Cracked crank arm, thought it was Ultegra but...

I posted earlier about having a cracked Ultegra crank arm on an 88 Trek 1500 but on closer
examination discovered it's a Specialized crank rather than a Shimano 600. Apparently the hubs and
crank are Specialized and the rest of the components are Shimano 600. Does anyone know if I can
replace my Specialized crank with Shimano 600 or Ultegra? I can't find any identification marks on
the crank arms other than the word Specialized on the chain rings.

 

"BillX" <[email protected]> wrote:

> I posted earlier about having a cracked Ultegra crank arm on an 88 Trek 1500 but on closer
> examination discovered it's a Specialized crank rather than a Shimano 600. Apparently the hubs and
> crank are Specialized and the rest of the components are Shimano 600. Does anyone know if I can
> replace my Specialized crank with Shimano 600 or Ultegra? I can't find any identification marks on
> the crank arms other than the word Specialized on the chain rings.

With respect to the interface between the crank and the spindle, the only issue is the fit of the
tapers. Everything out of Japan uses the same standard, so yes, you can safely put a Shimano crank
on there. Specialized-label components are from the mysterious East. Someone else here can tell you
what factory made them for Specialized.

If the only Specialized marks are on the rings, that does not mean that the cranks are also
Specialized, but that's probably a good bet.

A potential complication is that various cranks will place the rings and pedals at various positions
relative to the end of the spindle and thus may alter pedal tread ("Q factor") and chainline. I'd
suggest taking the old cranks with you to the shop to make a comparison. If the relevant dimensions
are not the same you might need a different length spindle to avoid problems such as the inner ring
interfering with the chainstay.

--
Ted Bennett Portland OR

 

I have the same bike and replaced the specialized crank and bottom bracket with a 7 year old DuraAce
crank and an ultegra cartridge bottom bracket. I was surprised at how much stiffer the cranks felt
out of the saddle. If you want the Specialized crank email me. I still have it and the bottom
bracket. Bill Brannon remove the nospam stuff to reply

"BillX" <[email protected]> wrote in message news:[email protected]...
> I posted earlier about having a cracked Ultegra crank arm on an 88 Trek
1500
> but on closer examination discovered it's a Specialized crank rather than
a
> Shimano 600. Apparently the hubs and crank are Specialized and the rest
of
> the components are Shimano 600. Does anyone know if I can replace my Specialized crank with
> Shimano 600 or Ultegra? I can't find any identification marks on the crank arms other than the
> word Specialized on the chain rings.

 

"BillX" <[email protected]> wrote in message news:<[email protected]>...
> I posted earlier about having a cracked Ultegra crank arm on an 88 Trek 1500 but on closer
> examination discovered it's a Specialized crank rather than a Shimano 600. Apparently the hubs and
> crank are Specialized and the rest of the components are Shimano 600. Does anyone know if I can
> replace my Specialized crank with Shimano 600 or Ultegra? I can't find any identification marks on
> the crank arms other than the word Specialized on the chain rings.

You can't replace it with a new Ultegra crank because Shimano now uses a different kind of spindle
(a round pipe instead of a square taper). Even if you get a crank that uses a square taper (there
are many still available) you might need a new bottom bracket. If you have the wrong length of
spindle for your crank, you could mess up your chain line or it may not work at all (e.g., if the
chain rings are brought in so close that they hit the chain stays).

Single replacement crankarms are available from some distributors. If you take your bike to a shop,
they may be able to find you a replacement.

 

In article <[email protected]>, Gary Young
<[email protected]> wrote:
>"BillX" <[email protected]> wrote in message news:<[email protected]>...
>> I posted earlier about having a cracked Ultegra crank arm on an 88 Trek 1500 but on closer
>> examination discovered it's a Specialized crank rather than a Shimano 600. Apparently the hubs
>> and crank are Specialized and the rest of the components are Shimano 600. Does anyone know if I
>> can replace my Specialized crank with Shimano 600 or Ultegra? I can't find any identification
>> marks on the crank arms other than the word Specialized on the chain rings.
>
>You can't replace it with a new Ultegra crank because Shimano now uses a different kind of spindle
>(a round pipe instead of a square taper). Even if you get a crank that uses a square taper (there
>are many still available) you might need a new bottom bracket.

Specialized made spindles with Shimano-compatible taper but the two I have had (from 1980s) are both
like a Campy taper and the Specialized crank I had fit perfectly on a Nuovo Record spindle. If stuck
on an ISO taper spindle it would fit like a Campy crank. And it was a 144mm BCD crank. I speculate
they turned to the ISO taper after they went to 130mm BCD.

--Paul