Unsettled handling on E46 M3 Convertible

[Martin W]

I've had my E46 M3 Convertible now for about 8 weeks and I'm not totally happy with the handling. I have just had the geometry checked and it was a little out on all corners and the rear toe was way out so everything has now been adjusted so that it is back within required parameters. Everything is tight underneath the car and everything is where it should be. If I drive enthusiastically around town and country, the road grip is fantastic but it doesn't feel quite 'right' around a sweeping bend on a motorway. In addition to that if I'm just cruising at 30 to 40 and I drive over a manhole for example the car (predominantly the rear I think) squirms. It's not like it's going to throw me off the road or indeed anywhere close to that but I'm sure it's not quite 'right' (there's that scientific term again)! I am running the 19"'s with 'M3' Continentals on the front with about 3 to 4 mill of tread and Goodyear F1 Eagles on the back. The F1's were newly fitted when I purchased the car in November.

Any thoughts would be much appreciated.

Cheers!

[gizlaroc]

Martin W said:

I am running the 19"'s with 'M3' Continentals on the front with about 3 to 4 mill of tread and Goodyear F1 Eagles on the back.

That's your problem.

This has been done do death, mixed tyres on the M3 does exactly what you are describing.

I would put a pair of F1's on the front, it will feel rock solid.

[Pork]

How old is the car and what sort of mileage does it have?

The first thing that jumps out at me is that the car doesn’t have matching fronts and rears. While I don’t think it would make the car drive terribly in isolation, I think it would make a difference on something like the M3..

The other thing to remember is you’re running 19’s and it’s a cab. I run my cab on 19’s and am conscious of it tram lining on motorways and occasionally it felling a little twitchy (I’m going to get the tracking done which should help). Oddly enough, it feels more stable when pressing on.

[dan101smith]

...and check the rear trailing arm bushes and rear springs. Both are weak points.

[Martin W]

gizlaroc said:

Martin W said:

I am running the 19"'s with 'M3' Continentals on the front with about 3 to 4 mill of tread and Goodyear F1 Eagles on the back.

That's your problem.

This has been done do death, mixed tyres on the M3 does exactly what you are describing.

I would put a pair of F1's on the front, it will feel rock solid.

I did a search on this before and then spoke to the local BMW dealership about this very point. They assured me that would have absolutely no negative effect whatsoever. Truth is I'm more inclined to take the opinion of people who drive these cars day in day out opposed to the dealerships test pilots; just looking for a final opinion before I part with more hard earned cash that I haven't got I guess!

[Martin W]

dan101smith said:

...and check the rear trailing arm bushes and rear springs. Both are weak points.

Bushes and springs nice and solid, no clunking or rattling at all.

[Martin W]

Pork said:

How old is the car and what sort of mileage does it have?

The first thing that jumps out at me is that the car doesn’t have matching fronts and rears. While I don’t think it would make the car drive terribly in isolation, I think it would make a difference on something like the M3..

The other thing to remember is you’re running 19’s and it’s a cab. I run my cab on 19’s and am conscious of it tram lining on motorways and occasionally it felling a little twitchy (I’m going to get the tracking done which should help). Oddly enough, it feels more stable when pressing on.

The car is an '03 plate with 46k on the clock. I seldom get tram lining and the car certainly doesn't drive badly, it just gets a bit twitchy from time to time which means I don't have full confidence in it.

Strangely enough, my car also feels more stable when driving enthusiastically in country lanes than it does when pootling around town.

[Martin W]

Goodyear don't do the F1 Eagles in 225/40/19 so it looks like I'm going to have to change all 4 if I want to ensure stability.

Just had a quote of £940 fitted for 2 x 225/40/19 and 2 x 255/35/19 Michelin PS2's.

Sound like a pretty good deal but I could do without this right now.

Credit crunch?..... What credit crunch?!

[puncturewound]

Would the same be said for E36 M3 Evo regarding the none matching front and rear tyres as i have been experiencing the same type of handling?

[gizlaroc]

Martin W said:

gizlaroc said:

Martin W said:

I am running the 19"'s with 'M3' Continentals on the front with about 3 to 4 mill of tread and Goodyear F1 Eagles on the back.

That's your problem.

This has been done do death, mixed tyres on the M3 does exactly what you are describing.

I would put a pair of F1's on the front, it will feel rock solid.

I did a search on this before and then spoke to the local BMW dealership about this very point. They assured me that would have absolutely no negative effect whatsoever. Truth is I'm more inclined to take the opinion of people who drive these cars day in day out opposed to the dealerships test pilots; just looking for a final opinion before I part with more hard earned cash that I haven't got I guess!

When I got my CSL I had the same symptoms, I had the alignment done, then the rear trailing arm bushes replaced, and then the rear springs replaced.

I went into my local dealer to see if anything else could be the cause and they were at a loss. However, one of their techs races these cars and he said he would take it out.
We went down the dual and came off at the first roundabout, with 100 meters of coming off and one corner he pulled over and said "you've got mismatched tyres on."
I swore that I didn't, they were Pilot Sports front and back and all nearly new.
However on looking closer the fronts were PS1's and the rears were PS2's.

