Wise people,

The chainrings on my old Ultegra compact (6650) chainset have worn out and I can't find replacement rings of the right size (I can find them for doubles and triples but not a compact).
Wiggle has the new Ultegra chainsets and the cheapest seems to be the full on double size. Since I live somewhere relatively flat I was thinking of getting that.
Just as I was about to click the 'checkout' button I suddenly thought about the front mech. It's mounted to a thing that's riveted to the frame ('08 Scott CR1). This mount has a slot in it so it looks like I can just move the mech up a bit. Is this the case? Is the mech for a compact the same for a double?
Also, if I'm going from a 50T big ring to a 52 or 53, do I just add one link to the chain per new tooth?

I await the nectar of your wisdom.

–Twirlip

One link per two teeth I would have thought (a 'link' will cover two teeth, not just one).

Can't help with the slotted braze on, although it would take some fairly simple maths to figure out how much higher the mech would need to be (fairly simple and yet i can't quite bring myself to figure it out…).

I'd watch that the front mech isn't designed for a 50 tooth ring, trying it on a bigger ring might cause problems.

The nectar of my wisdom is that "darkside" is a term used by MTB twits.

Otherwise the double will be fine. Just slide the mech up (adjusting the cable tension) and leave the chaim as is – unless you insist on crossing it in the big ring, there won't be any discernible difference from the length.

"Darkside". FFS.

what crank arm length do you ride?

by the time you price up a couple of rings (if you find them), fart around fitting them etc, you'd probably be better off at getting a new compact chainset and sell whats left of the cabbaged one to scrape back some pennies……

I said darkside so less enlightened forum dwellers didn't stray into this thread by mistake and become distressed.

The cranks are 172.5 long.

Helpful comments noted.
Many thanks.

–Twirlip

Save a few more pennies – and do a straight swap? Clicky

That's what i'd do mate anyway…..good luck with it.

There's surprisingly little price difference between the new stuff and the old.
The new stuff is prettier too.

yup…..much prettier if your thinking of upgrading!