[NAB]

My car has recently picked up the classic 45-55 front end vibration. The car is driven no more than once a week so I strongly suspect the tires are developing flat spots.

One radical solution - which I wonder if anyone has tried - would be to jack up the front of the car when not being used (obviously not a remedy for a daily driver) so that there is no weight on those front tires when not being driven.

I wonder if it would damage the front suspension to have the wheels "hanging" for a long period of time ? I know on W111 and W113 models it was never adviseable to let the wheels hang free.

All the best.

NAB

 

[NAB]

From this forum it would seem that the chassis vibration issue predominantly affects early cars. If so, does anyone know what changes were made to the front end suspension set up in the later cars which effectively made the problem go away ? I can't imagine the car got any lighter, so the tyre flat spots should have still been a problem if that was (at least one) cause on the earlier cars ?

Thanks

 

[NAB]

I've had this problem - with the car's significant weight it is inevitable that flat spots will appear on the tires if the car is parked up for any length of time. Especially the front tires. Apparently flat spotting is more likely on wider tires - and the W140's 235 width was a significant increase on previous Mercedes models. The problem is not unique to W140s - lots of other car and even motorbike forums have raised this issue.

Three practical suggestions (which have worked for me):

1) pumping up tires to 50+ psi will reduce flat spotting - most manufacturers do this between manufacture and delivery. Obviously reduce the pressure before driving;

2) a fast run - say 80mph + for several miles will heat up the the tires and encourage them to reform into a true circle;

3) some companies sell thick rubber matting which they argue minimises the flat spotting when the car is parked up. I have yet to try this but it may be worth a go. The weight of the car will more easily absorbed by the rubber than it will be by concrete. This should reduce the deformation of the cars' tires.

Happy New Year !

 

[NAB]

Bullshit or not, I think you'll find tyre flat-spotting is well recognised as a fact by most experts. I agree it depends on the car and the tyre in question - I also run a 7.5 tonne truck that doesn't get flat spots when it sits for several weeks. I think its a question of the make and model of tyre and the air pressure - most vehicles with a weight above 3.5 tonnes run tyre pressures of 60-100 psi. Commercial tyres will have much thicker tread and sidewalls. The rubber used will be a thicker, less "sticky" consistency and hence less likely to deform under pressure.

I'm not claiming to know the answers, but only reporting what works for me.