Ride height spec for E92 M3 zcp ?

[Rajmun340]

I decided to measure the ride height on my stock E92 M3 ZCP (measured from the wheel rim lowest point to the fender arch). I found it to be half a centimeter higher than spec in the front and over a full centimeter higher in the rears !!

Could other members with stock suspensions E92 ZCP compare with theirs ? car must be on a flat surface (in your garage), no street measurements.

spec front (ZCP) : 613 mm ( ~ 24" 2/16 )
spec rear ( ZCP) : 597 mm ( ~ 23" 1/2 )

Those spec values are from an old thread, not sure if it is valid. If you don't have ZCP you should be 1 centimeter above those specs.

measured front (ZCP) : 618 mm ( ~ 24" 5/16 )
measured rear (ZCP): 608 mm ( ~ 23" 15/16 )

My car is a ZCP (i ordered it myself) but my rears seem exactly non-ZCP height spec ? Dealer replaced four shocks recently and i don't have measurements prior the change which is why i am concerned. I did check the shock absorbers Part no and they are correct for EDC + zcp. Coils are the factory stock.

[Richbot]

What are the spring codes? Should be a tag on the front springs and a printed code on the rear springs, beginning with an X. For instance, many ZCP cars are X7 front, X5 or X6 rear whereas most non-ZCP cars are X1 front, X2 rear. If your car is lightly optioned relative to a car with the same spring codes but more (heavier) options, it'll sit a bit higher. If you have spring codes that are associated with ZCP cars, then you're good to go and should stop worrying.

[Rajmun340]

Originally Posted by Richbot

What are the spring codes? Should be a tag on the front springs and a printed code on the rear springs, beginning with an X. For instance, many ZCP cars are X7 front, X5 or X6 rear whereas most non-ZCP cars are X1 front, X2 rear. If your car is lightly optioned relative to a car with the same spring codes but more (heavier) options, it'll sit a bit higher. If you have spring codes that are associated with ZCP cars, then you're good to go and should stop worrying.

Thank you Richbot, I'll try to read the tags on the springs. I suppose car has to be lifted up to see it but i'll try.

I found the TIS pages for that spec (non zcp), it is the value previously referenced indeed. It says tolerance for height is "+/- 10 mm in normal position and +/- 2mm in design position". Any ideas what that means ? My rears value are +11mm off spec. So it would be out of tolerance

[Rajmun340]

Originally Posted by Richbot

What are the spring codes? Should be a tag on the front springs and a printed code on the rear springs, beginning with an X. For instance, many ZCP cars are X7 front, X5 or X6 rear whereas most non-ZCP cars are X1 front, X2 rear. If your car is lightly optioned relative to a car with the same spring codes but more (heavier) options, it'll sit a bit higher. If you have spring codes that are associated with ZCP cars, then you're good to go and should stop worrying.

I read an X6 tag on the front spring. I can see the rears even better but there's no tag on either one and no markings (could only see one side of them). By printed code do you mean stamped on the metal ? But they're painted black. The rears is what i'm worried about since they're +11 mm above ZCP spec. I'll take a picture of them.

[Rat3d ///M]

You're worried that your car sits a whole half a centimeter higher than what the manufacturer says it's supposed to?

[Rajmun340]

Originally Posted by Rat3d ///M

You're worried that your car sits a whole half a centimeter higher than what the manufacturer says it's supposed to?

No, not a half centimeter, 11 millimeter, that's over one centimeter. ZCP cars suspensions should be 1 centimeter lower than non ZCP (different springs) by specification, yet my ZCP measures like std height at the rear.

Yes i am worried it might affect how the front tires wear out given that my factory tires (first set) showed abnormal wear. If they put std springs instead of zcp, you bet i will make them eat them.

[roastbeef]

that amount of height isn't going to have a significant impact on tire wear. it is likely an alignment issue. what did the wear look like on your tires?

[Rajmun340]

Originally Posted by roastbeef

that amount of height isn't going to have a significant impact on tire wear. it is likely an alignment issue. what did the wear look like on your tires?

