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


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 03-09-09, 05:31 PM   #1
tmh657
Senior Member
Thread Starter
 
tmh657's Avatar
 
Join Date: Aug 2008
Location: SoCal
Bikes: A few BSO's.
Posts: 2,470
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
New crank arm fit_BB compatability

I have a Suntour BB with Suntour Sprint cranks.
Just got a Shimano 600 Crank, (I wanted longer arms).

They are both square taper but the Suntour cranks go about 7/8 of the way on the spindle and then get tightened.

The Shimano crank goes almost all the way onto the spindle to the BB shell.

I am guessing the BB is not the correct taper for the Shimano crank since if tightened it would be against the BB shell.

Any ideas?
Thanks.
Attached Images
File Type: jpg Picture 17.jpg (47.6 KB, 9 views)
tmh657 is offline   Reply With Quote
Old 03-09-09, 06:34 PM   #2
Panthers007
Great State of Varmint
 
Panthers007's Avatar
 
Join Date: Sep 2008
Location: Dante's Third Ring
Bikes:
Posts: 7,479
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Get another bottom-bracket for the Shimano. Shimano and Suntour rarely get along.
Panthers007 is offline   Reply With Quote
Old 03-09-09, 07:32 PM   #3
DOS
Senior Member
 
DOS's Avatar
 
Join Date: Feb 2008
Location: Arlington, VA USA
Bikes:
Posts: 1,486
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Suntour on some BBs used a slightly different taper than JIS or ISO so fit between a Suntour and either JIS or ISO components will be slightly off. I don't know about your set up, but I have Suntour cranks on a Campy BB and they work fine. Sounds like your cranks will stay on snug but your chainline will be off. FWIW, My Suntour Superbe cranks are fantastic and I got em for next to nothing on EBAY so in addition to considering Panther007 suggestion of replacing your BB, you might look into new cranks to match your BB (although replacing the BB will be the cheaper option).
DOS is offline   Reply With Quote
Old 03-09-09, 07:54 PM   #4
Grand Bois
Senior Member
 
Grand Bois's Avatar
 
Join Date: Mar 2005
Location: Pinole, CA, USA
Bikes:
Posts: 16,681
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 85 Post(s)
They all have the same 2 degree taper. JIS spindles are "stubbier".
Grand Bois is offline   Reply With Quote
Old 03-09-09, 08:19 PM   #5
tmh657
Senior Member
Thread Starter
 
tmh657's Avatar
 
Join Date: Aug 2008
Location: SoCal
Bikes: A few BSO's.
Posts: 2,470
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Quote:
Originally Posted by DOS View Post
FWIW, My Suntour Superbe cranks are fantastic and I got em for next to nothing on EBAY so in addition to considering Panther007 suggestion of replacing your BB, you might look into new cranks to match your BB (although replacing the BB will be the cheaper option).
Just got the Shimano cranks today in the mail from ebay purchase for a good price so a $24 Shimano UN54 w/ 118mm length will be purchased tomorrow.
Kinda sucks since that's more than I paid for the crank.

Oh well, the Suntour BB and Sprint crank will go in a drawer for now. It's a 170mm. Not sure why they outfitted the bike with 170's in 1988.
Schwinn put 165mm cranks on smaller frames.
The cranks are great just too short for me.

Thanks for the help guys.
tmh657 is offline   Reply With Quote
Old 03-09-09, 08:44 PM   #6
DOS
Senior Member
 
DOS's Avatar
 
Join Date: Feb 2008
Location: Arlington, VA USA
Bikes:
Posts: 1,486
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Quote:
Originally Posted by Dirtdrop View Post
They all have the same 2 degree taper. JIS spindles are "stubbier".
When determining whether my campy BB would work with ST superbe cranks, I had read in several places that Superbe used a different taper; with one cite indicating 1.8 degree vice 2.0. I never botherd to do any measurement myself but nor did I have any reason to question the assertion.
DOS is offline   Reply With Quote
Reply


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 06:31 AM.