rosco asked:
>>> what English threaded bottom bracket would folks
>>> suggest? I'm looking for something of only decent
>>> quality. After about a year, the parts will return to
>>> their original bike (assuming I can then afford a new
>>> Campagnolo parts
I replied:
>>I'd recommend a UN53 or UN73 68 x 115.
>>
>>See:
http://harriscyclery.net/site/page.cfm?PageID=49&Cat-
>>egory=1050
>>
>>According to my Bottom Bracket Size database
>>(
http://sheldonbrown.com/bbsize.html#dura) this crank
>>originally used a 112 asymmetrical spindle for use with a
>>68 mm BB, but with modern symmetrical bbs you want to go a
>>bit longer.
On redirect, rosco asked:
> One detail I forgot to mention...
>
> The donor rear wheel is 126mm spaced (w/ freewheel not
> cassette) whereas the recipient rear spacing is 130mm. I
> figured by changing the axle and adding some 2mm spacers
> to both sides I can make this work. Does this sound like a
> good approach given the relatively short time it will
> remain on the recipient bike?
>
> Will this approach dictate a slightly shorter bottom
> bracket spindle for the sake of chain line?
Derailer chainline is not a high-precision matter, unless
you have indexed front shifting. A 113 would probably work
too, but you might run into chanstay clearance issues or
front derailer travel issues.
If it were mine, I'd try a 113 with the awareness that it
might be too short. However, if I had to actually _buy_ a BB
without a trial fit, I'd go with the 115, which I'm sure
will work.
For road gearing, I prefer to bias the front chainline
inward to favor the big ring, as long as that doesn't cause
clearance or shifting issues. This approach allows efficient
use of more rear sprockets with the big ring, at the cost of
creating problems if you run the small chainring with the
smaller rear sprockets. Since I generally avoid those
combinations, this is a good tradeoff for me.
Sheldon "Not An Exact Science" Brown +------------------------------------------------------
---------+
| The poet Henry O'Meara (1848-1904) was my great-
| grandfather | I've put his book "Ballads of America and
| Other Poems" | on the Web at:
|
http://sheldonbrown.com/omeara |
+-----------------------------------------------------------
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9772 FAX 617-244-1041
http://harriscyclery.com Hard-to-find
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