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

New: Take Part in the March Giveaway: Coming Soon


Cassette Sizes
#1
Hi guys,

I'm currently have a Shimano 105 derailleur, 11-25T 10 Speed. I want more help on hills, and will be switching to a 11-27 or 12-27 cassette. I'll buy a new chain also.

What is the difference between the 11-27 and 12-27? Will I have to change my derailleur since this will be a new size?
  Reply
#2
Difference is one tooth, or a bit less than 10%, but mainly the 11 tooth is next to useless, assuming you have a 48 tooth or larger chainring. Derailleur is not affected at all for the small cog, and depending on which model 105 you have it will handle at least 28 teeth on the large end.
  Reply
#3
The difference on paper would be a pinch faster top end assuming you can spin it. If your bike is a triple either one would be fine, if your bike is a double you may want to consider an 11t-28t. that would be my choice. this is a debatable subject for sure with many opinions. Nothing makes hills better than being in incredible shape, thats the tough part! Smile No, your derailleur should be fine
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
  Reply


Possibly Related Threads...
Thread
Author
Replies
Views
Last Post
 
3,767
01-02-2022, 04:53 AM
Last Post: Jesper
 
3,099
06-24-2020, 04:13 PM
Last Post: CharleyFarley
 
21,853
12-13-2019, 09:53 PM
Last Post: RJD
 
14,726
03-21-2016, 02:29 PM
Last Post: budstutor
 
7,513
10-28-2010, 03:31 AM
Last Post: cuzzo142
 
21,405
10-13-2010, 06:04 AM
Last Post: rogerthat
 
11,211
01-09-2010, 06:19 PM
Last Post: Bill
 
25,270
11-18-2009, 06:00 AM
Last Post: Joe_W
 
10,000
09-08-2008, 03:55 PM
Last Post: DaveM

Forum Jump:

[-]
10 Latest Posts
2010 Specialized Hardrock
Today 07:02 PM
Why do spokes break?
Today 02:34 PM
Vilano Warning
Today 02:13 PM
Scram Force Front Derailleur
Today 01:55 PM
Hello from Connecticut USA
Yesterday 02:57 AM
Bicycle Touring and Camping
Yesterday 02:48 AM
New hip fracture, looking for some words...
Yesterday 02:44 AM
Upgrading The Vilano Diverse 3.0 DriveTr...
03-16-2024 12:21 PM
Lectric One
03-15-2024 07:19 PM
PAS Level 4 and 5
03-15-2024 07:16 PM

[-]
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. meamoantonio
23 posts
no avatar 2. GirishH
19 posts
no avatar 3. ichitan
18 posts
no avatar 4. ReapThaWhirlwind
18 posts
no avatar 5. Painkiller
17 posts