Overmountain bike to downhill bike

Question

I have a overmountain bike (Cannondale Trigger Lefty 27.5) with 140mm travel but I was wondering whether I can make a downhill bike out of it because I really want to ride downhill.

The shock I have in the rear suspension is a Fox DYAD 2 and I'm not sure if I can replace it with other shocks.

Answer 1

No. It's a trail bike. You'd need to add an extra 40-60mm rear travel for a start. It's also perfectly capable of being ridden down many DH tracks as it is - it just might not like the 40ft gap jumps :)

With tongue firmly in cheek, there's a few things you might be able to do, but none of them will turn it into a proper downhill bike. Most of them will void the warranty and/or break the frame!

1. Fit a proper DH fork (e.g. a Rockshox Boxxer) and a direct mount stem
2. Bodge a longer stroke shock into the frame (if you can find a pull-shock that long)
3. Now your head angle and bottom bracket are in a crazy place, fit an angle headset (Works Components or Cane Creek) and/or some offset shock bushings (e.g. Burgtec) to put them back somewhere vaguely sensible
4. Fit some heavy duty wheels (e.g. Hope Pro2Evo + Stans FlowEX, or Mavic DeeMax)
5. Remove the front derailleur, and replace it with a single chainring and a chain device
6. Replace the cassette with a close ratio one and switch to a short-cage derailleur while you're at it
7. Upgrade to 203mm disc rotors and Shimano Saint brakes

Once you've spent all that money, you'll have a complete mess of a frankenbike that doesn't work anywhere near as well as a proper DH bike. As Vorac commented, you're better off buying used. The Specialized Status is a good value place to start looking.

With that said, an angle headset might help make the bike more confident on the descents, without completely ruining it.