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campy square taper(5 posts)

campy square taperwooden legs
Dec 2, 2003 9:20 PM
i read somewhere that the square taper on campy bottom brackets was incompatable with most cranksets. is this true? i'm wondering especailly about the new record 10 carbon bb, i have a pair of edco competition track cranks i wanted to use with it but i'd rather not buy the bb, try it out, and have to ebay it as used merchandise. thanks for any help!
Some people here will tell you it does not matter.the bull
Dec 3, 2003 4:21 AM
Campy is ISO
Shimano is JIS
Read this from sheldon:
L_right = 18 +0.5/-0 mm
L_left = 16 +0.5/-0 mm
Dimension across flat 1.5mm from end: 12.6mm +0.02-0.05
Spindle end to bolt seat: Loose: 3mm
Tightened: 1.5mm min.

Yet another source claimed that the squares of Campa, Mavic and
Stronglight (ISO) are smaller than Shimano and Suntour (JIS) with the
result that JIS cranks will move about 4.5 mm further in.

This may conflict with the end of the square and result in a loose fit
or braking stress. for ISO cranks on JIS squares there's less contact
area between crank and spindle, since the crank does not slip perfectly
on the spindle. The result again is a higher risk of braking the crank.

But assuming those 4.5 mm and 2 deg, ISO is about 0.3 mm smaller than
JIS (2 * sin 2 * 4.5 = 0.3)?
ISO cranks (Campagnolo, Stronglight, others) won't go as far onto J.I.S. spindles as they ideally should. J.I.S. cranks (most Japanese models) may bottom out if installed on ISO spindles. In practice, you can very often get away with mixing these sizes, as long as you select an axle length that gives the desired chainline.
right spindle length??C-40
Dec 3, 2003 5:39 AM
Campy BB spindles are only 102mm long. To my knowledge, there are no other cranks out there that use a spindle that short.

As Russ detailed, the crank will also move about 4mm closer to the frame, throwing the chainline off, if the cranks have a JIS taper instead of ISO.

You better find out the required spindle length and taper standard before buying a new BB. If you have the old BB, it's easy to measure the spindle length with calipers. The end of the taper could also be measured and compared to a shimano BB, to see it has a JIS taper.
Also comes in 111 and 115.5 mm length (nm)Psalm 147-10_11
Dec 3, 2003 3:13 PM
thanks for the helpwooden legs
Dec 7, 2003 12:51 AM
thanks for the tech specs, i don't know why i'm always forgetting to check out sheldon brown's site before i ask questions here.