadie. You can find good ones on ebay for $500 shipped.

Answer 3

No, a converted mtb will not be competitive (unless you are Alexander Vinokourov and you're stoked)

Look at a Scott or Jamis or Bianchi road bikes for around $500-700 or a Schwinn Fastback (not the big box Schwinn!).  Those are very reasonable, very serviceable road bikes.

Try the Schwinn Peleton, or any number of bikes in the $900-1,200 range.  If you have the motor, they will get you there.

Or look around for a used road bike.  Lots of good ones out there running 9-speed gruppos.  Grab one with a well-made, good-fitting frame, and upgrade the gruppo later if you want.

It's not quite all the bike.  I've seen guys be competitive with downtube shifters and 6-speed clusters.  The motor on the bike makes a big difference.

But the mtb still will not cut it.  Even Floyd Landis bought a road bike for his first road race.

Edit:  In reference to MR's statement, bar ends on a mountain bike are not allowed, not even in cyclocross.  I'm a USAC official, and that's not just an inference; it's in the rulebook.

Answer 4

No, you won't be competitive. The bike you want to use has numerous non-competitive aspects to it. Also, this type bike may not be allowed in a road race, check with the race officials.

EDIT: Zinn... I didn't think of that. I was thinking disk brakes for sure and maybe suspension.

Answer 5

No.  I don't think you can get competitive in the road area using a mtb frame and suspension.   I don't think you need disks for road use, and probably suspension, for going fast on pavement doesn't really help.  Avid makes some disc brakes for road bikes, but the frame must be able to use them.

I think you could change the bars to flat on a road bike, I don't see why you wouldn't be able to.

You could make a nice bike for pavement based on a mtb, but not one for racing.  You can't tune a Jeep Wrangler to compete in Daytona.

Answer 6

I have road tires for my mtb and it made a world of difference for on road riding, but it is no where close to even being competitive with a road bike. Not even if the guy on the road bike was 300lbs and out of shape. MTB's are heavier and the geometry of the bike is setup different. They are made for power and maneuvering in tight situations. Look at fitness bikes. You will lose the full suspension, which only takes away from you pedaling force anyway, but you will get straight bars and a bike similar to a mtb in feel on the road. Disc brakes are heavier and the main purpose of them is to maintain braking power even when your tires and wheels are wet, dirty, or muddy. Look at road bikes, they have the lightest brakes you can get. You don't see disc on them.

Answer 7

no. the geometry is different from a road bike, so immediately you're at a disadvantage. disc brakes are illegal in road & cyclo-cross racing (UCI rules). even the best XC full suspension rigs will not pedal as efficiently as a rigid road bike. flat bars do not afford you the aerodynamic positioning of drops. your bike would still be 2X the weight of the others, and you'll be racing guys that train religiously to race! if you want to do road racing, get a road bike. you can get a cat 5 worthy rig for $800-$1000. less than the cost to rebuild your MTB with lighter rims, new drivetrain, etc.

Answer 8

Even if it would work, which it won't, as explained by the other answerers, what would you do when you wanted to go singletracking?  Put hours into swapping the old parts back on?

The serious cyclists I know have several bikes for different purposes.  At a minimum, you need a good road bike, a good mountain bike, and a general purpose bike for commuting or just getting around.    If you're really serious, you would also need a tri-bike and a cyclocross bike to compete in those sports.  

You wouldn't take your daily driver Corolla to the drag strip or road course, would you?