Shimano LX BCD, please help

[Sidmouth]

Im converting my sons 26er with a 3x9 to a 1x11 with my old Shimano group set, Just stuck on what BCD theses old Shimano LX cranks where , any ideas would be greatly appreciated.

 

[Fox3]

Big and middle rings 94, granny 58.

[Fox3]

You could measure also, in case I'm wrong.

[Sidmouth]

Thanks Fox3

Now do you measure BCD, thanks in advance.

[Fox3]

No worries. I think if you measure from more or less the centre of a bolt hole to the centre of a bolt hole directly across from it (if there are 4 bolts as they are then across from each other) then you should get it, or if you measure to the centre of the crank you have the radius then double (could work for 4 and 5 bolt perhaps).

[WrightJnr]

My sons bike I put old LX cranks on and a 1X10. His is 104BCD when using the outer spider. They were the octalink LX cranks.

 

 

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[WrightJnr]

https://www.wolftoothcomponents.com/pages/how-to-measure-bolt-circle-diameter-bcd

 

 

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[Sidmouth]

https://www.wolftoothcomponents.com/pages/how-to-measure-bolt-circle-diameter-bcd

 

 

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this is a great chart, thanks guys

[Sidmouth]

OK last question, would it work if i kept the original 9 speed middle ring with an 11 speed chain, Im thinking the thicker ring may actually keep the chain on better, as i understand it lots of 9/10/11 are compatible

[dirtypot]

OK last question, would it work if i kept the original 9 speed middle ring with an 11 speed chain, Im thinking the thicker ring may actually keep the chain on better, as i understand it lots of 9/10/11 are compatible

 

Yes, it would work - just not great for chain retention.  NW ring is a lot better.

[FrikkieMeyer87]

Ditto to the above. On my 3x9, the middle chainring is 32T just like the one I'm replacing it with, however the replacement is a 1x specific 32T narrow-wide 104BCD which is a bit more resilient in terms of keeping your chain where it needs to be as well as put up with being the only recipient of wear to the front of your drivetrain (bit more beefy). If you're doing 42 at the back though and plan on doing trail rides, ideally I believe you'd rather want a 30T chainring to maintain the ratio of the granny gear you had on the 3x9. I want one also, but couldn't find one on the hub in time

[Sidmouth]

Yip, a specific 1x ring would be ideal and in a 30T or 28T, 

I think this is the one on CRC 

I must just double check the BCD with that chart I was sent.

 

http://www.chainreactioncycles.com/s?q=chainring&f=4294963494,4294909240,4294266849

[WrightJnr]

You can you the original ring to "test out" the one by setup. But trust me, the combination of a chainring designed to help shift a chain left and right and a non clutch rear mech will result in endless chain drops. Narrowwide chainring at a minimum. Add a clutch mech and happy days.

 

 

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