Mod retro conversion....the ultimate 80s trackie.

[Tootyred]

Obviously the frame has no canti mounts to match the forks.....well this is a "mod retro" conversion, so i need to deal with that.

I've mocked up some bosses onto the rear and worked out they need to be pretty far out onto the frame, due to seat stay shaping.

I was hoping to possibly use v brakes, but tbh, they are going to be a harder to live with as the pads are naturally closer to the mounts than cantilevers due to their design. The problem with this is if the pads dont clear the frame and fork when swung backwards, you have no chance of removing the wheels without deflating the tyres.......

So cantilevers it is......plus its more retro.!

I started with m732, but i think with the very compact rear geometry and short chainstays, im going to be kicking those with my big feet. So it may be m735 compacts instead. Or possibly some xtr m900!

 

[Takingabreak]

Are you sure about canti brakes? I don't remember my "trackie" having canti brakes back in the day. To be fair, I don't remember it stopping particularly well either

 

[Tootyred]

I don't have any caliper rim brakes...never being roadie.

Yes....cantilevers is a massive upgrade ! Got to have a bit of bling in your life and treat yourself to the latest tech.

 

[Tootyred]

Ive been looking at cranks today. My go to was a xt m730....i have a couple knocking round. The idea being to use a 113mm bb ( should be 122) and then put the middle ring on the outer position. This bb swap effectively moves the ring 4.5mm inboard.

Ive done it a few times before, it looks pretty neat, but the chain line is still not really quite right, but its only 5 mm out.....one gear.

However, the short chainstays on this bike is exacerbating the issue. You could go with 107mm, but that raises another problem as you have chopped the q factor down to 157mm and being tall and wide hipped.....i need my q!. Thats just too narrow.

So solution B is to go with xtr m900. On a 107 bb and put the ring where it should be. Not as neat, but it keeps the q factor as per factory and gives the perfect chainline.

Btw, the easiest way ive found to measure q (thanks for holding it for the photo glamourous assistant) is to put both cranks on in the same orientation....ie Not 180o apart....then measure.

 

[Tootyred]

Something else I've discovered is that the head tube stops for the gears are a pain the the arse! They are threaded amd take a screw in adjuster.

Problem is with them in, there is so little cable flex, that the gear cable actually puts the front brake on when the cantilever cable hits it.

Oh well...looks like a bit more brazing needed!

The final job today was just to make sure that the frame is reasonably straight, especially the hanger as it really looked a bit on the piss to me. It was....so that now put back...it was a good 15mm out of line at the rim....it must have shifted gear horribly.

 

[Retrorockit]

Ratro? Roaching out a new frame with old parts.