BB with Chorus crankset?

I just purchased a second-hand 9/10 speed Chorus crankset, not sure of the
exact vintage, but it looks very much like the current aluminum model. Can
I use a 107mm (single speed chain line is perfect) square taper Shimano
bottom bracket with this, or does it HAVE to be a Campy BB?

TIA!

Basjan

On Tue, 23 Aug 2005 18:01:40 +0200, "Jean Pasquet"
wrote:

A 107 mm Shimano = chainline with Chorus of 111 mm; but, Chorus is a
102 chainline.

I think that the older Chorus cranks, that used a spindle, do fine
with a 111 ISO or 107 JIS. I recall that they frequently don't say
Chorus on them.

On Tue, 23 Aug 2005 18:58:32 +0200, "Jean Pasquet"
wrote:

I think that the older Chorus cranks, that used a spindle, do fine
with a 111 ISO or 107 JIS. I recall that they frequently don't say
Chorus on them.

Yes, it is !
But, it's old !
How years ?

I have a crankset that I think is a 1991 vintage. There is no Chorus
logo and the cranks use a self extracting hex bolt that uses a 7 mm
hex key. This crankset would use a Campy 111 bb, i.e. AC-H. A 'b'
fit would be an JIS 107 mm.

"Jean Pasquet" wrote in message
news:mn.bc397d588fc99c1f.20929@Cycles...
Bonjour,
Basjan a écrit dans son message :

I just purchased a second-hand 9/10 speed Chorus crankset, not sure of
the exact vintage, but it looks very much like the current aluminum
model. Can I use a 107mm (single speed chain line is perfect) square
taper Shimano bottom bracket with this, or does it HAVE to be a Campy BB?

No !
Shimano bottom bracket is square JIS and Campagnolo is ISO.
A 107 mm Shimano = chainline with Chorus of 111 mm; but, Chorus is a 102
chainline.
It is thus necessary to put a bottom bracket of 102 Campagnolo or
Stronglight, for example.

The chain line is sorted out, since it a single speed with a little more
options in "line choice" than a geared bicycle. But the spindle-fit itself
is what I am interested in. I just did a quick fit-test (Chorus crankset
with Shimano BB) and it seems fine?!

Basjan

Paul Kopit wrote:
On Tue, 23 Aug 2005 18:01:40 +0200, "Jean Pasquet"
wrote:

A 107 mm Shimano = chainline with Chorus of 111 mm; but, Chorus is a
102 chainline.

I think that the older Chorus cranks, that used a spindle, do fine
with a 111 ISO or 107 JIS. I recall that they frequently don't say
Chorus on them.

If it's a '9/10s' crank, then made 1997 and later and indeed used a
ISO, 102mm spindle. Chorus that used 111mm was last made in 1994.

Basjan wrote:
I just purchased a second-hand 9/10 speed Chorus crankset, not sure of the
exact vintage, but it looks very much like the current aluminum model. Can
I use a 107mm (single speed chain line is perfect) square taper Shimano
bottom bracket with this, or does it HAVE to be a Campy BB?

TIA!

Basjan

Using a larger shimano taper will enlarge the taper of the crank, not
the best solution. Ideal is the 102mm Campag taper BB.

"Qui si parla Campagnolo" wrote in message
oups.com...

Basjan wrote:
I just purchased a second-hand 9/10 speed Chorus crankset, not sure of
the
exact vintage, but it looks very much like the current aluminum model.
Can
I use a 107mm (single speed chain line is perfect) square taper Shimano
bottom bracket with this, or does it HAVE to be a Campy BB?

TIA!

Basjan

Using a larger shimano taper will enlarge the taper of the crank, not
the best solution. Ideal is the 102mm Campag taper BB.

Not to be a stickler, but I found this on Sheldon´s site:

"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. "



Since I have a longer (107mm JIS) than required (102mm; ISO) axle on there,
does that mean that the combination of Chorus x 107 JIS will at least be
safe?

Thanks again.

Basjan

Basjan wrote:
the best solution. Ideal is the 102mm Campag taper BB.

Not to be a stickler, but I found this on Sheldon´s site:

"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 longas
you select an axle length that gives the desired chainline. "



Since I have a longer (107mm JIS) than required (102mm; ISO) axle on there,
does that mean that the combination of Chorus x 107 JIS will at least be
safe?

It'll be safe. I have done this a few times, use a Campag crank on a
shimano BB, for a variety of reasons, mostly because the crank flats
had been largened by the larger BB spindle.