|Use Campagnolo bottom bracket for older Shimano cranks?||hphoto|
Sep 28, 2003 1:25 AM
|Actually I have a Mavic 631 crankset which uses tapered spindle bottom bracket (like the older Shimano cranks). I need a new bottom bracket (italian thread).
Can I use Campy bottom brackets? Are their tapered spindles compatible with older Shimano cranks?
|If it worked it would not be good.||the bull|
Sep 28, 2003 3:51 AM
|The tapers are different and it could weaken the crank.
Check out thishttp://www.sheldonbrown.com/bbsize.html#shimano:
|Rusty's right, the bull is wrong! (nm)||Kerry Irons|
Sep 28, 2003 5:37 PM
|This info is from Sheldon Brown's site.||the bull|
Sep 29, 2003 3:46 AM
Traditional cotterless cranksets use a tapered square axle end. The sides of the end taper at a 2 degree angle compared to the centerline, 4 degrees compared to each other.
While there is general agreement about the angle, there is no such agreement about the actual width cut off.
ISO vs J.I.S. Standard
Martin Trautmann posted on rec.bicycles.tech:
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.
|Try reading it ALL.||Rusty Coggs|
Sep 29, 2003 5:26 AM
|Read the last sentence. It's exactly what I said. I've done it as have others.|
|Why are you guys jumping on my back?||the bull|
Sep 29, 2003 8:31 AM
|Sure you can do it, but mixing ISO and JIS is not good.
Either you are forcing the crank on the wrong spindle or it is going to bottom out on the wrong spindle.This could cause crank damage.
Reread my post!
I am not wrong here.
Rusty, your not wrong here.
Whats the deal!
|I think this is a case of the right answer vs a good enough one.||russw19|
Sep 29, 2003 1:50 PM
|Bull is right. Rusty is close enough. Does it really make a difference? Some say yes. They would be the ones looking for the "correct" or "right" answer. Others say no. They would be the ones who would say that it happens all the time so it's no big deal.
"Just because you can do something doesn't make it a good idea. You can drive a car with your feet, but that doesn't mean it's to be done!" - Chris Rock
|re: Why are you guys jumping on my back?||_jim_|
Sep 29, 2003 6:41 PM
|perhaps it's because, you're a jerk? ... note to readers - bull's reply will feature a reference to his veloce review, no doubt...|
|Whats a matter?||the bull|
Sep 30, 2003 3:41 AM
|Mommy and Daddy did not get you the tricycle you wanted?
Maybe we can take your little red wagon and fill them up with all the funny jokes you tell here! To bad its still empty.
Want a cookie?
Are your feelings hurt, I am sorry.
Dont worry Jim you will be OK!
|re: Use Campagnolo bottom bracket for older Shimano cranks?||Rusty Coggs|
Sep 28, 2003 5:35 AM
|Where does this Shimano stuff come in??? Suppose your Mavic crank has a ISO taper like campy?? JIS(shimano and most other oriental) and ISO(campy0 tapers are the same 2*,but the iso starts and ends a bit smaller, so a shimano crank on an Iso taper slides on a bit further than it should, and an iso crank arm on an jis taper does not go on quite as far as it should....The mismatch is more technical than anythng.Main point being that the chainline may not be exact,but that assumes you don't account for the mismatch bu using a slightly different spindle length to account for the mismatch and position the crank acordingly, and once you run the mismatch with a given set of crnks you should not go back the other way.... Many have run the mismatch both ways without even realizing it and suffered no consequences.|
|Don't do it!||MShaw|
Sep 29, 2003 9:57 AM
|I had a b1tchin Mavic crank that I put on a Shimano BB. Craaaack! There went my b1tchin Mavic cranks.
From what I understand, Mavic cranks have a different taper than most anything else out there.
I saw a Mavic Italian BB on ebay the other day. Might wanna go check there. California Bicycles in La Jolla has a few Mavic BBs hanging around too.
I still miss that crankset!
Sep 29, 2003 8:07 PM
|I love my Mavic crankset too (and the Mavic bottom bracket). I use a Mavic bottom bracket with it on my current bike, and I really want to use the crank on a new frame. But if it means that I have to use the Mavic bottom bracket, I don't want to have to shave the bottom bracket shell of the frame as required for mavic bottom bracket installation.
My other option was to find an old(er) Shimano bottom bracket for the Mavic crank - but now I know not to consider that option. Thanks for the info.
And thanks to everyone's tips and info.
I guess I will have to look for a new crankset and bottom bracket for the new frame. I will surely miss my Mavic crank and bb. It's too bad Mavic did not continue to make components and groupos.
|Mavic BB/crank||Rusty Coggs|
Sep 30, 2003 5:30 AM
|Isn't it iso taper,and if so why not find a campy or other iso BB of the correct length? I have a Mavic crank and BB and from a quick maesurement of the ends of the tapers it appears to be the same as a campy and smaller than shimano JIS.|| |