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So my commuter has an ancient Deore LX (Octalink 1) chainset on it.
44-32-22 tooth. Cranks are stamped FC M571 and it backs onto an equally ancient but working ES71 bottom bracket.
It needs new chainrings. The current ones are like wood saws. But I can't seem to find replacement rings anywhere.
What are my options here?
CRC have an M570 set going for just £29 which seems like a bargain
http://www.chainreactioncycles.com/Mobile/MobileModels.aspx?ModelID=86411
but it is a 170mm crank instead of my current 175. Would I notice that difference? How does the 570 compare to my 571?
Or should I bite the bullet and take the opportunity to upgrade to Hollowtech or maybe even move to SRAM?
(It is mainly a commuter and only a very occasional mountain bike!)
Thoughts please.
No need to buy new cranks. Any 4-bolt chainrings will do. You should be able to find them easily enough.
might be cheaper to buy a chainset, use the rings, then sell the arms on ebay.
Bez: ah cheers, so are all the 4 bolt shimano interchangeable then? I wasn't sure as the look quite different and where the bolts are on the outer sort of matches up with the shape of the spider on the cranks.
that crc chainset wil be the cheapest way of getting new chainrings. You may need to file a bit to get to fit WCS.
I took a big ring off a tiagra octalink chain set last week and you can have that but I've just been out and checked - it's five bolt and 52 teeth. Sorry!
Thanks anyway paul.
Does anyone know how much of a difference it would make if I just used the whole M570 crankset.
Seems a shame to split it and not to replace my battered cranks with shiny new ones, but I'm not sure what the differences are between them in terms of weight etc or whether the170 crank length will be noticeably different from my current 175.
As Al said above, you'll be very lucky to find new rings cheaper than that.
As for the cranks being 170 instead of 175, I'd get them and try them as they are. If they feel too short, swap the rings over and continue with the old crank and sell the new arms.
Yep fair enough. Cheers all.
Ah just realised the M570 is square taper not octalink - so guess I'll just buy it, scavenge the rings and ditch* a perfectly good pair of cranks.
(* by "ditch" I obviously mean "store at the back of the shed just in case")
I doubt you'll notice 170
I'd upgrade to ht2
The M570 rings are a smart move at that price. Worth noting that a replacement middle ring costs about a tenner new and outers can be found cheap secondhand when people ditch them in favour of bashguards. If you've worn out the inner ring you're doing something wrong.
I've got a choice of 2 spare unused Deore 44t outer rings (1 silver, 1 black) that i'd sell at £12 (each) posted?
Then get a cheap 32t middle ring and you're done (assuming that the granny is unlikely to need replacing as it's generally not used much on commuter bikes).
Doh too slow. Thanks anyway MrTall, but I've pushed the button on that M570 set (plus a new cassette, chain and jockey wheels!)
matt: thought about making the upgrade but can't really see the point. Current BB works fine and has done for years. Plus Hollowtech seems to require getting the frame faced and fiddly installation.
Maybe if it saw more mountains but it is chiefly a commuter and family pootler.
Get the Deore HT2 crankset with all new rings and BB for about £50
so are all the 4 bolt shimano interchangeable then?
Except XTR, which is odd.
Measure accross two opposite holes, centre to centre. This is called the bolt-circle diameter (BCD) Look for other rings with the same BDC. Shimano, Middleburn, Blackspire, Raceface, etc,etc all do them in this size (can't remeber off the top of my head, maybe 104mm? For big and middle anyway, smaller for granny)