Simple Q I hope – what’s the biggest inner chainring I can fit on a 5700 compact chainset?

Ta in advance…..

At least 46 i think, it’s 110 bcd isn’t it

http://www.spacycles.co.uk/products.php?plid=m2b0s113p1722

Yeah, 110….. so I should have worked that out for myself 😳 It is Monday morning…… Thanks.

Your chainstay may well dictate more than what’s available. Basically an outer chainring will fit so you could fit pretty much anything from 34 to 50 or even 52 though the shift ramps would obviously be redundant.

Clubber – good point as always. Running 50/38 on a 130 PCD ‘standard’ chainset at the moment (38 is about as low as I can go on) – just wondered if I could do the same with a compact, with the option of 37 or 36 inner as well. As the standard chainset fits, should be no problem doing the same with a compact (chainline/axle length is the same?)?

Correct, so it’ll be absolutely fine.

What njee said.

Ace – credit card time…..

Exactly, this is why compact is so good in my view – it opens up far more usable options.

I have a 52/38 on a 110bcd crank on my brompton..

you could with what’s out there do a 56/34 on 110bcd – not sure what the shift would be like though – but then generally youwoul dnot be shifting from one to the other a lot

You’d get horrific chain rub as if the front mech was high enough to clear the outer ring the chain would sit on the cage when on the inner. Theoretically yes; practically, no!

You’d get horrific chain rub as if the front mech was high enough to clear the outer ring the chain would sit on the cage when on the inner. Theoretically yes; practically, no!

Perhaps (yer very probably crap) – but then front shifters can do big jumps see some triples with 22/34/50 so you could use a triple derailluer to make use of the big cage.. n fact lots of older tourers have big jump doubles using old TA chainsets (TA Cyclotourist – lovely chainsets)

50/28

still your right probably not ideal.

but then front shifters can do big jumps see some triples with 22/34/50 so you could use a triple derailluer to make use of the big cage

Those ratios sound just as bad! That would be better, but as the plane the mech moves in is diagonal you need the horizontal movement (ie across 3 rings) to get the vertical clearance. But yes, there’s nothing practical stopping you, and I’m sure with a bit of bodging you could make it work. Ish.

yep as i said not ideal, but as above in touring land big double jumps are quiet common as in the picture above which is a 50/28

take a trip out with some wool clad CTCers 😉

it works for them as they are not constantly shifting back and forth (plus they know no better ;-))