thinking about getting some u turn type forks, for 100mm on the flat and ups and 120 on the downs.

the frame is rated for 80-100 forks, i weigh 12 stone, dont do silly drops but looking to do up to about 3 foot.

is this bad? anyone else do it?

Nope – got them on mine – did put them down to 100mm with 20mm spacer but going to put them back up again. I depends on your frame really – I have a Kinesis XC2 and take 90-120mm fork but best handling at 100mm. The forks work best at 120mm IMHO. What frame is it? the length of the head tube and gussetting (spelling bad) may limit fork travel and the bigger the fork the crappier it will climb.

Nah you wont die, less than a degree of head angle change, especially taking into account the little extra sag for the longer fork…

100mm travel forks vary axle to crown height by 10-15mm, you might want to check out how long the forks are your contemplating just in case they are already long axle to crown.

Might void warranty. Whether it actually produces more stress on the frame I'm not convinced…the high forces are produced when the fork is in compression.

As above change is ~1 degree for 17mm fork length. If frame is already slack then it may go too far.

You definitely will die, but it probably won't be the frame/forks that kill you.

My thoughts would be if the frame is designed for 80mm to 100mm then it might be quite a light racey frame so may not be able to withstand wha the forks are capable of. The other thought is that you should just get a good set of 100mm forks. I have found going from 100-140 that it's the quality of the forks rather than the travel that made most difference. I also happily rode everything on 100mm that I now ride on 140mm My forks got longer but my balls didn't get bigger.

This is what happened to maxlight xcpro after 2yrs with 105mm Marzocchi forks then another two and a half years with 115mm Reba forks…

Frame designed for 100mm fork… not sure if the extra travel was the exact cause of the failure, but it failed right behind the gusset weld – It did used to get hammered round Afan & Cwmcarn alot mind.

Kev

oh yeh… and I don't weigh very much either !

K

Your bike will break, and your teeth will break with it. But you won't care 'cos you'll be dead. Oh yes you will…

yes you will die in horrible pain and worst, you'll create a void that will eat the very fabric of the universe…

You'll be fine the A2C length matters more than the actual travel of the fork

The handling of the bike will change noticeably (1 deg head angle change is quite significant, don't believe anyone who says otherwise; the difference between a hard-core downhill bike and a racy XC is about 4 degrees :D), and it will probably not deliver the goods you expect: it will not climb as well, it will corner worse, and it will generally feel less stable. Also a frame designed for 80-100mm forks will likely not take kindly to you doing 3ft drops on it — by the sounds of it you need a different bike, rather than different fork.

(I gone down this route with my first MTB, and ended up buying a new frame not long after upgrading the fork; in my experience it's not worth doing.)

If you want to try it, then just try it! Don't do anything silly for the first few tries and if it seems fine then just work up from there!

The trouble with that gusset design on the MAxlight is it doesn't have open ends at the back, if the gussets don't have open ends then they may as well not be there in the first place.

My epic and and stumpjumper seem to have survived with longer forks. Just need the same at the back end to keep the Plough/stumpjumpers pedals ABOVE the ground!!