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

Pedals rotate when they shouldn't

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.

Pedals rotate when they shouldn't

Old 07-19-10, 03:12 AM
  #1  
mossi
Senior Member
Thread Starter
 
Join Date: Aug 2003
Posts: 171

Bikes: Cannodale Six/13 2007

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Pedals rotate when they shouldn't

Recently, I noticed that my pedals rotate even when they shouldn't. For example: when I walk with my bike to the car, pedals rotate. True, they rotate much slower than the rear wheel. Still they rotate! Today I checked while descending, and it did happened (by moving my legs from the cleats). I do not feel this while riding (legs in the cleats), probably because the pressure is relatively low.

I believe it shouldn't be like that. Is this such a problem that I should not ride my bike before it is fixed (I simply don't have the time to step by a LBS this week)? I think the time come to replace the chain, can this be the cause for this phenomenon?
Other ideas?

THanks in advanced.
mossi is offline  
Old 07-19-10, 03:16 AM
  #2  
dahut
Ridin' South Cackalacky
 
dahut's Avatar
 
Join Date: May 2010
Posts: 1,918
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
WHat kind of bike?
dahut is offline  
Old 07-19-10, 03:18 AM
  #3  
mossi
Senior Member
Thread Starter
 
Join Date: Aug 2003
Posts: 171

Bikes: Cannodale Six/13 2007

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Cannondale, with DA/10 and Mavic Ksyrium SL.
Can it this is a hub issue?
mossi is offline  
Old 07-19-10, 03:32 AM
  #4  
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 8,180

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 497 Post(s)
Liked 53 Times in 46 Posts
Hopefully, it just means your drivetrain has such low friction that the minimal drag from a normally operating freewheel is enough to turn it.

If you pull your rear wheel and the freewheel spins fine, it's a good sign.
Kimmo is online now  
Old 07-19-10, 07:41 AM
  #5  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 35,968

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 122 Post(s)
Tagged: 1 Thread(s)
Quoted: 4346 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Basically it means that the freewheel drag in the rear wheel is greater than the combined drag of the BB and chain running through the RD.

It could be a good thing as Kimmo suggests, or it could be that the freehub is a bit stickier than it needs to be. If it's been a long time since any service has been done, or if it's a new development, I suspect the latter, since friction tends to increase, not decrease.

It isn't a serious problem, and if the wheel spins freely with the bike off the ground you can ignore it, otherwise you might want to clean and lube the freehub.

BTW- before you take anything apart, look behind the cassette. Often little bits of string or other road crud get caught and wound around the hub behind the cassette creating friction between the two parts. Cleaning this out usually solves the problem.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 07-19-10, 08:44 AM
  #6  
dahut
Ridin' South Cackalacky
 
dahut's Avatar
 
Join Date: May 2010
Posts: 1,918
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
See there...
dahut is offline  
Old 07-19-10, 09:23 AM
  #7  
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 41,396

Bikes: 8

Mentioned: 188 Post(s)
Tagged: 0 Thread(s)
Quoted: 6874 Post(s)
Liked 229 Times in 187 Posts
you could thoroughly flush and re lubricate the freehub with very light machine oil,
but then you have to keep it up more often .. frequent re lube intervals.

Add a heavy pedal?
fietsbob is offline  
Old 07-19-10, 10:18 AM
  #8  
mossi
Senior Member
Thread Starter
 
Join Date: Aug 2003
Posts: 171

Bikes: Cannodale Six/13 2007

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It appears this is a known problem with Mavic wheels. Got advised not to ride until being fixed as it can result (if friction gets higher) in overload on the chain and harm the diversion components.
mossi is offline  
Old 07-19-10, 08:55 PM
  #9  
onetwentyeight 
blah
 
onetwentyeight's Avatar
 
Join Date: Oct 2005
Location: Oakland, CA
Posts: 5,573
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
This just is a sign of a dirty freehub body. Pull the freehub and clean and relube with heavy mineral oil. In the base of the Mavic hub there is also a rubber seal that has two sections, one thick and one thin. You can trim off the thin part to remove some of this pedal assist as well, it drags a little.
onetwentyeight is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
boshk
Road Cycling
10
06-20-17 09:48 PM
FreddyBoy
Training & Nutrition
3
04-10-09 04:42 AM
E500 C.E.
Triathlon
1
10-25-04 08:16 AM

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


Thread Tools
Search this Thread

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

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.