On lfs the ffb is really weak on my wheel for example i cant feel anything raging from kerbs to even crashing. Rfactor gives out ffb and even race 07! however on LFS its just nothing.

Have you tried turning up the FFB strength? It's in Options - Controls - Force strength. Or when driving, press < and > (, and .) to increase/decrease the force.

Yes but the steering gets extremely heavy and still no ffb :/ anyways will keep trying to fix it somehow. If anyone has more suggestions please say.

Just recently I reinstalled LFS and the logitech profiler for my G25 after a system rebuild.
I had no FFB effects as you described.
I uninstalled the logitech profiler software, disconnected the wheel from the USB port.
Reinstalled the Logitech software and only plugged in the G25 when prompted.

After that I had ffb resistance to turning the wheel, but still no effects from kerbs, crashes etc...

I got mine back by going into the LFS options, controllers section and switching my controller over to keyboard, joined the track, and then went back into the controllers section and reselected the G25 wheel as the controller.

After that just reclaibrated the wheel and it's been fine for the past few weeks.

So give that a go, and maybe backup all your LFS skins/setups etc and reinstall LFS as well, if my above solution doesn't work.