moving up to double from compact, whats required

[scrwright]

Talking 105 stuff here, wanting to go up to 52/36 on my London Road. Rear is a 11/28 and the rear mech is a short one. is it just extra links in the chain or will I also need to step up to a medium cage on the rear?

Thanks

[mikecassie]

Your chain might be ok as it is. I swapped from 50-34 to 52-36 and didn't change chains or do anything other than raise the front derailleur.

[upsidedownmark]

Just move the front mech up. possibly replace the chain, or just be sensible about using both of the largest.. that's it.

[yellowjack]

upsidedownmark said:

Just move the front mech up. possibly replace the chain, or just be sensible about using both of the largest.. that's it.

This really. Slide the front mech up by a distance equal to the increase of the radius of the 52 tooth ring over the 50 tooth compact (and make sure it's correctly aligned front to back). Have a Google about increased chain length too. Plenty of guides as to how to set up for correct chain length but I forget the detail now, as it's not necessary when swapping like-for-like. It may, or may not, need an extra link, but so long as you don't "extreme cross-chain" then it'll probably be OK.

You'd only need to consider a new rear mech cage if you went to a larger inner sprocket on the cassette. Like an 11-32 tooth for example. Cage length is not really closely related to gearing at the front. Shimano Tech-Docs can help with mech cage capacities, etc, if you need them. Or delve into the Sheldon Brown site for help.

[scrwright]

Current chain is 116 hg600 and too short (on a London Road frame). Can you get single links anywhere? If not, will a HG60 11speed do, they are available in 118 link.

Ta

[nammynake]

What's your motivation for changing?

[scrwright]

Better gear range, spend most time in top 4 cogs on the back. Compact was good for getting fitness, legs can do more now, plus will put the compact on another bike I am planning to build.

[yellowjack]

scrwright said:

Current chain is 116 hg600 and too short (on a London Road frame). Can you get single links anywhere? If not, will a HG60 11speed do, they are available in 118 link.

Ta

Can you not split the chain and add in a KMC/SRAM/Wippermann 'quick link' to extend it? If the chain you have is new (or fairly fresh) of course. If it's well into wearing, chains are cheap enough anyway (and that comes from the tightest man I know - I re-use part worn freehub bodies, FFS!).

[scrwright]

New kmc 118 link chain inbound, not much more than twice a set of quick links for a whole new chain