BB Sizing question-- English threads and 70mm width?

I'd think a Phil Wood BB would work well regardless. Just get one with the length axle you have now
(or perhaps a bit shorter if you want) and use the english thread lock rings. Also, you can swap out
the Phil BB itself for a Shimano UN-72 (Italian threaded @ 70mm) and it will fit the Phil lock rings
nicely once you remove the right side cup. This will save some money although the Phil BB is likely
to last far longer.

David

Jim Rogers said:

I have an old Nishiki Olympic 12 on which I would like to change the bottom bracket. However, I'm
confused on the sizing for this particular model.

It currently has an old non-cartrige bb bracket. I took that out, but I don't know what size cartrige-
type to replace it with. The threads are definitely English (right side threads are left-handed
and an English-threaded Chorus bb I have fit into the threads on both sides perfectly).

However the shell is definitely 70mm (checked with callipers and compared directly to another bike
with 68 mm shell). Do they make 70mm bb's with English threads? I'm only aware of English in 68
and some 73 and Italian in 70.

One thing I thought of was that maybe the shell had never been faced (I got the frame used, so I
don't know the history). But I looked at the spindle of the old bb, and it's really long, even
though the bike is a double, not a triple. The overall length (excluding the threads on the ends)
is about 128 mm, and the cones are substantially farther apart than those on an old Ultegra
spindle I have that came out of a 68mm shell.

This leads me to believe that the 70mm width is correct.

So the question is-- Is there a bb I can use in this shell? If not, should I have my LBS face the
shell? Or is it possible that the shell is 70mm for some reason and should not be shortened?

Thanks,

Jim

Jim Rogers said:

I have an old Nishiki Olympic 12 on which I would like to change the bottom bracket. However, I'm
confused on the sizing for this particular model.

It currently has an old non-cartrige bb bracket. I took that out, but I don't know what size cartrige-
type to replace it with. The threads are definitely English (right side threads are left-handed
and an English-threaded Chorus bb I have fit into the threads on both sides perfectly).

However the shell is definitely 70mm (checked with callipers and compared directly to another bike
with 68 mm shell). Do they make 70mm bb's with English threads? I'm only aware of English in 68
and some 73 and Italian in 70.

One thing I thought of was that maybe the shell had never been faced (I got the frame used, so I
don't know the history). But I looked at the spindle of the old bb, and it's really long, even
though the bike is a double, not a triple. The overall length (excluding the threads on the ends)
is about 128 mm, and the cones are substantially farther apart than those on an old Ultegra
spindle I have that came out of a 68mm shell.

This leads me to believe that the 70mm width is correct.

So the question is-- Is there a bb I can use in this shell? If not, should I have my LBS face the
shell? Or is it possible that the shell is 70mm for some reason and should not be shortened?

There were indeed 70mm BSC threaded BBs from Nishiki and also Sekine. What is the spindle marking in
your original, a type 3-S or a 5-S? Three denotes a 68, five a 70mm shell.

For the one millimeter chainline error, I'd just install a normal BSC BB and see what happens. I
assume you do not want to pay for frame machine service if you can help it.

If the gear train shifts well with a one millimeter right offset ( and it most likely will) then you
actually do not have a problem, just a curiosity.
--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

irene-<< It currently has an old non-cartrige bb bracket. I took that out, but I don't know what
size cartrige-type to replace it with. The threads are definitely English >><BR><BR> << However the
shell is definitely 70mm (checked with callipers and compared directly to another bike with 68 mm
shell). Do they make 70mm bb's with English threads? I'm only aware of English in 68 and some 73 and
Italian in 70. >><BR><BR>

No 70mm english BBs, it's just made poorly, IMO-If the chainline is not affected hugely, just use a
68mm BB. Or have the BB shell faced a wee bit, a good idea anyway, and it will be closer to 68mm.

BB spindles are matched to cranks. A long BB with a double designed for that is not uncommon.

irene-<< So the question is-- Is there a bb I can use in this shell? If not, should I have my LBS
face the shell? Or is it possible that the shell is 70mm for some reason and should not be
shortened? >><BR><BR>

Have it faced and use the BB that matches the crank you wish to use.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"