Wednesday, September 3, 2008

Homebrew CX Chain Keeper

I recently changed my cheap Scattante cyclocross frame from a 2x9 to a 1x9.  I had purchased a BBG basguard for use as an outer chain guard but I thought I ought to do something about an inner chain guard, or chainkeeper.  Cyclocross season is coming up fast, so now was the time to do something.  Many people recommend the NGear Jump Stop, but my frame had a little braze-on where that would clamp on, so that wouldn't work.  The braze-on was meant for a front derailler pulley so that you could run a road, bottom pull derailler with a top pulling cable.  I thought, why not use that braze-on? 

I had some aluminum L-shaped DIN rail left over from a work project.

Used the band saw to cut off a chunk.

Used the sander to take the edges and corners off said chunk.

Used the drill press to make some holes.

A zip tie to prevent rotation and give it that custom look.

And voila!  I took it out for a spin to the local park and off some jumps to make sure everything worked.  Couldn't get the chain to derail in the first place so the chain keeper wasn't severly tested.  We'll see if that holds true through cyclcross season.  

Have a Scattante CX frame and need one of these?  I could probably help you out.


Mark said...

If you want to get the chain to jump just find a little techy piece of trail and have it in a really low gear so that the chain is really slack and you might get it to jump.

I tried the Jumpstop but found that it has to be within a mm or two for it to work properly.

Hope it works out though. You should apply for a patent, make a whole bunch and sell them on eBay.

-p said...

Yes, I think that if the chain jumps, it will be on a downhill section of race course where I'm in a high gear and coasting.

My design lacks adjustability, and I'm not sure how many frames it will fit, but maybe someone will want one.