Bicycle TutorBicycle Tutor

Show off your bike!

Related video tutorials:
Changing to a larger chainring
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?)

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
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:

Take a look at this as well:

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.

Possibly Related Threads...
Thread Author Replies Views Last Post
  Changing inner chainring and cassette for touring tarquin1234 4 8,539 06-03-2011, 03:32 AM
Last Post: nfmisso
  Changing 3 gear chainring to single gear flyguy_helo 6 15,208 01-15-2010, 10:06 PM
Last Post: theovzyl

Forum Jump:

ISSN 1918-3445 © Copyright 2007-2010 Bicycle Tutor / Privacy Policy / Created by Alex Ramon