Crank keeps coming loose
#1
Senior Member
Thread Starter
Join Date: Oct 2010
Location: Gulf Breeze, FL
Posts: 4,128
Bikes: Rossetti Vertigo
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 229 Post(s)
Liked 119 Times
in
70 Posts
Crank keeps coming loose
Been having a recurring problem lately. The bolts on the left crank arm keep coming lose. Should I use locktight? Suggestions?
#2
Senior Member
Join Date: Jul 2007
Posts: 1,039
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 75 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Have you tightened it with a torque wrench? The non-drive side loosening up on SRAM cranksets seems to be pretty common if it's not tightened to the maximum of the range specified by SRAM. I had it happen on one of my Rival cranksets.
#4
Voice of the Industry
Join Date: May 2007
Posts: 12,572
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1188 Post(s)
Likes: 0
Liked 8 Times
in
8 Posts
Likely undertorqued as mentioned. If you don't have a lot of experience wrenching...even if you do...I generally use a torque wrench on cranks...invest in a good 3/8" drive torque wrench. Doesn't have to be high end wrench like Snapon...Craftsman will suffice. Also good to own a set of socket allens....hex allen bits attached to socket which plug into a torque wrench. Sometimes torque target isn't achievable with L shaped allen due to lack of leverage...or owner doesn't know the torque target. Your post is unclear...you may mean the single center crank bolt...depends on the crank...but if you are refering to left crank arm dual pinch bolts aka Shimano...torque in thirds...set torque wrench 1/3, 2/3 and full torque spec and alternate bolts for uniform clamping. Torque specs are generally found on the web...most crank makers have service manual PDF's on line. I always use a dap of grease on the spline to prevent bonding. Inspite of lubrication, this actually helps clamping strength...grease is captured in micro-voids between male and female splines improving clamp strength.
Last edited by Campag4life; 02-09-13 at 07:22 AM.
#5
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,844
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 931 Times
in
616 Posts
Look closely for cracks or other problems. I had an old square taper that came loose. Realized the left arm had a crack that spread open as it was tightened.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
#6
ka maté ka maté ka ora
Join Date: Oct 2008
Location: wessex
Posts: 4,423
Bikes: breezer venturi - red novo bosberg - red, pedal force cg1 - red, neuvation f-100 - da, devinci phantom - xt, miele piste - miche/campy, bianchi reparto corse sbx, concorde squadra tsx - da, miele team issue sl - ultegra
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
Likely undertorqued as mentioned. If you don't have a lot of experience wrenching...even if you do...I generally use a torque wrench on cranks...invest in a good 3/8" drive torque wrench. Doesn't have to be high end wrench like Snapon...Craftsman will suffice. Also good to own a set of socket allens....hex allens bits attached to socket which plug into a torque wrench. Sometimes torque target isn't achievable with L shaped allen. When it comes to dual pinch bolts...torque in thirds...set torque wrench 1/3, 2/3 and full torque spec and alternate bolts for uniform clamping. Torque specs are generally found on the web...most crank makers have service manual PDF's on line. I always use a dap of grease on the spline to prevent bonding. Inspite of lubrication, this actually helps clamping...grease is captured in micro-voids between male and female splines.
#7
Voice of the Industry
Join Date: May 2007
Posts: 12,572
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1188 Post(s)
Likes: 0
Liked 8 Times
in
8 Posts
I will tell you what I believe to be most problematic which it comes to adding grease or anti seize to cranks. Older square taper Campy cranks were 'extremely' sensitive to adding grease to the square taper. This would not only affect the center bolt torque spec, but how far the spider or non drive side arm would draw onto the spindle. To me, this was a fundamental weakness of square taper. Another volatile debate pertained to whether to add grease or not to the square taper...a matter of philosophy. Many who didn't, ended up with creaky cranks.
Last edited by Campag4life; 02-09-13 at 07:52 AM.
#9
CAT4
Join Date: Jun 2007
Location: Omaha, Nebraska
Posts: 1,681
Bikes: 2009 Cervélo S1, 2009 Felt F75, 2010 Cannondale Synapse Carbon 5, 2011 Cannondale CAADx, 2011 Specialized Transition Elite
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Use loctite blue. I recently had an FSA crank come apart on me during a ride. One of the crank arms just dropped...