Hi,
Recently, after 4 months of working perfectly, I have been having problems with my left hand crank arm slipping off the axle on LX HT11 cranks. I thought this was due to the threads on the inside of the arm being stripped at one end. Having bought new FSA Moto cranks I found that the axle is only half way through the arm as it is much more noticable on these than the LX's. Again when going for a ride the crank arm fell off. I'm using these with a shimano HT11 bottom bracket.
I thought this could be due to running an E13 SRS chainguide as I have to use the ISCG mount adaptor as my frame hasn't got ISCG tabs.
Could this be acting as an unwanted spacer for the bottom bracket or have I messed up somewhere?
Any advice or help greatly appreciated?
Thanks (and sorry for the long winded explanation), Clwydrider JNR.
If your bottom bracket is 68mm wide then you should be running none of the plastic spacers between the BB bearing and the frame with the ISCG mount adaptor.
If it's 73mm wide then you should have at least one, and maybe two of the plastic spacers.
Could this be it?
wheelz, is that not the other way round?
Wheelz seems to have it backwards, normally 3 spacers on a 68mm shell(2 on drive side), 1 on a 73mm shell(on drive side) if you're running without a chain guide, remove 1 from the drive side if you are.
68mm bb with chainguide needs one spacer either side.
73mm bb with chainguide doesn't need any spacers.
Thanks everyone, I'll go and have a look now.
that in itself shouldnt be enough to make the crank arm fall off. Id check if the guide was stopping you push the cranks on far enough, depending on your cranks the inner ring tabs can be quite proud so make contact with the back plate
You are of course correct, I got it the wrong way round.
Sorry, it's been a long day!
I also had some issues getting the crank on far enough with an ISCG mount the first time I fitted them, but just used a rubber mallet to seat them properly.
Just checked and I don't appear to be running any spacers at all.
Have I got the ISCG mount on the right way round (indented side towards frame)?
Thanks.
yes thats right. did you check your cranks were sitting right up against the bb?
They seem to be right up against the bottom bracket yes.
Is there any chance it could be the axle that is too short for my bottom bracket?
Thanks.
What kind of frame is this? It's not a downhill frame with an 83mm bottom bracket is it?
It's a Mountain Cycles Rumble hardtail frame, so no just a standard 68 or 73mm bottom bracket I think.
Hmm, have you tried fitting the cranks without the ISCG plate, and measuring how much the axle protrudes on the non-drive side, then replacing the ISCG mount and seeing if this measurement is the same?
I can't see the axle being too short, as they are designed specifically to fit 68mm or 73mm bottom brackets.
Also, how are you attaching the non-drive side crank? Are you removing the inside bolt before pushing it onto the axle, then inserting and tightening the hollow plastic bolt thing into the crank before tightening up both crank bolts?
I haven't yet but will definitely try that.
Thanks for all the help!
Clwydrider JNR.