To John from Meyle UK. I bet your company doesn't sell the correct road springs for the 2002 Z3 2.2 litre Sport model. They seem to be virtually unobtainable, even from BMW.
Hello Mike (Bumpa),
I’ll come to you first, regarding the Sport version of road springs -10mm, you are quite right these springs are not available anymore, when I was at ZF, we manufactured the shockers front and rear for assembly line fit, however we did not manufacture the road springs. The front and rear shocks for both the standard suspension and the sport version are the exact same size in dimension.
The difference in both front and rear is internal, for those that don’t know inside the shock tube there is a pressure flow valve that controls the flow of oil inside the tube when the piston is compressed or extended, this determines the ride comfort, which is obviously stiffer on the sport version. Another myth is that a gas shock(in this case) is full of gas, ‘wrong’ it is a mix of oil and gas, an easy observation is if it is pure oil the piston will remain static when not under load (not fitted), if it is a gas shock the piston will automatically extend to its max length when not under load, if the gas piston does not extend when not under load, it’s time to change them.
Please note the shock does not have anything to do with ride height it is a ‘shock absorbing damper’ the ride height is governed by the springs. In many cases you can fit Standard shocks to a sport model if the outer tube casing is the same, it will just be less harsh ride comfort.
BACK TO THE SPRINGS, vehicles normally have a 15 year end of life parts availability Where the original manufacturer must keep the parts available for the said vehicle so in the Z3 case the year would be 2017/2018, I have also found that these springs are like hens teeth, ‘non existent’. There are many options of so called sports versions eg Beilsteins but the ride height is NOT the same as the OE spring. I myself have purchased spare second hand springs from a sport model (breaker) in case any of mine snap so I have a ready replacement to fit in the eventuality.
As I previously stated, I do not know the OE spring supplier, however I do know a manufacturer in Holland that make for Mercedes and BRABUS as well as several other OE marques that may manufacture as a set but I do not know what their minimum production run would be, if it was say 50 sets I may be able to get an identical set of springs made? As you can expect I would not be able to check at the moment, however when we get back to some sort of normality I may be able to find out.
I hope this helps...........
