[Dan Kelly]

Hi all,

I have a problem with the rear end of my car breaking away very easily when exiting corners. The rear tyres are relatively new and at the correct pressure. Before anyone says "just slow down a bit" going through the same corners in my E34 at the same speed causes no problems whatsoever.

What should I be checking? There is obviously something wrong and I don't want to crash my lovely car

 

[Bimmerbear]

What kind of tires do you have?

 

[Vector57]

Check out your rear sway bar brackets. They are notorious for breaking.

Regards,
Alan

 

[Dan Kelly]

What kind of tires do you have?

They are Pirelli P6's, not great but not terrible either. They have around 6mm tread.

 

[plenty]

I take it this didn't happen previously? Have you changed something on the car? When mean "exiting corners' you mean power oversteer, right, not the kind you get entering a bend on a trailing throttle? Does the back end go under power even with DSC on?

I have P6 All Seasons winter tyres on the back as well - not brilliant by any means but I am not getting powerslides with DSC on, even in the slippery conditions we've had in the UK all winter.

 

[Dan Kelly]

.

 

[VacMan]

S62 = lots of low end torque compared to the s38.

 

[Dan Kelly]

I take it this didn't happen previously? Have you changed something on the car? When mean "exiting corners' you mean power oversteer, right, not the kind you get entering a bend on a trailing throttle? Does the back end go under power even with DSC on?

I have P6 All Seasons winter tyres on the back as well - not brilliant by any means but I am not getting powerslides with DSC on, even in the slippery conditions we've had in the UK all winter.

I haven't changed anything. Feels like it begins to let go mid corner on a neutral throttle and starts to slide as soon as power is applied even with DSC on. It's not undrviable but it does mean I can't push on if I want to.

Yes the S62 does have a lot more torque than an S38 but this is not the problem.

 

[plenty]

Check the alignment - lots of potholes at this time of year.

 

[Gustav]

Alignment is always good to check.

Check the alignment - lots of potholes at this time of year.

 

[Quicksilv3r]

DSC sounds like it's packed up. :dunno:

 

[E55AMG2]

I haven't changed anything. Feels like it begins to let go mid corner on a neutral throttle and starts to slide as soon as power is applied even with DSC on. It's not undrviable but it does mean I can't push on if I want to.

Yes the S62 does have a lot more torque than an S38 but this is not the problem.

The S38 is a damn sewing machine compared to the S62. If you get on the power too early (which you have to to get any exit speed with the E34 M5) it will step out a bit on you. It should be relatively easy to control. If it's not, you might want to look into your rear toe settings to see if they're too agressively toed in.

 

[Sailor24]

What air pressure are you running front and rear?

 

[Dan Kelly]

2.4 front and 2.6 rear.

I know that the s62 is a very different animal than the s38 but I just don't feel that I can carry anywhere near the same corner speed in the E39 as I can in the E34. I really don't think this is a power/torque issue, more of a general handling problem.

 

[E55AMG2]

Drop your rear tire pressures to 2.4bar. Also, get your alignment checked.

The E39 is deceptively fast...you'll usually be carrying more speed than you think since it's so smooth.

 

[Sailor24]

2.4 front and 2.6 rear.

I know that the s62 is a very different animal than the s38 but I just don't feel that I can carry anywhere near the same corner speed in the E39 as I can in the E34. I really don't think this is a power/torque issue, more of a general handling problem.

I measure in psi over here on this side of the pond, is that bars? No matter I would say try increasing the pressure. If that is bars then that is what I used to run in my E34 m5 maybe I was higher but the balance front to rear was the same. Then I got an E34 540 with the heavier engine and more torque (read less smooth torque) and I had to raise all pressures but even more rear than I ever had. I think I was 36 front and 41 rear for daily drives and up 4 front 4 back for fun weekend drives. E39 is different, we got snow soon after I bought the car so I really don't have good pressures yet, but they are not my E34 pressures for sure. I have seen alot of posts where the guys are running higher front pressures than rear, this baffles me but I will try it. The E34 is not as smooth(not sure that is the right word) as the 39 which maybe what you are feeling. I am always surprised when I look at the speedo and see how fast I am going in the 39. It is faster than it feels coming from 15 years of driving 34s. I am getting used to it.

 

[caspian65]

Where in the turn are you applying throttle? Are you releasing the clutch in the turn? Heel-toe to keep rev's up?

 

[Dan Kelly]

Had the car up on the ramp today and checked everything out. No obvious problems.

I think it may just be a tyre issue, I've been used to PS2's on my E34 and now I've had the E39 for a while I've been gradually getting up to speed in it.

It seems the traction limit of the Pirelli's is much, much lower than the Michelins. I can't believe how easily they break away if its just slightly damp. The extra power/torque of the S62 doesn't help

I'll just have to slow down a bit or buy some new PS2's :grinyes:

 

[Chris_M5]

What is the temp when this is happening? I've noticed that with my Pilot A/S as the temp gets colder they tend to break loose more easily. Can't wait for warmer weather and PS2's back on the ride.

Chris

 

[E55AMG2]

Had the car up on the ramp today and checked everything out. No obvious problems.

I think it may just be a tyre issue, I've been used to PS2's on my E34 and now I've had the E39 for a while I've been gradually getting up to speed in it.

It seems the traction limit of the Pirelli's is much, much lower than the Michelins. I can't believe how easily they break away if its just slightly damp. The extra power/torque of the S62 doesn't help

I'll just have to slow down a bit or buy some new PS2's :grinyes:

I'd agree with you there. The P6 is an all season IIRC, the PS2 is a max performance summer!