greg arnold wrote:
> Dear Listers:
>
> If someone spreads the rear stays on a vintage 60s/70s frame - Columbus
> tubing - to accommodate a 7/8/9 speed modern cassette, how much is the frame
> integrity compromised? Assuming it is done 'properly' but a pro bike shop,
> can one assume the frame will retain its rigidity and 'ride', or is it a
> terrible idea? I am considering purchasing an old frame built by one of the
> Italian Masters, and am concerned by this adjustment made by the owner.
Spreading stays from 120mm to 130mm means that each dropout moves 5mm. When I get fork blades from True Temper or whomever, they come straight. They have to be bent to offset the dropouts. The amount that chainstays and seat stays need to bend in order to move the dropouts 5mm is far less than fork blades are bent to get 40mm of rake in the fork.
In short, it's harmless, with one caveat, which doesn't apply to your old frame. Many frames built since the late 80s and early 90s are built with heat treated tubing. Often, the tubing is hard and brittle. If you try to cold set them, the tubes can crack. But the tubing on your frame is much too soft for any cracks to develope.
--
Peter Jon White
Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
603 478 0902 Phax
http://www.PeterWhiteCycles.com