It looked like severe heel-and-toe wear of thread blocks on the inside of the front tires which usually comes from toe out misalignment. But having the rear higher than it should on a rear drive car also will tend to want to spread out the front toe.

[roastbeef]

Originally Posted by JoeM3SSII

It looked like severe heel-and-toe wear in the thread blocks on the inside of the front tires which usually come from toe out misalignment. But having the rear higher than it should on a rear drive car also will tend to want to spread out the front toe.

As others have stated, a couple of millimeters isn't going to make a difference. Your car probably sags a millimeter or two wit a full tank of gas and/or when driving with a passenger. I think you may be overthinking it and just have an alignment issue.

[Richbot]

The wrong springs won't cause the car to eat tires. Poor alignment might. These springs are all very close in spring rate. The ZCP springs, which I have on my car, do sometimes "lower" the car by more in the front in the rear relative to non-ZCP. I know this because despite adding about 1/4" to the stack height of my front strut/spring setup with the Dinan camber plates, when I added ZCP springs the rear was lowered about 6mm and the front ~9mm. That means if I hadn't added the Dinan plates, my car would have been lowered nearly 16mm up front. Now, some of that is because the upper spring pads on my factory X2 rear springs were smashed whereas the new spring pads were not smashed, but still, about a year later, front is still "lowered more" than the rear.

And it sits 1mm outside of tolerance. 1. that could be explained by a difference in measuring tapes

So relax. And check the spring codes. No you don't need to pull the wheels or jack the car up. Yes you do have to use a flashlight and get dirty, and you might have to lay on your back to see them

Also wtf is heel-and-toe wear? Is that like the smooth spots on all of my right nomex shoes?

Did they align the car when they replaced the dampers? Why were they replaced?

[Rajmun340]

Originally Posted by Richbot

The wrong springs won't cause the car to eat tires. Poor alignment might. These springs are all very close in spring rate. The ZCP springs, which I have on my car, do sometimes "lower" the car by more in the front in the rear relative to non-ZCP. I know this because despite adding about 1/4" to the stack height of my front strut/spring setup with the Dinan camber plates, when I added ZCP springs the rear was lowered about 6mm and the front ~9mm. That means if I hadn't added the Dinan plates, my car would have been lowered nearly 16mm up front. Now, some of that is because the upper spring pads on my factory X2 rear springs were smashed whereas the new spring pads were not smashed, but still, about a year later, front is still "lowered more" than the rear.

And it sits 1mm outside of tolerance. 1. that could be explained by a difference in measuring tapes

So relax. And check the spring codes. No you don't need to pull the wheels or jack the car up. Yes you do have to use a flashlight and get dirty, and you might have to lay on your back to see them

Also wtf is heel-and-toe wear? Is that like the smooth spots on all of my right nomex shoes?

Did they align the car when they replaced the dampers? Why were they replaced?

Ok, i got it this time. The rears are X5 and the front X6. So it's more or less what you said. Bigger number means shorter spring ?
1/3 full tank of gas. Heated seat delete, other than that the car is fully optioned + CF roof. Some people might get confused with millimeters, but it's 7/16 of an inch (half an inch) higher than it should be for zcp spec.

You're right my front are closer to spec (lower).
You are saying your upper spring pad were smashed on your rears non-zcp so you didn't get as much lowering when you replaced them with zcp springs and new spring pad. It sounds like smashed cup lowers the ride. But mine are too high.

Yes heel and toe tire damage, the thread blocks look like bumps in the inside shoulder, i have a separate thread for it. That is usually toe out misalignment. The tires were replaced and i went to the dealer for an alignment along with other work. But they provided no alignment report and ignored my emails when i asked for one. The alignment was a goodwill so i cannot complaint. Maybe they don't have the staff to do more than a rough alignement, then i'll go to an Indy shop.

Shocks were replaced in an attempt to fix ZCP EDC under factory warranty.

