Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Derailleur rubbing on the chain ring when I pedal hard

Search
Notices
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.

Derailleur rubbing on the chain ring when I pedal hard

Thread Tools
 
Search this Thread
 
Old 09-08-04, 03:47 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Jan 2004
Location: NorCal
Posts: 24

Bikes: My 2000 Rockhopper Pro has a Surley Rigid front fork and 26 X 1.5 Nimbus Armadillos. Also have a 2003 Specialized 24" TR-X for MotoXing with my kids. And a 2002 XR400 which I don't ride nearly enough

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Derailleur rubbing on the chain ring when I pedal hard

When pedaling lightly no problem. But when I start to put pressure by either going up hill or a sprint they rub. I was thinking it may be the cranks flexing under the stress.
The bike is a 2000 RockHopper pro. Alum frame and cranks
TR-X is offline  
Old 09-08-04, 03:51 PM
  #2  
Chi
Rides with Cows
 
Chi's Avatar
 
Join Date: Apr 2003
Location: Fixing a flat
Posts: 1,232

Bikes: Trek 7000

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Yes..
__________________
Chi is offline  
Old 09-08-04, 08:13 PM
  #3  
Junior Member
Thread Starter
 
Join Date: Jan 2004
Location: NorCal
Posts: 24

Bikes: My 2000 Rockhopper Pro has a Surley Rigid front fork and 26 X 1.5 Nimbus Armadillos. Also have a 2003 Specialized 24" TR-X for MotoXing with my kids. And a 2002 XR400 which I don't ride nearly enough

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
How would I go about looking for a new set of cranks? What should I look for and what questions should I ask?
TR-X is offline  
Old 09-08-04, 09:24 PM
  #4  
Banned.
 
Join Date: Feb 2003
Location: Fort Wayne, Indiana
Posts: 4,761

Bikes: 84 Trek 660 Suntour Superbe; 87 Giant Rincon Shimano XT; 07 Mercian Vincitore Campy Veloce

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
You didn't say what crank you have now! Problem is that any good step up crank for a MTB is expensive like the Shimano XTR at $450; you could try the Shimano XT unit and see if that works. Another problem is that if it's frame flex and you spend money on a new stiffer crank-your still going to have the problem. You should take the bike into your LBS and have it checked to make sure frame flex is not the issue.

But I don't know that much about MTB's so I'm just guessing.
froze is offline  
Old 09-08-04, 10:18 PM
  #5  
Member
 
Join Date: Aug 2004
Location: Southern California
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Did you try adjusting the derailleur... or is it an obscene amount of rubbing?
EyeBike2 is offline  
Old 09-08-04, 10:46 PM
  #6  
Chi
Rides with Cows
 
Chi's Avatar
 
Join Date: Apr 2003
Location: Fixing a flat
Posts: 1,232

Bikes: Trek 7000

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Actually I think it's the bottom bracket that's flexing, not the cranks ... or maybe a combination thereof.

I found the new Shimano XT M760 cranks/bb combo set to be extremely stiff ... if there's any flex at all, it's the frame (it's an old Trek 7000 mtb frame). I also weigh about 135 lbs so I'm not that hard on equipment.

Some flex is normal. If it's really bugging you, I'd go for the new set.

I wouldn't use the XTR cranks if you have concerns about longetivity ... the chainrings are all aluminum (for weight savings), so they wear faster.
__________________
Chi is offline  
Old 09-09-04, 12:09 AM
  #7  
Junior Member
 
Join Date: Sep 2004
Posts: 9
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It's your chain length or missaligned deralier. Has nothing to do with flex.
worldf is offline  

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.