Wobbling crank
11-21-20, 11:27 AM
#1
Junior Member
Thread Starter
Join Date: Nov 2020
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked 0 Times
in
0 Posts
Wobbling crank
Hello everyone 
I bought this cheap bike with a wobbly crank/shaft?
I would like to fix it myself however I am not sure how to determine the exact parts I need to buy in order to do so. I watched some YT videos but I am still a little bit confused cause there's many different types of shafts and I am not even sure what part need to be changed.
I could just go to bike shop (I actually went, and the diagnosis was that the shaft needs to be changed £50). But I like doing stuff myself anyway and as I have some spare time I though it would be a nice thing to know how to do.
I am attaching close-up photos. I also have video of it wobbling but I cant post it here ;/
If any one would be so kind to let me know what tools and parts I should buy in order to do it I would be very grateful!
Stay safe,
I bought this cheap bike with a wobbly crank/shaft?
I would like to fix it myself however I am not sure how to determine the exact parts I need to buy in order to do so. I watched some YT videos but I am still a little bit confused cause there's many different types of shafts and I am not even sure what part need to be changed.
I could just go to bike shop (I actually went, and the diagnosis was that the shaft needs to be changed £50). But I like doing stuff myself anyway and as I have some spare time I though it would be a nice thing to know how to do.
I am attaching close-up photos. I also have video of it wobbling but I cant post it here ;/
If any one would be so kind to let me know what tools and parts I should buy in order to do it I would be very grateful!
Stay safe,
11-21-20, 11:33 AM
#2
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,096 Times
in
742 Posts
What make and model of bike? What make and model of crank?
Park Tool's web site has a large number of tutorials on all aspects of bike repair so see if you can find the type of crank you have there.
Park Tool's web site has a large number of tutorials on all aspects of bike repair so see if you can find the type of crank you have there.
Likes For HillRider:
11-21-20, 11:34 AM
#3
Senior Member
There are no photos attached.
__________________
Two wrongs don't make a right but three lefts do! Unknown
Two wrongs don't make a right but three lefts do! Unknown
11-21-20, 11:40 AM
#4
Senior Member
Join Date: Mar 2007
Location: SF Bay Area, East bay
Posts: 7,658
Bikes: Miyata 618 GT, Marinoni, Kestral 200 2002 Trek 5200, KHS Flite, Koga Miyata, Schwinn Spitfire 5, Mondia Special, Univega Alpina, Miyata team Ti, Santa Cruz Highball
Mentioned: 53 Post(s)
Tagged: 0 Thread(s)
Quoted: 1609 Post(s)
Liked 2,590 Times
in
1,224 Posts
assist
11-21-20, 11:46 AM
#5
Senior Member
Join Date: Mar 2008
Posts: 8,688
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 1074 Post(s)
Liked 295 Times
in
222 Posts
That’s a square taper cup&cone BB.
I’d try to tap the lockring loose, screw in the NDS cup a little and tighten the lockring again.
Anything beyond that, odds are you’ll be spending a fair amount of the quoted price on tools before you’d get the job done.
I’d try to tap the lockring loose, screw in the NDS cup a little and tighten the lockring again.
Anything beyond that, odds are you’ll be spending a fair amount of the quoted price on tools before you’d get the job done.
Likes For dabac:
11-21-20, 07:18 PM
#6
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,784
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3588 Post(s)
Liked 3,400 Times
in
1,934 Posts
Is it one arm wobbling on the spindle, or the whole assembly (both arms and spindle) that wobble together as a unit?
If the former, the arm has worked loose on the spindle. Unfortunately, that often means that the arm has been damaged and needs to be replaced. You can snug up the retaining nut or bolt and see if it stays tight. If you're lucky, it will and you're home free. If it keeps loosening up, you'll need to replace the arm.
If the latter, the bearings are out of adjustment. @dabac's suggestion above can tighten it up again, but it's also possible that the internal parts have become damaged. If, after tightening the adjustment per dabac's suggestion it makes unpleasant noises, binds, or otherwise doesn't behave as expected, you'll need to open it up and inspect the parts for damage.
If the former, the arm has worked loose on the spindle. Unfortunately, that often means that the arm has been damaged and needs to be replaced. You can snug up the retaining nut or bolt and see if it stays tight. If you're lucky, it will and you're home free. If it keeps loosening up, you'll need to replace the arm.
If the latter, the bearings are out of adjustment. @dabac's suggestion above can tighten it up again, but it's also possible that the internal parts have become damaged. If, after tightening the adjustment per dabac's suggestion it makes unpleasant noises, binds, or otherwise doesn't behave as expected, you'll need to open it up and inspect the parts for damage.
Likes For JohnDThompson:
11-22-20, 10:16 AM
#7
Senior Member
Join Date: Mar 2007
Location: SF Bay Area, East bay
Posts: 7,658
Bikes: Miyata 618 GT, Marinoni, Kestral 200 2002 Trek 5200, KHS Flite, Koga Miyata, Schwinn Spitfire 5, Mondia Special, Univega Alpina, Miyata team Ti, Santa Cruz Highball
Mentioned: 53 Post(s)
Tagged: 0 Thread(s)
Quoted: 1609 Post(s)
Liked 2,590 Times
in
1,224 Posts
A friend got one of these to get some exercise. At 260, he bent the spindle pretty quick. Some bikes are cheap for a reason.
Likes For curbtender:
11-22-20, 01:08 PM
#8
Senior Member
Join Date: Mar 2008
Posts: 8,688
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 1074 Post(s)
Liked 295 Times
in
222 Posts
Is it one arm wobbling on the spindle, or the whole assembly (both arms and spindle) that wobble together as a unit?
If the former, the arm has worked loose on the spindle. Unfortunately, that often means that the arm has been damaged and needs to be replaced. You can snug up the retaining nut or bolt and see if it stays tight. If you're lucky, it will and you're home free. If it keeps loosening up, you'll need to replace the arm.
If the former, the arm has worked loose on the spindle. Unfortunately, that often means that the arm has been damaged and needs to be replaced. You can snug up the retaining nut or bolt and see if it stays tight. If you're lucky, it will and you're home free. If it keeps loosening up, you'll need to replace the arm.
Likes For dabac:
11-25-20, 05:09 AM
#9
Junior Member
Thread Starter
Join Date: Nov 2020
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked 0 Times
in
0 Posts
I think it was the entire unit that was wobbling. As suggested I tightened it up. I only had a wrench and a flathead screwdriver but it worked just fine! Must've just loosen over time.
I've saved £50 for now. We'll see for how long it will stay like that If it'll go back to being loose I will open it up and see what's the root problem!
Thanks!
I've saved £50 for now. We'll see for how long it will stay like that
If it'll go back to being loose I will open it up and see what's the root problem!Thanks!