[Richbot]

EDIT: Just read your threads on your EDC issues etc. What a cluster.

The spec is +-10mm, which means your car is 1mm out of tolerance, by your measuring stick. Or 9mm, if you use the +-2mm "design" spec on that sheet. Also, half an inch is 12.7 mm.

Whether or not the rear is higher than normal, getting the front to zero toe should be enough to mitigate tire wear. But be warned, our cars (and every BMW I've owned, this one is number 5 of 6) with zero toe still eat inside fronts a bit faster than the outside, because on a ZCP car you're carrying around 1.3-1.4 degrees of negative camber and every time you turn the wheel you're scrubbing the inside tread blocks against the pavement because of BMW's subobtimal econo-car front suspension designs. How long did it take the fronts to get to the point you needed to change them in terms of mileage? EDIT: Just saw your tire wear thread. 18k miles to get to the point where it was bad enough to change them. I've had some degree of the uneven inner tread block wear since my car rolled off the lot new 88000 miles ago. It's not innacurate at all to say that M3's eat tires faster than a car that has little camber, little dynamic camber, etc. Even our box-stock E90 335xi would wear the fronts like this if you didn't rotate, and our box-stock F34 does the same but again, you can rotate tires.

[Rajmun340]

Originally Posted by Richbot

EDIT: Just read your threads on your EDC issues etc. What a cluster.

The spec is +-10mm, which means your car is 1mm out of tolerance, by your measuring stick. Or 9mm, if you use the +-2mm "design" spec on that sheet. Also, half an inch is 12.7 mm.

Whether or not the rear is higher than normal, getting the front to zero toe should be enough to mitigate tire wear. But be warned, our cars (and every BMW I've owned, this one is number 5 of 6) with zero toe still eat inside fronts a bit faster than the outside, because on a ZCP car you're carrying around 1.3-1.4 degrees of negative camber and every time you turn the wheel you're scrubbing the inside tread blocks against the pavement because of BMW's subobtimal econo-car front suspension designs. How long did it take the fronts to get to the point you needed to change them in terms of mileage? EDIT: Just saw your tire wear thread. 18k miles to get to the point where it was bad enough to change them. I've had some degree of the uneven inner tread block wear since my car rolled off the lot new 88000 miles ago. It's not innacurate at all to say that M3's eat tires faster than a car that has little camber, little dynamic camber, etc. Even our box-stock E90 335xi would wear the fronts like this if you didn't rotate, and our box-stock F34 does the same but again, you can rotate tires.

If i had zero issues with my car i would not care about ride height. The main reason i checked ride height is the EDC issue. i know the tires mileage was where some other people put enough 'normal' wear to change them but mine had tons of meat left. They had to be sacrificed due to the heal and toe bumps as ride became noisy as f. Hopefully it won't repeat with alignment (not dealer alignement since they provided no report).

It's been a very tough road to try to fix the EDC issue, if you think that thread is a cluster, multiply by twenty. I actually gave up updating it months ago. The dealer has ordered the module to be replaced at this point. I was thinking that since the four corners ride height determines weight distribution of the car that it can affect edc results. Too high a rear will put more weight on the front axle, front springs will get more compressed giving a different dynamic response. ZCP EDC damping is tuned together with the springs. There are 4 different front shock absorber parts: non-zcp non edc cars, edc non zcp cars, non edc zcp car and edc zcp cars. When one spec if off somewhere it can affect other systems. I wouldn't think ~+1/2 inch rear height matters too much, although it fails spec and should be noted for that.

EDIT: Marginally failing specs seems "good enough" for BMW Motorsport. I think the disparity from one M3 to the next shows some serious quality control issues. I don't mean just ride height but other measurable hard specs too. The variability from one car to the next is just crazy, no surprise some of them explode and others last. I wonder how much of that is them lowering the bar to let every car they produce go to retail with disdain for those M3 buyers unlucky in the draw.

[Rajmun340]

**********

**********



*********




*********




*********




*********



*********