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Moulton MK3 Crankset Replacement Questions

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Moulton MK3 Crankset Replacement Questions

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Old 01-09-19, 11:28 PM
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Veem
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Moulton MK3 Crankset Replacement Questions

Hi All,
I am sorting out an otherwise stock 70's Moulton MK3 for a friend and want to replace the worn out steel cotter pin cranks with an old pair of Campagnolo Nuovo Record road cranks fit with a single 50 tooth 1/2 X 1/8 pitch chainring.
What I have determined is that the MK3 uses a Raleigh BB standard with a 73mm shell width and cups with 26 TPI threads. It looks like the path of least resistance is to use a Phil Wood spindle and a set of their 26 TPI cups.
Does anyone have any first hand experience on this modification? I am looking for information on the length of the spindle needed for proper chainline with the stock 3 speed hub and rear spacing. Also, who makes an affordable 50T chainring that will fit Campy Record work with an 1/8 inch chain?

Any suggestions would be welcome. BTW, I am not interested in retaping and narrowing the width of the BB shell.
Thanks, Veem
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Old 01-10-19, 07:58 AM
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Originally Posted by Veem View Post
who makes an affordable 50T chainring that will fit Campy Record work with an 1/8 inch chain?
Any 3/32" or 1/8" ring with the proper BCD (I assume 144mm for vintage Campagnolo Record arms) will work with 1/8" chain. There's seldom any shortage of them on e.g. eBay:

https://www.ebay.com/b/Road-Bike-Rac...11/bn_72012992
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Old 01-10-19, 04:22 PM
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Measure the chainline of the rear cog, the frame center to the cog dimension. With this then call Phil with the crank arm/ring you intend to use and let them advise you WRT the BB length. Do know that Campy has had changing designs WRT where the tapered hole is relative to the ring(s).

You could also mount the Campy crank/ring on a known Campy BB (and likely not on the Moulton) and measure that chainline. Then do the math to extrapolate to the Moulton's needs. Andy
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