1x10 chain ring size

andylit

hi,

i am currently waiting for my new bike to turn up and i am planning on changing it to 1x10 (my current bike is 1x9)

however, since ordering the bike i have realised it has a 120 BCD on the cranks which limits my chain ring size to a minimum of 36 teeth. is this going to be too big? cassette is 11-36

thanks

Chunkers1980

If the wheel sizes are the same then try 32/32 or whatever you have to make 1:1 and see?

andylit

thanks, will need to have a look at the cassette size on my current bike.

any more views from others would be appreciated too

warpcow

Only you can know if it'll be too big. It'd be on the upper limit of what I'd push; 34t and 11-36 cassette works well allround for me.

If the cranks are nicer SRAM (guessing since they're 120mm BCD) you could use a direct-mount ring.

njee20

I run a 36t single ring (with 11-36 block) wouldn't want to go smaller. Not for everyone though.

andylit

the cranks are only X5 so i think the option of direct mount is out. dont want to upgrade the cranks yet

andylit

also, having just had a look at the cranks online i think there may be clearance issues with chain guides. anyone know is this would be true

lostboysaint

njee20 wrote:

I run a 36t single ring (with 11-36 block) wouldn't want to go smaller. Not for everyone though.

Not as fit as Njee so have a 34 on a 11-34 cassette!!

andylit

in theory though, if you are running a 34 with 11-34 and Njee is running a 36 with 11-36, in the lowest gear the ratio is the same at 1:1 i know the other ratios will be different but when grinding up a hill the lowest gear is the one that matters

Maro

I currently use a 38 with (9speed) 11-32. It's hard work on steep or very long climbs but certainly do-able.

njee20

That's pretty tall, I know I couldn't do that!

andylit

that is tall. think i may give the 36t a try. but i am a little concerned about the chain guide clearance on the 120BCD cranks

njee20

Yes it could be an issue - most chain guides will be optimised to sit in the middle ring position of a triple, whereas yours will be in the outer position of a double and thus a couple of mm further out. I've got an E.13 XCX guide to fit to mine, but may well have the same issues (XTR M985 double), in which case I've got a home made guide using a Superstar cage and a DMR seat tube mount.

andylit

Thing i may leave it as 2x10 and maybe put a 2x chain device on it. and possibly reduce the 42 outer ring to a 39. would i need to do anything to the front derailleur if i reduce the size of the outer ring?