How to Convert a Cross-Country Full-Suspension Mountain Bike Into a Downhill Bike

Downhill mountain bike racing is exciting, challenging and requires special equipment. With a few modifications, your full suspension cross country bike can be transformed into a great starter downhill bike.

Instructions

Difficulty: Easy

1. Remove any additional accessories such as bar-ends, water bottle cages, reflectors or lights.
2. Lower your seatpost as low as it will go. You may need to cut the seatpost so that it won't interfere with the rear suspension.
3. Replace a narrow racing saddle with a downhill saddle that has stronger construction and a little more padding.
4. If your frame or fork has any adjustability with its suspension, set it up so that you utilize as much of the travel as possible.
5. Change clipless pedals to either a BMX style platform or a platform / clipless combination.
6. Remove the small and middle chainring from the right crank arm, and move the big ring to the middle position.
7. Remove your front derailleur and front shifter.
8. Add a downhill chain guide to the cranks. This will keep the chain on the chainring when going through rough sections.
9. Change your riding position by raising your handlebar height. You can do this by replacing a flat bar with a riser handlebar, and / or replacing the stem with one with more rise to it. You may also want to go with a shorter stem to put your weight back and provide better steering and tracking.
10. Replace a short travel cross country fork with a longer travel suspension fork, or even a triple clamp fork.
11. Run wider tires for better traction and more bump absorption. Wider tires will also give you better handling over rocks and roots.
12. Replace cross country wheels with downhill wheels. Downhill wheels have wider, stronger rims, and usually more spokes, for strength.

Tips & Warnings

• Some suspension designs will be more suited to downhill riding than others. Bikes with "unified rear triangles," (like Schwinn Sweet Spot bikes, Trek Y bikes and the Klein Mantra, to name a few) lock out when you stand, where as bikes with fully active rear suspension designs work all the time. Every bike will be different.
• For downhill courses that require a lot of pedaling, you may want to raise your seatpost a bit. Try to find a comfortable height that won't block you from getting behind the seat on steep sections.
• If your bike has disk brake mounts, you may want to consider upgrading to a pair of disk brakes. The power of disk brakes surpasses that of linear pull brakes, they work in all conditions, the pads last longer and if you warp a wheel you can still keep going. However, when changing to disk brakes, you have to change hubs and sometimes levers too. It can add up and be expensive.
• If you want to continue to use your bike for other things besides downhill riding, at least keep the triple chainrings, and the front derailleur and shifter. You'll just have to be careful to keep the chain on, and be ready to shift to bring it back over. Make other changes as needed.
• Consider changing the shock on your rear suspension with a shock with better downhill performance. Air shocks are light and great for cross country, but coil shocks are better for downhill.
• Changing the seat height, handlebar position and fork travel will all affect how a bike rides. Be sure to ride your bike and get familiar with any changes before you attempt to race it.
• Doing all of these changes will definitely change a bike from a cross country bike to a downhill machine, but you don't have to do them all. Use your discretion when making changes, and since all bikes are different, some of the changes may be unnecessary or redundant.
• If you want to go with a triple clamp fork, check with the frame manufacturer to see if it is compatible before putting one on your bike. These types of forks put different stresses on the frame's headtube and that can lead to frame failure.
• When changing tires to fatter ones, check for clearance on the frame and fork. If a tire is too wide, it will rub against the frame or fork and potentially cause you to crash.
• Downhill mountain biking is an inherently dangerous activity that can result in serious injury or death. We recommend that you seek proper training and equipment before attempting this activity.