Inbred chainset/BB width advice?
lvquestpaddler
Posts: 416
The planned easy swap of parts to the inbred from the GT avalanche didn't go as easy as I thought. Slight oversight on bb width rendered the ISIS 73x113 useless, and I'd had enough of ISIS I'm not hard on the bike but they don't last at all so decided to change it. Ordered a 68x113 ES51 Octalink BB from a seller on Ebay got it for £16 delivered. Got new Shimano M341(Acera?) cranks delivered for £13. I'd ditched the triple front set up anyway on the GT and was running a 1x9, so transfered this new-ish chainring to the new cranks. Anyway, the BB turned up today and after fitting it I had to transfer the chainring to the outer(normally 42T) position to clear the frame, but the inner chainring castings on the crank had to be hacksawed off as they were hitting the frame too. The chainring bolts needed reversed and are clearing just!
Obviously this will never go back to being a triple, but if I wanted to what size of BB fits a standard triple chainring setup?
Seems bizarre to have a narrow 68 setup and having to put a wide axle on it. Merlin only do them to 121 wide and I have doubts whether 4mm would have made any difference as the inner chainring would most likely still hit the frame. Why not make it a 73mm and have thesupported axle part wider?
As it is I've been lucky(well, haven't tested it- my weight/flex may yet cause contact?) and when the chain is on the mid cassette sprocket it's perfectly in line with the chainring. On the old GT if I backpedalled in 1/2(lowest) the chain came off!
Obviously this will never go back to being a triple, but if I wanted to what size of BB fits a standard triple chainring setup?
Seems bizarre to have a narrow 68 setup and having to put a wide axle on it. Merlin only do them to 121 wide and I have doubts whether 4mm would have made any difference as the inner chainring would most likely still hit the frame. Why not make it a 73mm and have thesupported axle part wider?
As it is I've been lucky(well, haven't tested it- my weight/flex may yet cause contact?) and when the chain is on the mid cassette sprocket it's perfectly in line with the chainring. On the old GT if I backpedalled in 1/2(lowest) the chain came off!
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Comments
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you need a 126mm axle for a standard 50mm chain line."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Cheers for that Nick, much appreciated will make a note of that!0
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that is just for that Crankset M431-8 in case anyone reads this."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0
