How to change the chain rings on Shimano Octalink Cranks
Steve_b77
Posts: 1,680
As some may have noticed I'm planning on changing the middle ring on my crankset for a 36T one - this arrived this morning.
My cranks set is a Shimano Octalink FC-M521 which is OEM on my Specialized Pitch Comp.
The big question is how do I change it, do i have to remove the crank arm and if so, how do I do it :?:
The only thing I can find on the web is this Shimano FC-M521 Exploded view
And it doens't really say how to change the rings.
Any ideas would be fantstic as I wan to do this myself if possible
My cranks set is a Shimano Octalink FC-M521 which is OEM on my Specialized Pitch Comp.
The big question is how do I change it, do i have to remove the crank arm and if so, how do I do it :?:
The only thing I can find on the web is this Shimano FC-M521 Exploded view
And it doens't really say how to change the rings.
Any ideas would be fantstic as I wan to do this myself if possible
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Comments
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Its easier to do with it off. But can be done with it on. Undo the chainring bolts (may need something to grip the nut at the back, especially when retightning), slide off, and replace! Make sure you put it on the right way round, and right way up.0
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I can't get the middle chain ring past the 4 legged bit on the end of the crank arm shown as part 10 on the exploded view in my link, does this mean I have to follow this :arrow: Park tools Octalink Removal
And buy a crank removing tool?0 -
have a look at parktools. linky below."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
usually if you rotate by 45 degs then slide past the spider and along the leg. Should be doable if the outer ring is off.0
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Looking at the PDF, undo the bolts fully and remove the bolts from the spider and ring. Lift the chainring over the spider opposite the crank arm then slide down the crank arm and off. Looks that simple from the PDF, but might not be in reality.I've added a signature to prove it is still possible.0
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are the main crank bolts 8mm or 10mm?
the newer HTII you do need to remove the crank from the bb due to the spider design while on the older HTI it was not needed to do this. Now as this is a newer HTI and the spider part does look similar to the newer HTII so you may hve to remove the arm."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
The bolt uses a 8mm allen key to remove it, I think the crank arm is going to have to come off.
Are the crank removal tools cheap enough or shall I just get LBS to do t?0 -
if the crank arm is 8mm is it not self extracting?"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Steve_b77 wrote:The bolt uses a 8mm allen key to remove it, I think the crank arm is going to have to come off.
Are the crank removal tools cheap enough or shall I just get LBS to do t?
You can get a cheap one from halfords for about £8, did the job for me nicely or the parktools one is about £12 i think. Worth buying the part as you willmore than likely have to have them off again in the future for BB maintenance or replacing parts.0 -
Looks like a trip to halfords is in order then0
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Sorted one Crank puller purchased, crank taken off, chain ring changed from 32T to 36T, cranks re-fitted and torqued to pretty tight using 3/8ths drive.
Out for a little test ride up & down the road and the shift from Granny to new middle ain't too bad, a bit noisey but fine considering it's a 22T to 36T move.
It doesn;t want to shift to the big ring, but thats no biggie as thats coming off anyway, I'd suspect it's down to the 36T and the 42T being much closer in overall diameter.
Might just go and give it a good thrashing through the forest now - or watch the footie :?0