I swapped over for a set of F1's that I had from my last car that I never put on and it was back to being a well planted car again.



I picked up another M3 last summer, once again it had Pirellis on the rear and Kuhmo KU31's on the front, the car was a twitchy mess.
Swapped for PS2's all round and it feels like it should again.


The M3 does not like mixed tyres, some brands mixed may be OK, some brands mixed are verging on lethal.

Get them swapped and your car will be sorted.

There are threads and threads about this on bmwland.co.uk where people will not have it that the handling is shot because of miing tyres, after spending hundreds trying everything else they come back and say "in the end I swapped the tyres and it is now sorted."


If it still feels wobbly then it will be the rear trailing arm bushes, but you want matching tyres anyway so do that first.

[gizlaroc]

puncturewound said:

Would the same be said for E36 M3 Evo regarding the none matching front and rear tyres as i have been experiencing the same type of handling?

Yeah, all BMWs are the same, but as you get more power you notice it more.

[Martin W]

Set of Michelin PS2's ordered and should be fitted this Saturday.

I'll let you know how it feels - thanks very much to everyone for your help.

[puncturewound]

happy days ill be ordering a new set of fronts

[gizlaroc]

Martin W said:

Goodyear don't do the F1 Eagles in 225/40/19 so it looks like I'm going to have to change all 4 if I want to ensure stability.

Just had a quote of £940 fitted for 2 x 225/40/19 and 2 x 255/35/19 Michelin PS2's.

Sound like a pretty good deal but I could do without this right now.

Credit crunch?..... What credit crunch?!

You need 235/40/19 if you go with the F1's. 10mm width makes no difference anyway and the F1 is a narrowish tyre.

I run 235/40/19 on the PS2's and 265/35/19 rears.

[gizlaroc]

PS2's are expensive at the moment. But I think they are well worth it.

I have just gone back to them on both cars, I love 'em!

Khumo 31's are a very good tyre and can be had in the M3 sizes for under £500 fitted all round.

[Martin W]

mikez328 said:

gizlaroc said:

Martin W said:

Goodyear don't do the F1 Eagles in 225/40/19 so it looks like I'm going to have to change all 4 if I want to ensure stability.

Just had a quote of £940 fitted for 2 x 225/40/19 and 2 x 255/35/19 Michelin PS2's.

Sound like a pretty good deal but I could do without this right now.

Credit crunch?..... What credit crunch?!

You need 235/40/19 if you go with the F1's. 10mm width makes no difference anyway and the F1 is a narrowish tyre.

I run 235/40/19 on the PS2's and 265/35/19 rears.

Interesting. 2 years ago I owned the 2003 AC Schnitzer British Motorshow car. When I bought it, it had Michelin Pilots - 235/35 x 19 front & 235/30 x 19 rear. The car ran lovely. Then I changed the rears to 265/30 x 19 on a whim & spent the next 9 months until I sold the car tramlining all over the place. The car became a nightmare to drive on country roads.

By the way, at £900+ you are being ripped off - £500 is nearer the mark for 4 tyres delivered (fitment at your own cost). Try harder - or try this link: http://stores.ebay.co.uk/MAILORDERMOTORSPORT-01524... and be shocked at the money you've just wasted......

Edited by mikez328 on Thursday 22 January 16:22

Edited by mikez328 on Thursday 22 January 16:24

I am aware that I can get 4 tyres for less than £500 but if they're not the ones I want then that is a waste and a false economy. The fact is that I'm not going to be happy sticking 330bhp through a set of Nankangs whereas I will be happy to do that with the Michelins.

[MrOnTheRopes]

Martin W said:

dan101smith said:

...and check the rear trailing arm bushes and rear springs. Both are weak points.

Bushes and springs nice and solid, no clunking or rattling at all.

RTAB won't clunk or rattle, you need to take them out to inspect them.
You may not get an audible clue to a broken spring either, unless the broken bit is still in there. Make sure you visually inspect them carefully as it's common to lose the top or bottom (smallest) 'coils'.

[Martin W]

It was a culmination of a number of things in the end.....

Firstly, average handling was improved by full laser geometry set up. Then it was improved significantly further by replacing the RTAB's as both were split although this was not noticable from a visual inspection. Much, much better but still subject to a random twitch here and there so I have finally replaced my mis-matched tyres for PS2's all round.

The car is now absolutely fantastic; a joy to drive and totally planted.

Thanks very much for everyones advice, it is much appreciated.

[M3stann]

I have p zero Nero's on the front and p zero's on the back...
The both perlli but different tread pattern.. Is this ok?
Because of the front wheel size you have to get nero's as the dealer told me I bought it from. True??

[gizlaroc]

M3stann said:

I have p zero Nero's on the front and p zero's on the back...
The both perlli but different tread pattern.. Is this ok?
Because of the front wheel size you have to get nero's as the dealer told me I bought it from. True??

I don't know, some mixed tyres make the car a really twitchy mess, where as some others seem pretty good.