I have a vibbration when i am traveling at 85-95kmph. I have had my tail sharft ballanced with new universals, I have allso had new tyers put on and ballanced .The vibe happens in gear or out of gear @ those speeds only, otherwise the car is good after 95 or before 85 .could my brake disks be the prob, they do vibe if i apply brakes,could they be the vibe if i am not using them[/b]

check for warped disks,usually the front,engine and gearbox rubber mounts,the gearbox extension has a white metal bush that supports the tail shaft drive yoke,front suspension may be worn-----hard to pin point with no details,thats all the possibles---may have missed some.front disks the run out if more than .002 will pulse the brake pedal,more than that you can really feel it and you will know it.

I'd say warped discs. Pretty common.

Is the car lowered?
Paul

does it only shudder at those speeds when ON the brakes? if so.. disc's are warped..

it sounds like wheel balance to me. you could have lost a weight or they might have messed it up when they balanced them. if the vibration is through the steering wheel it is probably you front wheels/end. if you feel it through the seat it is probably in the back wheels/end.
i have a small vibration even after balancing the wheels because i have rubbish tyres and one isn't quite right.

I'd say wheel balance, or the bush in the extention houseing. jump under the car grab the tailshaft at the gearbox end and shake it up and down... if there is play its fkd or has slip out when you where putting the tailshaft back in.

+1 on this question, could be pinion angle, it's around the speed it tends to happen.
Also what model?

Sorry, I forgot to tell you what car. I have a EF XR6. To recap on what i have done so far is, tail shaft ballanced, new uni s, wheel alinment and ballance tyers, new clutch, all under car has been checked over by pedders , with no prob found all bushers and control arms fine. The vibe only happens at that speed 85-95 and the vibe comes from the seat and middle of car not in the stering wheel. Yes, I know my front rotars need replacing but the vibe happens without me touching breaks in or out of gear. All engine and gear box mounts are fine. The car has not been lowerd its all standard. The one thing that has been removed is the harmonic ballancer on tail shaft as it was stuffed. It is made out of rubber, the tail shaft bloke told me as well as ford parts supplier it would not cause that vibe. Its to stop the droning noise coming from tail shaft ,would buy it if somone told me it would stop the vibe $410 wasted if it dosent .....THANKS

bearings tight? In my experience it was the bearings if the brakes arent f**k

i still think it might be wheel balance on the back wheels. Try swapping the fronts to the back. If it is balance the vibration will come from the front (steering) after swapping wheels. This won't cost anything to try and should eliminate one cause if it doesn't fix it.