A sliding dropout on a bicycle is a dropout that allows you the flexibility of being able to move your rear wheel back or forwards.

By doing so, you can increase your chain’s tension or change the handling and feel of how your bike rides.

Horizontal bicycle sliding dropout

Traditional bicycle sliding dropouts are used on singlespeed, BMX, and track bikes. Without a derailleur, it is beneficial to tension the chain without having to remove links.

However, the issue with poorly made sliding dropouts is if they are not tight enough or do not have a strong tightening screw kept in place. One side (usually the side you have the rear cog) can get misaligned, resulting in an unsafe rear tire and inefficient riding. 

Therefore it is essential to adjust and tighten your rear axle on any single speed set up before setting off. Ensure that the rear wheel is perfectly straight before setting off. 

Are sliding dropouts suitable for geared bikes?

You can fit horizontal sliding dropouts to a mountain bike. They offer you some flexibility.

Perfect if you want to convert your MTB to single speed at some point in the near future or adjust the handling and comfort by increasing or decreasing the length of the chainstay. 

Move the rear axle forward for snappier handling and more playful ride, perfect for popping off jumps and quick cornering. Moving it all the way back gives you more stability and comfort, great for long adventures and touring.

It can make your trail bike feel more like a dirt jumper or your cyclocross racer more like a touring bike. Longer chain-stays also make room for higher volume tires. 

Other Reading


It is a technology that was scrapped in favor of the more stable and reliable vertical dropout. With a vertical dropout, there is only one position where the axle goes (they are also easier to get the rear wheel off without taking off the chain).

Now that we have derailleurs, there is no real need to have a sliding dropout for any geared bike.

However, if you get a good quality sliding dropout with a strong strengthening screw, it does give you some versatility, especially if you want to flip between geared and single speed.