Vibration Through Car

[Ghost_Dog 0]

I have a 1997 728i getting a vibration 80km to 95kms have done a wheel balance wheel alignment. Started after I changed tyres but do not think it is that. Is the drive shafts balanced?, and if I was to test the drive shaft for movement should it be tight?

Cheers

[Guest FrantiC]

Check the CSB, Flex disc and diff mounts.

[*Glenn* 854]

If you dont have standard wheels on the car, it may need new hubcentric rings, or the tyre guys may have left one off. Strange it only happened after the tyres were done

[QuickSilver 0]

Directional tires on the right sides? I've had them put on wrong and it sent vibration through the car as well.

Edited December 2, 2008 by QuickSilver

[Ghost_Dog 0]

Check the CSB, Flex disc and diff mounts.

How much movement/play in the CSB have been told this but the mechanic that did the last warrant said he checked it an there was slight movement. Which he though was ok.

[Ghost_Dog 0]

Directional tires on the right sides? I've had them put on wrong and it sent vibration through the car as well.

Na they are all good

Cheers

[Guest FrantiC]

Rotational movement is alright, There is usually some slack in the driveshaft. But the driveshaft shouldn't move too much up-down or side to side. Look at the rubber around the CSB, If it is torn at all or worn out it lets the CSB sag down or not support the driveshaft well when rotating.

Or the flexdisc (rubber mount between driveshaft flange and gearbox output flange), If that is torn or the ryuber is worn, that will also cause a vibration.

You are best to replace both IMO..

[Ghost_Dog 0]

If you dont have standard wheels on the car, it may need new hubcentric rings, or the tyre guys may have left one off. Strange it only happened after the tyres were done

The original wheels were 235,60,16

The tyres that I changed were 245,50,17 pirelli on BMW Alloy Spider look and I put on 235,45,17. I am changing the tyres next week to see if it is this set.

Will ask about th Hubcentric rings

Cheers

[Ghost_Dog 0]

Rotational movement is alright, There is usually some slack in the driveshaft. But the driveshaft shouldn't move too much up-down or side to side. Look at the rubber around the CSB, If it is torn at all or worn out it lets the CSB sag down or not support the driveshaft well when rotating.

Or the flexdisc (rubber mount between driveshaft flange and gearbox output flange), If that is torn or the ryuber is worn, that will also cause a vibration.

You are best to replace both IMO..

Cheers

Expalined it a lot better I will check that next week when I put it up on the hoist before tyre change.

GD

[zenetti 0]

The original wheels were 235,60,16

The tyres that I changed were 245,50,17 pirelli on BMW Alloy Spider look and I put on 235,45,17. I am changing the tyres next week to see if it is this set.

Will ask about th Hubcentric rings

Cheers

Why did you put on much lower profile tyres? Not only are you putting your speedo out but will potentially affect the ABS and gearbox.

[martyyn 2]

The original wheels were 235,60,16

The tyres that I changed were 245,50,17 pirelli on BMW Alloy Spider look and I put on 235,45,17. I am changing the tyres next week to see if it is this set.

Will ask about th Hubcentric rings

Cheers

Have you got a photo of the wheels. Ive never heard of 245/50/17 on a 7.

Are the wheels originally off an e39? That would explain a lot and would guarantee that you would need the hubcentric rings.

235/45/17 would be fine on the front of an e32, but I dont know about an e38

[oldskool 4]

Had a e38 730 which had same setup on it when I purchased it, speedo was out by 10 Km/h at 100 Km/h was reading 110 Km/h, put it onto 18's & it certainly felt slower off the mark & less zippy, quite noticable given the overall smallish effect on gearing. Didnt effect abs tho.

As everyone has said could be hubcentric rings or maybe propshaft dounut, sets up a vibe when it is on the way out.

[Ghost_Dog 0]

Why did you put on much lower profile tyres? Not only are you putting your speedo out but will potentially affect the ABS and gearbox.

I was told that a new set was 1k+ each and the ones put on would be about 5 km/h less.

Edited December 4, 2008 by Ghost_Dog

[Ghost_Dog 0]

Have you got a photo of the wheels. Ive never heard of 245/50/17 on a 7.

Are the wheels originally off an e39? That would explain a lot and would guarantee that you would need the hubcentric rings.

235/45/17 would be fine on the front of an e32, but I dont know about an e38

I will post a photo tomorrow, I tried to find a pic on google but not close enough. Only 16' and 18s for this model according to the tyre and wheel tag.

[Ghost_Dog 0]

Had a e38 730 which had same setup on it when I purchased it, speedo was out by 10 Km/h at 100 Km/h was reading 110 Km/h, put it onto 18's & it certainly felt slower off the mark & less zippy, quite noticable given the overall smallish effect on gearing. Didnt effect abs tho.

As everyone has said could be hubcentric rings or maybe propshaft dounut, sets up a vibe when it is on the way out.

What your saying is maybe I should move to 18"?

[mtk540 3]

This has also been a problem with some E39s, noticeable at around 70-90kmh and under braking

Try replacing the front thrust arm bushes.

Other BS members have tried that and it solved the problem

[Ghost_Dog 0]

Hey Guys,

Glenn, Quicksilver, Frantic, zenetti, penry, oldskool, mtk540,

Problem sorted new tyres, no hubcentric rings, so put them in, car runs good now and a pleasure to drive.

Shot Guys

Thanks for your help, will keep on this forum glad I found it.

GD

[*Glenn* 854]

Hey Guys,

Glenn, Quicksilver, Frantic, zenetti, penry, oldskool, mtk540,

Problem sorted new tyres, no hubcentric rings, so put them in, car runs good now and a pleasure to drive.

Shot Guys

Thanks for your help, will keep on this forum glad I found it.

GD

I gather from this that it was the hubcentric rings missing ?

Great to see its sorted now for you