Bad vibration at70 mph mini cooper 51 - Mini BMW Cars & Trucks

Try an owners forum before you call the dealer. My guess is there's a speed control unit problem.

The only way to correctly diagnose what is going on is to have a diagnostic scan done, sounds like the pcm has gone into 'limp home' mode which restricts power to prevent damage to the powertrain

Sounds like the AC compressor bad

STOP........ Take it to your dealer before anything bad happens.

Need more detail.....

This most likely may be due to the new tires... make sure that they are balanced correctly... 1 out of 10 times this will happen and you should only be able to feel it at certain MPH... somtimes worse then others.

I had a similar issue and it ended up being a broken wheel bearing. I even ended up having two, one was broken on my front passenger side, and one broken on my rear driver side. The part costs about $280.00, but could cost around $400.00 with service repair. The noise of a broken wheel bearing can sound like a humming, and over time it becomes louder. The car can be driven with a broken wheel bearing, but doing so can eventually lead to other wheel/tire maintenance. MINI's endure this commonly due to their low profile to the ground. Here is a forum on further issues experienced, including the bearing, and efforts towards recalls. http://newmini.wordpress.com/2009/02/17/mini-cooper-power-steering-failure/#comment-884

I need to replace the transmission in a 2005 mini cooper can I replace the 5 speed with a 6 speed?

have you tried checking the earth conections ,

Change your Minis Mass Air Sensor this will solve your problem.