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Frame cut

PostPosted: Sun Jun 05, 2016 4:17 pm
by gizmo
Want to cut an Li frame to suit GP bodywork, any advice or is it just a matter of cutting 20 odd mil off and getting steering race turned down to fit.

Re: Frame cut

PostPosted: Sun Jun 05, 2016 5:20 pm
by ToBoldlyGo
Swap it for a Spanish frame.

Re: Frame cut

PostPosted: Sun Jun 05, 2016 6:03 pm
by Digger
ToBoldlyGo wrote:Swap it for a Spanish frame.


That isn't going to help him.

Re: Frame cut

PostPosted: Sun Jun 05, 2016 6:13 pm
by gizmo
It is a Spanish frame. I was going to do it as a special but my love of GP's has got the better of me. It owes me too much to sell it and it's been altered to take an aero filler cap

Re: Frame cut

PostPosted: Sun Jun 05, 2016 6:19 pm
by MickYork
I think you're right, cut the fork stem down and job done.

I would consider offering it up as a swap though, as the fact the log book will always be Li and it will look like a GP, might worry some people

Re: Frame cut

PostPosted: Sun Jun 05, 2016 6:47 pm
by modster79
I did it years ago, used a pipe cutter that cost a couple of quid to cut the stem. The pipe cutter gives a good straight cut.

Re: Frame cut

PostPosted: Sun Jun 05, 2016 11:56 pm
by Knowledge
Hold on, it is not quite that simple.

The top of the steering column tube is machined at the top to a depth of about 15mm to suit the GP top steering bearing race. When you cut the top off the steering column tube, you lose this machined recess. When you offer up the bearing track, it doesn't fit. It is too big and hardened, so it is very difficult to machine.

To overcome this, I used a chrome ring and associated bearing, which has a smaller OD. I then cut all the ring off (except the lug that forms the steering-lock stop) so it becomes an adaptor between the cut-down steering column tube and the bearing race. I do this by machining-down the outside of the remaining chrome ring to match the ID of the inside of the steering column tube. I hope that makes sense.

It is a bit of a waste of a chrome-ring, but it works.