I've an X-lite/Raleigh Ti bike from ~1995 that has been in the garage for the last 10 years and is now getting some attention. I always loved the light frame so I'm bringing it into the 21st century with new XTR mechs and shifters, Raceface XC SL chainset, etc. Aiming for something ultralight for XC rides, and a bit retro mixed with ultra modern.
The only part I cannot easily upgrade is from vees to discs. There are one or two bolt-on options available which attach via an adjustable arm to the canti brake boss, but I've never liked the look of them and I'd be worried about the ti frame flexing at the single brake mount under load. I could weld to the frame, but this isn't the easiest, and it seems a shame to permanently mod the frame.
So this weekend I fired up the CAD on the laptop and designed a strong bolt-on IS disc bracket that clamps onto the drop-out and rear stays. It is designed to spread the load through the main tubes with a big footprint contact area, and also butts up onto the dropout for added support. It stiffens the whole lower corner, so frame flexing shouldn't be a problem. In aluminium the weight is 135g for this Mk1. It uses titanium M4 socket heads to clamp the halves together.
The hardest part has been sizing it to fit the stays in 3D space. I eventually resorted to a combination of vernier measuring and taking high-res pictures in 3 planes, then scaling the images to known dimensions and measuring the tube centres and X,Y,Z locations.
Before getting one machined I'm checking the fit - I have a 3D printer so I'm doing a 3D print run just now. It should be ready in the next few hours. If it turns out ok, I'll post a few pix so you can see how the project is progressing. And if it fits the frame perfectly, I might even do a quick ANSYS run and look to thin things a little to save a bit of weight on a Mk2 before machining one for real.
Its taken quite a few hours to get this far, and I'm not planning on doing other sizes just now. It is sized specifically for my own bike geometry, which is medium, but if it works would anyone else be interested in a bracket too? I've a pic below of the rear drop-out (sorry about the quality, it was taken just now on my phone).
Also, as part of the rebuild I will probably have some barn find components up for sale, assuming the above bracket works as planned:
Middleburn RS-DH 175mm cranks (in blue, good condition)
Pace RC36 EVO II 100mm carbon / magnesium forks (VGC)
Ultra rare Goldtec 8 speed aluminium and titanium rear cassette (mint condition. Trial ridden once for ~10 minutes so light chain marks only)
8-speed XT F&R mechs,XT vee brakes, XT vee levers, LX shifters
File comment: Mk1 bracket
RY-001-1002a.jpg [ 224.99 KiB | Viewed 1356 times ]