Wobbly crank arm
 

  You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more

[Closed] Wobbly crank arm

7 Posts
4 Users
0 Reactions
57 Views
Posts: 0
Free Member
Topic starter
 

Hi. I have a drive side crank arm that is wobbling despite the crank bolt being nice and tight. It's a Middleburn RS7 on a new Superstar Isis BB. I'm wondering if there's a way of tightening uo the arm? Is there such a thing as an additional washer that you can fit to tighten up the fit? Ta...


 
Posted : 16/05/2020 4:36 pm
Posts: 3590
Free Member
 

Has it developed the wobble over time, or was the wobble there since the crank/BB was installed?.


 
Posted : 16/05/2020 5:07 pm
Posts: 25815
Full Member
Posts: 0
Free Member
Topic starter
 

It's become wobbly after just a couple of rides. I'll remove the arm fully, clean/grease and re-fit I think. I am using a crank bolt with an integrated washer but the washer looks worst for wear after just a few rides...


 
Posted : 16/05/2020 7:06 pm
Posts: 6235
Full Member
 

Unfortunately, when the splines in the aluminium arm are even a bit worn, it will always end up loosening after a ride or two, however hard you crank up the bolts.

I've got some RaceFace Aeffect cranks that have gone the same way 🙁


 
Posted : 16/05/2020 7:11 pm
Posts: 3590
Free Member
 

If they're new you should be able to tell visually which has damage that's causing the wobble, or something causing the bolt to not fully engage. ISIS bbs have a bad rep, not entirely deserved, but it shouldn't be bad from the outset.


 
Posted : 16/05/2020 7:48 pm
Posts: 0
Free Member
Topic starter
 

Removed the crank arm only to find a section of it has completely sheared off. No wonder it was wobbly. Looks like I now need to replace the cranks null


 
Posted : 17/05/2020 2:40 pm
Posts: 0
Free Member
Topic starter
 

Struggling to insert an image on this forum...


 
Posted : 17/05/2020 2:57 pm

6 DAYS LEFT
We are currently at 95% of our target!