It was a complete surprise when I switched from an old steel mountain bike to a brand new, snappy road bike. Every time I sat on the road bike for the first few weeks, it seemed so fast compared to the mountain bike, which felt so slow! So I had to find out – why are mountain bikes so slow?
Mountain bikes are slow because they have larger tires, suspensions, less aerodynamic body position, longer frame geometry, heavier bike weight, and low gearing. They can be faster by making minor changes or adjustments.
We’re going to look at why mountain bikes are slower than other types of bikes, especially road bikes. Then, we’ll look at various reasons why your mountain bike is slow and what you can do to make it faster on the road.
Because mountain bikes are created to ride over obstacles with stability, they aren’t as fast as other types of bikes whose purpose is speed. Let’s look at the details.
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Tires
One of the biggest differences between mountain bikes and other types of bikes is the tires. Mountain bike tires are wider and knobbier than road bike tires and even wider than gravel or cruiser tires.
Mountain bike tires also require lower air pressure. A mountain bike tire is meant to handle large rocks and tree roots to ‘squish’ as it rolls over them so you don’t bounce off. But this type of tire also ‘squishes’ down onto the road surface, which absorbs energy and creates more friction with the road, making you roll slower.
The tires on a mountain bike also have a knobby tread, giving you extra grip in slippery conditions. But when riding on pavement, you don’t need as much grip. The extra tread will slow you down, anyways.
Position
Body position on a road bike is all about speed. You’ll see road riders in a more hunched-over position, with their bodies as flat as possible to allow the wind to pass over them. The narrow handlebars keep their arms in line with their shoulders to minimize the wind their body catch.
Mountain bike position, though, is about balance and control. Mountain bikes have wider handlebars for leverage and a more upright position for strength. But this body position also catches more wind, slowing you down when hitting speeds over eight mph. So the faster you ride, the more your body position affects your speed.
Frame Geometry
The frame geometry of a mountain bike is long for stability, A higher bottom bracket helps them get over obstacles but also makes them a little slower compared to shorter bikes, like race bikes, which can accelerate more quickly and take turns at higher speeds.
Aerodynamics also comes into play with frame geometry. For example, road bikes and some gravel bikes have sleeker and more aerodynamic frame shapes, which means they cut through the wind more easily than bulky mountain bikes.
Suspension, wide bars, and even the shape of a mountain bike’s frame components will catch the wind, slowing the bike down more than a frame designed to be more aero.
Bike weight
Mountain bikes are heavy due to their large tires and heavy suspension. However, hybrid, road, and gravel bikes have thinner tires and lack heavy suspension. Carrying less weight makes mountain bikes faster.
Suspension
A bike’s suspension is meant to absorb the lumps and bumps from the ground. But a suspension system also absorbs energy, so you’ll lose some of the power in your pedal stroke as it gets absorbed by the suspension. The energy absorption by the suspensions makes mountain bikes slower.
Gearing
Mountain bike gears are made to spin easily (albeit more slowly) up hills and offer more torque whenever needed to get over obstacles or accelerate quickly. Big gears that make you go fast are missing. on a mountain bike.
Road and gravel bikes have different gears tailored towards speed and power rather than getting over obstacles. So a mountain biker would need to spin a high cadence on a flat road to keep up with a roadie who is powering along at a more comfortable RPM. Gearing can make it a lot harder to go fast.
That said, it is possible to make your mountain bike go faster when riding on the road. Here are a few suggestions.
How to Make Your Mountain Bike Faster on the Road
Swap the tires
The biggest change you can make is swapping out heavy, fat mountain bike tires for a pair of skinnier slicks (like these ones from Amazon, for example). Unless you ride your mountain bike in extremely technical offroad terrains, you don’t need the extra grip and squish that you find in mountain bike tires. Most paved roads in cities are relatively smooth surfaces. They will be lighter and more aerodynamic.
Lighter tires will reduce the friction between the tires and the road a great deal.
Adjust your tire pressure
If you can’t swap out your tires, you can try adjusting the tire pressure. If you’re going to ride on the road, you don’t need the extra grip and so you can run your tires at higher pressures. Decreasing the friction between the tire and the road will make the bike faster.
Make sure you stay within the recommended range indicated on the tire. If you don’t have a good floor pump with a gauge, it’s highly recommended. You can pick up the BV floor pump on Amazon, which does the job perfectly and doesn’t break the bank.
Lock out the suspension
Your bike’s suspension will absorb some of the energy you are trying to put into turning the pedals. So by locking out the suspension, you’re making the bike a bit stiffer and more efficient, saving energy for pedaling.
Change your position on the bike
Mountain bikes tend to be more upright, but if you can change to a more aggressive position, you can go faster on your mountain bike. Depending on your bike, you might be able to raise your saddle, lower, or even change your handlebars, all of which will give you a more aerodynamic position on the bike.
Change gears
Changing gears is more complicated because not all cassettes and chainrings will fit on every bike. However, changing your gears might enable you to reach and maintain higher speeds with ease.
Reduce weight and bulk
If you can swap your fork for a rigid one, thus removing extra weight.
Also, try to remove any extra stuff from your bike. Bags add weight and reduce aerodynamics, slowing you down.
Make sure your bike is clean
If you’ve been out mountain biking, you likely picked up some mud, dirt, and grime that can slow your mountain bike down. Also, a dirty chain is much less efficient than a clean chain, so make sure you clean it well, too.
