fxdgrjedi

Hello all.

I am interested in doing a little CX riding on my old steel road bike that I use for commuting. It is a late 80's early 90's Atala race frame with Columbus SL tubing, but the funny thing is that it has the clearance for 38's in the front and 32s in the rear. I currently have it set up as a fixed-gear commuter with road tyres on it, riding every day to work and back.

Since I never have time to MTB anymore I was thinking of hitting the trails as part of my before/after work commute on the Atala. I am seriously in need of some singletrack.

I have most of the parts that I need (i think) to make it into a SSCX frankenbike. Tektro levers, 39t chainring etc. The only thing that I am stuck on are brakes. Without welding on canti mounts or disc tabs, what is the best way to go about getting brakes on with clearance for fat tires? I have seen people use old center-pull brakes that mount in the regular road brake "hole" Would these give me the clearance I need vs regular sidepull road calipers?

Oh, and what is a good SS gearing for trail riding?

Thanks!

fietsbob

Start with 2:1 Chainring:cog, with the 39, a 20t freewheel.

Brakes , measure reach..
center line of the mounting hole to the center of the braking track.

then shop the dimension.

Andy_K 

Probably. This is a picture of my old '77 Gitane's rear brake.



That bike started with 27 inch wheels and I converted it to 700c, so I had to use some extremely long reach center pulls.

Depending on your bike, you may be able to achieve the same result with long reach caliper brakes. I think the real determining factor is how far your tires are from the brake bridge. Long reach calipers won't really help if you don't have a long reach to the rims.

The 2:1 ratio fietsbob is a commonly accepted starting point for CX racing. For just riding relatively tame trails you can probably use something a bit taller if you like, maybe 39-16.

VonVelo

Paul Components makes a ridiculously sweet center pull brake that works with a road style brake mount. For gearing a 42x16 is pretty stout but if you're not hitting loads of climbing it's not bad. Gearing really depends on the terrain and how much pain you're willing to suffer through - :-)