I have an old heckler from 2000, if I put some Pikes on it and wind them out to 140mm, apart from the headangle issues, will the leverage issue cause major failure of the frame or can it take it?

I had one of them with sids …. 80mm sids at that …. it handled good….

i cant see it working well with 140 even on dh's and well jumping and landing i can see headtube bye bye …

Why bother – stick to about 120 max – even thats pushing it – was designed for 100mm

Been running it with an old set of dukes (80mm) and yeah it is a lot of fun.

Going to run them turned down to 110, so should be fine. I was just curious, they are a future-proofing purchase against a frame upgrade in the summer but seems a shame not to use them. 😉

It's not about travel it's about axle to crown length. Lots of forks these days have longer travel but aren't much longer axle to crown.