At times, things happen so fast in a rider’s life. For example, what would happen if your road bike cranks failed when you least expected? Can you use an MTB crankset on a road bike and still be competitive?
You can use an MTB crankset on a road bike frame, but you would also have to change the bottom bracket. Notably, most road bikes’ bottom brackets aren’t compatible with MTB cranksets, except for the square tapered bottom bracket.
Mountain bikes have longer and thicker axles than road bikes. As a result, the MTB cranksets use a wider bottom bracket.
Could you be in a hurry? Well, here are five of the best mountain bike cranksets.
5 Best MTB Cranksets Available on Amazon
- SHIMANO Deore M6000 Crank Set – Best for mountain bikes
- ALTUS CHAINSET FC-M311-L – Best for mountain biking beginners
- SRAM S600 Cranksets – Best MTB crank set for budget
- SRAM XX BB30 – Best quality
- GANOPPER 9S – Best overall
Mountain Vs Road Bike Crankset
The axle on a mountain bike crank is twice as thick as a road bike crank axle. This is because the drivetrain on a mountain bike is subjected to more torque and stress than on a road bike.
In addition, mountain bike cranksets have thicker arms that are necessary to withstand the punishment of off-road riding. Road cranks are designed to be as light as possible, and this is achieved by making them thin, which weakens them.
The axle on a mountain bike crank is also significantly longer than on a road bike crank. This is because the chainstay on a mountain bike is much longer than on a road bike.
You can get more details from our earlier article on Mountain Vs Road Bike Crankset.
Differences And Similarities Between MTB Crankset On A Road Bike
The bottom bracket is where you will see the most difference between an MTB and a road bike crankset. Most road bike bottom brackets aren’t compatible with MTB cranksets.
However, there are more diversities between the two chainsets.
1. MTB Cranksets are designed for off-road use, and so they can handle rocks, roots, and other rough terrains that you might encounter on the trail.
2. The axle is thicker than a road bike crankset to withstand the increased torque applied during hard efforts on dirt roads
3. Chainstays are much longer than those of a road bike, allowing riders to pedal smoothly through technical sections of trail without fear of the chain coming off
4. MTB cranksets are available in various sizes to fit almost any rider.
MTB cranksets are not as light as road bike cranksets, but they are more durable. They have thicker axles and arms to withstand the punishment of off-road riding. They are also available in diverse sizes to fit almost any rider.
5. Road bike cranksets are designed for speed and efficiency on paved surfaces. They aren’t as sturdy or as durable as mountain bike cranksets
6. The axle is thin and fragile compared to the mountain crankset allowing the rider to pedal smoothly. At times, road riders will add a chain-keeper to their drivetrain to prevent the chain from coming off
Compatibility Of Road Bike & MTB Cranksets
Mountain bike cranksets aren’t compatible with road bikes, except for the square taper BB. The problem is that mountain bikes’ crank arm lengths and pedal threading are different from standard road bikes.
This means it’s impossible to use MTB cranksets on a road bike by themselves without modifications. However, there are multiple ways to get around this compatibility issue.
1. Using MTB Bottom Bracket Adapter
One way is to use a road bike crank arm with an MTB BB adapter. This will allow you to use an MTB crankset on a road bike, but you’ll lose the ability to use standard road bike pedals.
2. Use A Road Bike Chainring
Another option is to use a mountain bike crankset with a road bike chainring. This will allow you to use standard road bike pedals, but you’ll have to switch out the chainrings when you want to ride on the dirt.
3. Go For Hybrid Crankset
The final option is to use a hybrid crankset, a combination of a road bike and MTB crankset. This will allow you to use standard road bike pedals and offers the most versatility.
Whichever option you choose, it’s important to ensure that the crankset is compatible with your frame and BB type. Otherwise, you may end up damaging your frame or BB.
What Are The Challenges Of Using MTB Crankset On A Road Bike
The MTB and road bike drivetrains are different. Therefore, using an MTB crankset on a road bike would be challenging.
Going by the information on most biking forums, here are some of the most common challenges highlighted by riders.
1. Bottom Bracket Compatibility
Earlier in our discussion, we mentioned that one of the biggest challenges in using an MTB crankset on a road bike is BB compatibility.
First, most mountain bike bottom brackets are wider than road bikes. In addition, MTB cranks have a larger spindle diameter as compared to road bikes.
Therefore, a rider may have to change the road bike’s BB for compatibility.
2. Crank arm lengths
The other notable challenge would be crank lengths. The average length of MTB cranks is 175mm. The longer cranks are ideal for improved leverage.
On the contrary, most road bikes use shorter crank arms. So, if a rider is accustomed to road bikes, the cranks may feel awkwardly long.
Also, for those with knee pain issues, the longer arms may make the situation worse.
3. Front Derailleur Fouling
Due to the difference in bottom bracket widths, the front derailleur on the road bike may not work as intended.
One may use spacers or bottom bracket adapters to work around the BB width difference. However, this would leave you with an unsolved challenge, the front derailleur fouling.
Actually, the front mech would not work, or it would be horrible if it happened to work at all.
4. Added Bike Weight
Without a doubt, mountain bike cranksets take a lot of punishment as they work along the trails. For this reason, MTB cranksets are thicker and heavier than their road counterparts.
If a rider prefers keeping their road bikes extremely lightweight, MTB cranksets may be a disappointment.
For example, the lightest Shimano cranksets weigh 4.41lbs. On the other hand, mountain bike cranksets from the same brand will be about 0.03lbs heavier.
Frequently Asked Questions
1. Can You Put A MTB Crankset On A Road Bike?
You can put a mountain bike crankset on a road bike that would require you to install an MTB bottom bracket. Notably, mountain bike cranksets are wider than their road counterparts.
In addition, the front derailleur and shifter may also require a tweak or two.
2. Can You Use Any Crankset On A Bike?
You can’t use any crankset on a bike because they aren’t compatible across the brands. Compatibility across models of the same brands is also difficult.
The main reason you can’t use any crankset on a bike is that there are many types of bikes and bottom brackets. Since this is where the crankset attaches, you can only use a specific crankset.
3. Why Do MTB Have Longer Cranks?
MTBs have longer cranks than road bikes for increased leverage. The cranks work any other lever; the longer the effort distance, the easier it is to move a load.
Therefore, longer cranks are important in creating the needed torque to scale over hills. However, this could be counterproductive.
4. What Size MTB Cranks Should I Use?
There is no one size fits all MTB crank size. However, assuming that all riders have the same proportion regarding their height and limbs, crank lengths should be 9.7% of their height.
For example, for a rider who is 1.78m tall, the ideal crank size is 172.5mm.
5. Can You Use A MTB As A Road Bike?
Though mountain bikes are made for the trails, you can use them on the streets without any major challenges. All the same, an MTB can’t perform as well as a road bike on the asphalt.
However, replacing the knobby wheel with sleek ones will greatly improve your riding experience on the roads.
Also Read: Are All Shimano Cranksets Interchangeable?
Final Take – Can You Use A MTB On A Road Bike?
Though MTB and road cranksets are not easily compatible, using a mountain bike crankset on a road bike with a few modifications is possible.
Generally, mountain bikes have wider bottom brackets and thicker spindles.
Therefore, if you use an MTB crankset on a road bike, you will need to change the bottom bracket to make the bike compatible. The only exception is the square tapered spindle that is compatible with most road bikes.
However, by doing the modification, you have problems with the front derailleur. Before purchasing a crankset, verifying whether it is compatible with your bike is advisable.