Pedal crank

DavidN

Member
Hi, my left pedal crank keeps coming loose, started last week with a sort of creaking noise coming from crank, then noticed it getting a bit jerky and when i investigated discovered retaining bolt was loose so tightened it back up but next day it started again so i applied thread lock and tightened as hard as i could but is still coming loose within a mile of setting off ! I've only done around 400 miles and never been offroad so not sure how this has happened. Anyone any ideas/solutions ?
Thanks
 

RJC

Active Member
Hi, my left pedal crank keeps coming loose, started last week with a sort of creaking noise coming from crank, then noticed it getting a bit jerky and when i investigated discovered retaining bolt was loose so tightened it back up but next day it started again so i applied thread lock and tightened as hard as i could but is still coming loose within a mile of setting off ! I've only done around 400 miles and never been offroad so not sure how this has happened. Anyone any ideas/solutions ?
Thanks
It's probably worn the crank and also the bottom bracket spindle. The spindle has a taper on it so as you tighten the crank arm bolt the arm is pushed on nice and tight. When the arm became loose it may have worn the square hole in it so the arm no longer pushes tight onto the spindle. If the spindle looks ok I would try replacing the arm and bolt. The bottom bracket comes complete with spindle and bearings. Relatively easy to fit but you will need a couple of special tools which don't cost much. If still in warranty Leon Cycles should sort it.
 

DavidN

Member
It's probably worn the crank and also the bottom bracket spindle. The spindle has a taper on it so as you tighten the crank arm bolt the arm is pushed on nice and tight. When the arm became loose it may have worn the square hole in it so the arm no longer pushes tight onto the spindle. If the spindle looks ok I would try replacing the arm and bolt. The bottom bracket comes complete with spindle and bearings. Relatively easy to fit but you will need a couple of special tools which don't cost much. If still in warranty Leon Cycles should sort it.
Yes just noticed the other thread about loose crank, im going to change the bottom bracket, Halfords have one at £10 which has a lot of good reviews, £20 for the crank puller and bracket removal tool. I've emailed Leoncycles but dont know how they will feel about me doing it myself !
 

RJC

Active Member
Yes just noticed the other thread about loose crank, im going to change the bottom bracket, Halfords have one at £10 which has a lot of good reviews, £20 for the crank puller and bracket removal tool. I've emailed Leoncycles but dont know how they will feel about me doing it myself !
This is the one I used. Shimano BB-UN26 Bottom Bracket - Black, 68-122 mm on Amazon. It was a better make than the original NECO one fitted. I think it was around £15/£20, Leon cycles were ok to pay for that one plus the labor under warranty. If you send them an invoice from yourself for the labor quoted by Halfords plus the part price they will pay it ,that's what I did. Or just get Halfords to fit it and send their invoice.
 

DavidN

Member
This is the one I used. Shimano BB-UN26 Bottom Bracket - Black, 68-122 mm on Amazon. It was a better make than the original NECO one fitted. I think it was around £15/£20, Leon cycles were ok to pay for that one plus the labor under warranty. If you send them an invoice from yourself for the labor quoted by Halfords plus the part price they will pay it ,that's what I did. Or just get Halfords to fit it and send their invoice.
I went for this one
 

Nova Haibike

Well-Known Member
You have already done it, but there is no need to change a bottom bracket for a crank arm that has been rounded out. You only need a new arm. The aluminum crank arm is far softer than the steel bottom bracket axle.
 

DavidN

Member
You have already done it, but there is no need to change a bottom bracket for a crank arm that has been rounded out. You only need a new arm. The aluminum crank arm is far softer than the steel bottom bracket axle.
It was the bracket, same crank arm is solid, no movement, no creeks, everything now fine.
 

DavidN

Member
So Leoncycles are sending me a new bottom bracket and a new shimano altus crankset ! I know i have fitted a new bracket ( they dont know that) but do they expect you to carry out the repair ?
 

Presplan

Member
I believe they would cover the repair cost as well. They are very good at supporting warranty work. After you get your service receipt, email a copy over to them for reimbursement.