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

New: Take Part in the February Giveaway for a Chance to Win 2x METRO Hybrid Bikes


Changing to a larger chainring
#1
I have a Trek Portland that I am using for touring and need to get a better gear ratio for climbing large hills while fully loaded. The bike currently has a Shimano CS-5700 11-25. I would like to put on a Shimano Deore XT mountain bike cassette CS-M771 11-36. Is there any thing that I should be aware of before making this change? (longer chain?, different rear derailer?)
Brent

For instance, the bicycle is the most efficient machine ever created: Converting calories into gas, a bicycle gets the equivalent of three thousand miles per gallon. ~Bill Strickland, The Quotable Cyclist

http://cyclingat50.blogspot.com/
  Reply
#2
They're both 10 speed so the index spacing should be OK, but you will likely need a longer chain and a long cage rear derailleur.

You could also consider fitting smaller chainrings on the front, or perhaps just a smaller inner chainring. However, one very small chainring in combination with one large might also require a long cage derailleur to take up the excessive slack.

Try a gear calculator to see what combinations result in similar gearing: http://cycleseven.org/bicycle-gear-inch-calculator

Take a look at this as well: http://www.parktool.com/blog/repair-help/chain-length-sizing
  Reply
#3
Brent;

I concur with Xerxes; take a look at changing the smallest chainring instead. This is a much cheaper alternative, and lets you keep the nice close ratio gears you have. On the practical side; if you avoid using the smallest chainring with the smaller rear cogs - not a good idea anyway due to interference of the chain with the larger chainrings - you do not have to worry about changing the chain.

There is an extremely limited selection of rear derailleurs that will work with a 36T rear cog, going only to 34T will provide many more options. It doubtful that your current rear derailleur will go beyond 28T.
Nigel
  Reply


Possibly Related Threads...
Thread
Author
Replies
Views
Last Post

Forum Jump:

[-]
10 Latest Posts
Why do spokes break?
Today 12:10 PM
Staying Active as the Wet, Cold & Darkne...
Today 11:48 AM
How to keep your bicycle safe?
Today 04:50 AM
Slingshot road bike
Today 04:43 AM
Ground breaking design or gimmick ?
Today 04:30 AM
WTB Raddler TCS 40c, small cut - repaira...
Yesterday 09:01 AM
Customize your profile (photo, signature...
02-19-2024 06:24 AM
Official Shimano 105 Crankset Raw Weight...
02-19-2024 01:12 AM
1990 Specialized Rockhopper How to Fluff...
02-18-2024 11:30 AM
E Bike Rental Bled
02-17-2024 02:16 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. GirishH
26 posts
no avatar 2. enkei
19 posts
no avatar 3. ReapThaWhirlwind
15 posts
no avatar 4. Jesper
14 posts
no avatar 5. Painkiller
12 posts