"Alan McClure" wrote:

"Mark Hickey" wrote

The change from a 63 to 80mm shock (assuming the ride height will
change by ~15mm once sag is factored in) will be between close to
another degree (probably about 0.7-8 degrees, depending on a lot of
minor things like wheelbase).

That would put your head tube's effective angle at 69 degrees - pretty
slack, but not horribly so. I doubt you'll find the difference all
that drastic though. If it's a stiffer, better fork the result will
be worth it.

I think maybe I accidentally sent you an e-mail rather than replying to the
group. So, here is what I wrote:

Do you think there is any other reasonable option--including replacing the
headtube at a frame machine shop? Would that cost an unreasonable amount of
money? I am assuming that it would, but I don't really know. It seems like
there would have to be some way around the loss of another degree, but maybe
not.

You did send me an email... here is/was my reply...

Probably not worth it unless you have an emotional attachment to that
frame that makes it worth spending much more than it's worth to
upgrade it. I'd recommend trying the shock and see if you like the
results. If that doesn't work out, there are plenty of frames out
there that you could buy with appropriate angles (and that are
probably lighter and stronger to boot).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame