kirke

Hi there,
I purchased a used track bike off of my local craigslist and it came equipped with a set of old (151 BCD) Campagnolo track cranks mounted on a Shimano bottom bracket. I have since replaced the Shimano bb with a modern Campy one. However I am having some chainline issues...my question is:
Since Shimano and Campagnolo bottom bracket spindle tapers are different, is there a chance the taper of my Campy cranks are now messed up from being mounted on a Shimano spindle?

Thanks in advance!!
Kirke

Old Fat Guy

Doubtful, probably the wrong length spindle. If the chainline was correct before, get a BB with the same length spindle.

JohnDThompson 

No; they should be fine. The tapers are the same, just the length of the tapered section is different.

Road Fan

I think you can find the correct BB length and possibly the part on the Bicycling Classics website. Getting that should eliminate any possibility of chainline problems.

Grand Bois

They all have the same 2 degree taper angle.

delicious

Does anyone have any hard evidence they can point to on the taper being the same but for different lengths? It's something that comes up a lot. I'd really appreciate it.

Old Fat Guy

Look in Sutherland's Manual.

cyclotoine

Martin Trautmann posted on rec.bicycles.tech:

L_right = 18 +0.5/-0 mm
L_left = 16 +0.5/-0 mm
Dimension across flat 1.5 mm from end: 12.6 mm +0.02-0.05
Spindle end to bolt seat: Loose: 3 mm
Tightened: 1.5 mm min.

Yet another source claimed that the squares of Campa, Mavic and
Stronglight (ISO) are smaller than Shimano and Suntour (J.I.S.) with the
result that J.I.S. 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 J.I.S. 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
J.I.S. (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.

cs1

The angle is the same yes. But the length is different. Unfortunately the crank will never work as intended because of that.
https://www.bikeforums.net/road-cycling/451838-bottom-bracket-size-campy-cranks-shimano-bb.html
https://www.sheldonbrown.com/bbsize.html

kirke

Thanks for the responses everyone.

I actually just got a really good deal on a NOS Miche track crankset and bottom bracket. So those will be going on the bike and the Campy cranks will be coming off (I want to save these old guys for a more classic track frame.)

But thankfully, now I understand tapers a little better for next time I am dealing with a mitch-matched set!

Thanks again,
Kirke

John E

Actually, old SunTour cranks and spindles followed the European sizing standard -- Shimano was the odd man out. Sometime in the early-to-mid 1990s Campagnolo reportedly switched over to the Shimano standard, and I actually cracked a Campagnolo Veloce crank, evidently by mounting it onto a slightly newer cartridge-style BB, naively having thought that I would be safe staying with a single brand of parts.

pcrman

Two finicky mechanics told me not to put a campy chorus crankset onto a shimano BB (on my mid-80's peugeot) due to different taper specs. Yet another mechanic told me it would work fine, but that the taper was different but I shouldn't have any problem.
I went ahead, mostly since the campy stuff was given to me by a friend, and I have around 600 miles on it with no problems, still solid as hell. BTW, I am 5'11 and 205, and I mash.

cudak888 

It so happens I was presented with the JIS/ISO dilemma today with a Shimano 600EX BB w/JIS taper and a new Campagnolo Record track crankset running the ISO taper. The difference in the amount of taper that was not engaged - loose - was about 2mm (in comparison with the original 600 crankset).

In this particular case, I let it slide. The Record crankset seated quite nicely when mounted. The difference, once mounted, was about 1mm, eyeballed. I let it at that.

-Kurt