I'm new to this forum. I'm from Malaysia and drive a year 2000 S280. I am facing the exact problems. THere's a vibration coming from the car around 60-70mph. It feels more like the whole car vibrates and is not isolated to the steering only. It disappears above 70mph.
Unfortuantely i'm not very well versed with the technical aspects so some terms used might be wrong. The initial diagnoses:
1. Tyre problem (balancing) - been thru 3 diff sets (Nankangs, Bridgestone SO3s, Conti CSC2). Problem still persists. Have had tyres balanced countless times by various renowned tyre workshops here. No discernible imperfections with tyres.
2. Rim Problem - I'm currently on Brabus 18" rims. Borrowed a friend's 17" OEM S Class rims but problem still persists.
3. Drive shaft bearing issue - they're all fine.
4. Long/Prop shaft problem: A brand new prop shaft costs around USD 3-4k here. It's kinda a very expensive test to see if that's a problem.
Any thoughts or inputs in this matter would be much appreciated.