1x conversion - pedal arm snapped off

[Fabian46]

I measured the frame section wear the Bb and crank go...which I’m assuming is the Bb shell, and it’s 68mm.

 

Nou wat nou? Like I said...it’s never had spacers

[quickdraw]

No big deal, the self extracting bolt just need to be replaced

This, just the crank bolt that broke

[Fabian46]

This, just the crank bolt that broke

I’m a happy camper if it’s just this. I’ll go to another bike shop just now and see if they can sort it.

[the nerd]

Firstly I'd be very concerned if in fact that was the work of a bike shop... 

[droo]

SRAM BBs need one spacer each side for 68mm and none for 73. Shimano takes one on the drive side on a 73mm shell and an extra one on either side for a 68mm shell.

 

You have too many spacers. It's unlikely that this would cause the bolt to snap since the crank doesn't bottom out on the BB on the drive side, but someone didn't read the instructions.

[Fabian46]

SRAM BBs need one spacer each side for 68mm and none for 73. Shimano takes one on the drive side on a 73mm shell and an extra one on either side for a 68mm shell.

 

You have too many spacers. It's unlikely that this would cause the bolt to snap since the crank doesn't bottom out on the BB on the drive side, but someone didn't read the instructions.

Thanks Droo.

 

I’ve been using that BB with a 2x10 GXP crank for almost 4 years with no spacers.

 

Are the spacers needed purely for a 1x chainring? Because that’s all I changed. Everything else besides the DM 6mm offset chainring is as per my old setup.

[GrahamS2]

Thanks Droo.

 

I’ve been using that BB with a 2x10 GXP crank for almost 4 years with no spacers.

 

Are the spacers needed purely for a 1x chainring? Because that’s all I changed. Everything else besides the DM 6mm offset chainring is as per my old setup.

Unless you changed your BB, there should be absolutely no reason to add or remove BB spacers when going to 1x. The need for spacers is determined by, a) the width of the frame, and b) the width of the BB fitted. 

 

Looks to me like the shop was trying a hack to get the 1x chain line right, rather than fitting chainring spacers (which it the correct way of doing this).

Edited February 5, 2018 by GrahamS2

[Fabian46]

Unless you changed your BB, there should be absolutely no reason to add or remove BB spacers when going to 1x. The need for spacers is determined by, a) the width of the frame, and b) the width of the BB fitted. 

 

Looks to me like the shop was trying a hack to get the 1x chain line right, rather than fitting chainring spacers (which it the correct way of doing this).

 

Thanks. All I changed was the chainring.

 

Direct mount, 6mm offset, Oval, from RAPIDE. I made sure with Wayne that it’s the right one.

[Headshot]

They added bottom bracket spacers, take a measuring tape and measure you the bb shell width it’s either 68mm or 73mm.

 

I suspect they’ve add 2-3 spacers too many, causing the crank bolt not to be fastened correctly causing the crank arm to come loose.

 

The pictures aren’t clear if something is broken... but if you’ve got a bb tool take out the 2 spacers they’ve put in on the non drive side, tighten up everything crank arm just a bit tighter than elbow lock and off you go

Yep spot on. You only need enough spacers to ensure the chain line is correct and the crank can pull up on the axle. It looks like these Muppets used every spacer they could find in the box

[Fabian46]

Some feedback. Went to the shop this morning. Explained what I think happened to the owner. He said no problem, I must bring the bike in tomorrow and he will sort it out himself...meaning that whoever Mr Smarty pants was that did this isn’t touching it again.