Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take Part in the October Giveaway to Win the Qiolor TIGER Retro Electric Bike


Changing 53/39 chainrings to 50/34
#1
I'm looking to change a Shimano 105 53/39 crank/chainring to a 105 (or higher spec) 50/34 chainring. Can anyone please tell me what is involved with this? Do I just need to change the chainrings, or am I going to end up needing to change pretty much the whole drive train? Thanks.
  Reply
#2
A 50T would fit where the 53T is but the 34T won't fit instead of the 39T.
It's to do with the "PCD" (pitch circle diameter) of the chainset.
ie the mounting holes for the rings are on a different radius for the small ring.
You will need change the right crank or change the chainset as a whole.
The chances are your PCD is 130mm whereas you need 110mm for the 50/34 chainrings.

See:-
http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_1M30A/SI-1M30A-003-ENG_v1_m56577569830702207.pdf

The other thing you will have to check is if the front dérailleur is also compatible with the smaller ring?
Probably is but some aren't.
Ride hard or ride home alone!
  Reply


Possibly Related Threads...

Forum Jump:

[-]
10 Latest Posts
Schwinn trike NOISE
Today 05:20 PM
Schwinn meridian rear drive axle
Today 04:36 PM
What was your first bicycle?
Yesterday 04:11 PM
Great UK Cycle Camping Map, For E-Bikes,...
Yesterday 05:38 AM
Charging at campground
Yesterday 05:33 AM
Failure to stop at stop sign means $500 ...
Yesterday 05:27 AM
Bicycle enthusiast located in California
Yesterday 04:15 AM
Moving in Style: Beyond Regular Transpor...
Yesterday 01:29 AM
Do you plan or random ride your MTB ride...
11-02-2024 11:43 AM
Cycling is Anti-Aging, But There's a Cat...
11-02-2024 11:36 AM

[-]
Join BikeRide on Strava
Feel free to join if you are on Strava: www.strava.com/clubs/bikeridecom

[-]
Top 5 Posters This Month
no avatar 1. Jesper
18 posts
no avatar 2. enkei
18 posts
no avatar 3. GirishH
13 posts
no avatar 4. Flowrider
12 posts
no avatar 5. Talha
10 posts