PDA

View Full Version : M3Pilot's Tyre Experiment (long)


M3Pilot
06-03-2002, 11:31 AM
For a while now my car has felt somewhat twichy.
But I couldn't put my finger on it as to when it started.
I was thinking that maybe it was my suspension getting past it's best.
I have EDC on my car and this stuff is $$$$$$$$ over here, it works very well but a front strut assembly is about $850 a corner and the rear shock is about $500 a corner.
This doesn't include the springs, and with this set up you can't just replace the insert like with a normal set up you have to buy the whole front leg which is why it's so expensive.
Don't know if you guys ever got it?????

The car really seems to tramline on any uneven surface or follow the tyre mark that are worn into the road by trucks over time.
When the camber on the road changes it tends to really drag the car around.

Some suggested that it was the new tyres that I fitted a while ago.
The car runs Bridgestone SO-3's at the front and Goodyear F1's at the back.

So I thought I would swap the front and back tyres so see how that felt. The car used to run the Goodyears all round and used to feel fine.
So I swapped the tyres, took it for a blast and would you believe it the car felt great , it wasn't being dragged around all over the place.
So the theroy was correct that it was the tyres, maybe they just don't suit the set up of the M3 or what. I don't think it's the pressures as I run the stock settings of 2.2 bar at the front and 2.4 at the back, or about 32F 35B psi.

Or maybe it is my suspension is past it's best not helping out, or the construction of the Bridestone having really stiff side wall or something. The front end grip from the is awesome, but whether I will get them again for my car I don't know.
I might get the brand new Goodyear F1's when the come out.

So let me know what you guys think or if any of you have had simular experiances.

Sorry about the long post :)

M3Pilot
06-03-2002, 01:01 PM
All my suspension is still stock.
But how's your for tramlining?
But once again it's different tyre's to what I am using so I guess it won't have the same affect, and all your suspension is new.

M3Pilot
06-03-2002, 03:02 PM
But does the car tramline as I think were running about the same size tyres?
Mine are 225/45/16.

GR8 Ride
06-03-2002, 03:03 PM
Rob,


What the hell are you doing with 3 degrees of negative camber in the front of your M3, and 4.5 degrees of negative camber in the rear?

Who did the wheel alignment on your car? I seriously doubt Steve or John would actually set your car (a street car) up with such parameters, whether you asked for them or not.

I'd suspect your car is much closer to 2.5 degrees negative camber, and even that is quite a bit. I think John is running only 2.5 degrees negative camber in his....

And while it's a good idea to replace some of the rubber bushings with poly-urethane ones, I highly doubt you've pushed the car hard enough to ever experience flex in the bushings....


Pat

M3Pilot
06-03-2002, 04:16 PM
There must be some other people running SO-3's out there?
Can anyone shed any light on this for me?

SJTrance
06-03-2002, 07:21 PM
I have the SO3's all around on m 98 328 with H&R sports, Bilstien Sports, Eibach Sways, and rear strut bar. Yes, these tires do tramline a bit, but that's to be expected with such a sticky tire. But I love the tire and I totally recommend them to anyone. But I believe that the main problem you're experiencing is that you have two different types of tires on the car. Naturally, this will change everything about how the car handles. Of course, the SO3's were probably sticking better than your Goodyears and it's making the front end (which controls all the turning and such) to act twitchy while the rear end is loose. I'll bet that if you get the S03's all around, you should be good to go.

M3Pilot
06-04-2002, 08:12 AM
Originally posted by SJTrance
I have the SO3's all around on m 98 328 with H&R sports, Bilstien Sports, Eibach Sways, and rear strut bar. Yes, these tires do tramline a bit, but that's to be expected with such a sticky tire. But I love the tire and I totally recommend them to anyone. But I believe that the main problem you're experiencing is that you have two different types of tires on the car. Naturally, this will change everything about how the car handles. Of course, the SO3's were probably sticking better than your Goodyears and it's making the front end (which controls all the turning and such) to act twitchy while the rear end is loose. I'll bet that if you get the S03's all around, you should be good to go.

I think that having to different tyres on doesn't help, as under heavy braking it feel like the back wants to come round.
But If this is the case why does it feel so much better when the goodyears are on the front, It should feel just as bad, but all the tramlining is gone, the car feel much less nervous.
So basically I feel it all down to the SO-3's