Changing chain set

koor

hi All

İf i was to change from 170mm - 53.39t to a compact 170mm - 50.34t, what else would i need to change ?

Regards

dennisn

Possibly your chain length.
Front "D" will have to be readjusted(lowered).
If you're buying the same brand(i.e. Shimano out board bearing to Shimano out board bearing) then the bottom bracket should be OK. Key word "should".
Other than that you should be good to go.

smidsy

If your front DR is band on it is simple, less so if it is braze on.

arran77

If it's braze on you may need something like this to get the derailleur at the correct height for the compact chainset....

koor

arran77,dennisn & smidsy


Thanks for the replies and information. i thought i might need to change the rear mech.

arran77

Shouldn't need to do that I don't think, gears will probably need adjusting generally which is relatively straight forward, have a read of this...

http://www.bikeradar.com/gear/article/workshop-shifting-problems-20350/

smidsy

arran77 wrote:

If it's braze on you may need something like this to get the derailleur at the correct height for the compact chainset....

I actually meant if the frame he has is braze on. If this is the case the frame has the fixing point already, but it will be in the wrong place.

arran77

smidsy wrote:

arran77 wrote:

If it's braze on you may need something like this to get the derailleur at the correct height for the compact chainset....

I actually meant if the frame he has is braze on. If this is the case the frame has the fixing point already, but it will be in the wrong place.

Is that not the idea of the slot so that you can adjust the mech up or down?

I was only thinking if the fixing point already there was in the wrong place like you say there might be a need for this to get it to the correct height.

koor

hi

it is braze on, thanks arran77 for the info i didn't even know that band on (braze thingy ) existed

nochekmate

koor wrote:

hi All

İf i was to change from 170mm - 53.39t to a compact 170mm - 50.34t, what else would i need to change ?

Regards

Your cadence?

declan1

I did that exact change recently and I just moved the front mech down a bit. I put a new chain on at the same time so I don't know if it needed a different length but it may just need a couple of links taking out.

Grill

Arran77 is correct. The only cases I've ever com across where the stock braze-on mounting pointing I lacking in adjustability is with Osymmetrics and QXL rings and even then it's that the front mech can't be moved high enough.

Wirral_paul

There's often two attachment points for the bolt that goes through the braze on point on the mech itself to allow for additional adjustment to lower the mech for a compact. SRAM do at least on the Red derailleur anyway