Compact Rings Sizes

Bluestoesonnose

Asked this on the wrong forum, earlier in the week, but again in the right one.

I'm thinking of going for a compact chainset, but I'd like a bigger outer ring than the 50 it comes with, what would be the biggest outer ring I could go for with a 34 inner?

The reason I'm asking is I live on Dartmoor and whilst I enjoy the speed I get from the 52 - 11 I currently have and can spin this up to 130 rpm. However the 39 inner is making life a little hard on the steep hills (I'm not getting any younger or lighter, despite my best efforts). I've changed the cassettee for an 11 - 28 but I'd like something a little lower hence the thought of a compact with a smaller inner.

Cheers
Blues

Monty Dog

You need to stick with a 16 tooth difference as that's the capacity of most front mechs - if you want a 52 outer, then you'll need to fit a 36 inner.

FatTed

52X11 @ 130 is 48.7 mph good going!

Spikeoz

You'd probably have to bastardise a system, use a triple front mech, the new Dura-ace crankset which allows for larger big ring than a standard compact, (hurray for the move away from diffrent BCD's), that will allow you to have a 54 , 34 setup in theroy, the biggest pain will be the rear derailuer you'd probably need to go to a mountain bike style one with a long cage to handle the 54-28 to 34-11 take up which is 37 teeth, you need to find a way to gain/loose 37 links in the system, i belive you can get a 52-36 road setup that might be okay

chrisvanderkaap

companies like TA and stronglight make up until 54t for 110 bcd (compact) cranks so no worries there.
Indeed the only problem is with the range of the front derailleur and the risk of dropping a chain.

the ideal middle solution is whats called a mid-compact. 52-36 As now is also more commonly used by specialized.
This change can be made with said chainrings and no alterations to crank or front derailleur (except for height).

good luck!

dennisn

FatTed wrote:

52X11 @ 130 is 48.7 mph good going!

I was going to say that. Kind of weird but there seem to be quite a few people out there claiming to push a 52 or 53 - 11 with great regularity.
FWIW I think an 11 tooth cog is useless. All it will do is sit out there and mock you.

k-dog

^ definitely. I'd much rather have a decent useable range of gears - 50/34 and 12-25 works for me.

It's not often I want anything more at either end - and the loss of a couple of mph on a rare long/steep descent is worth it IMO.

dennisn

Monty Dog wrote:

You need to stick with a 16 tooth difference as that's the capacity of most front mechs - if you want a 52 outer, then you'll need to fit a 36 inner.

I was using a 50 - 33 front setup(DA 9 spd.) whenever I went out to do the Bike Tour of Colorado. That's 17 teeth and never had a problem but I doubt I could have gone any more. I believe that gear capacities(front and rear), as stated by manufacturers, are conservative for legal reasons. A tooth or two more maybe but the risk of trashing your front and or rear D isn't worth the risk.

I guess I'm saying disregard what I do and do what the specs call for. :oops:

andrew_s

dennisn wrote:

FatTed wrote:

52X11 @ 130 is 48.7 mph good going!

I was going to say that. Kind of weird but there seem to be quite a few people out there claiming to push a 52 or 53 - 11 with great regularity.
FWIW I think an 11 tooth cog is useless. All it will do is sit out there and mock you.

Agreed. I'm waiting for someone to sell me a 13 or 14 up cassette so I don't have these wasted gears.

If 130rpm on 53x11 isn't fast enough, learn to pedal faster. When you get up to 160 or 180 rpm, then you are justified in getting a TA 60T chainring for your compact chainset.