Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  

Go Back   > >

Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

User Tag List

Thread Tools Search this Thread
Old 04-02-09, 06:20 AM   #1
Senior Member
Thread Starter
Join Date: Jul 2007
Posts: 74
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
R20/SXRF 8 speed Gearing Question

Hello everyone,
I'm considering upgrading the BB and cranks on my R20 and would like to know how reasonably small a chain ring I can use. I have bad knees, like to spin uphill (actually all the time) and find a bit lower gear would benefit me greatly. I have the 305% XRF8 hub and never use 8th gear and only occasionally 7th. Will a 42 or 44 tooth ring be enough of a change or will it throw off the entire ratio through the rest of the gears? I purchased a UN72 73 X 113 BB and will probably go with the Phil rings when I have the time and cash to do the rest. Also, any crank recommendations? Thanks for any advice. I'm looking forward to getting back on the bike after a long winter of eating.
veloceleste is offline   Reply With Quote
Old 04-03-09, 09:53 AM   #2
Join Date: Jan 2007
Location: Portland, OR
Bikes: Univega Gran Turismo, Cannondale Synapse, Bianchi Aquiletta Folder
Posts: 276
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have a 40-tooth sprocket and a 25 tooth cog (standard) on my 406-wheeled R20 with an S/A 8-speed hub. It has a 29.9 inch low and a 91 inch high gear, which allows me to spin up pretty steep stuff. Sheldon, rest his soul, made a gear calculator so you can compare things:
I use 165 mm cranks, but that's just what the chainring came with. I've heard that shorter cranks spin better and longer cranks are better for people with longer femurs, but I really can't tell the difference much. Certainly, a shorter crank, 165mm or less, is better for avoiding petal strike, which may be a problem on a small-wheeled bike. Me, I don't go fast enough around corners to make it a problem
Squeazel is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 03:02 PM.