I thought I'd share some measurements I made of the various common spring lengths. This confirms what I've thought for a long time that Eibach springs lower substantially more (at the front at least) than the spec suggests.
Non-Sport v Sport v Eibach spring lengths
- Thread starter mrscalex
- Start date
Good info Robert
And just to add further to the unexpected results, I have a pair of KYB rear springs which I would expect to be 240mm (ie non-Sport length) and they are 220mm (ie Sport length).
However as per picture below - left to right, KYB, BMW Sport, BMW Non-Sport you can see the KYB spring is somewhat crude in comparison without any tapering. I believe that would make the KYB more linear in behaviour compared to the progressive BMW springs.
However as per picture below - left to right, KYB, BMW Sport, BMW Non-Sport you can see the KYB spring is somewhat crude in comparison without any tapering. I believe that would make the KYB more linear in behaviour compared to the progressive BMW springs.
Another thing to factor in would be the tensile strength of the metal, thicker wound being stiffer and vice versa.
Personally with the Eibach springs I always find the rear lower than I would like. I'm tempted to give a go Eibach front and Sport /Z3M Rear.
Or to level it out with thicker spring pads:
5mm # 33 53 1 136 385
7.5mm # 33 53 1 136 386
9mm # 33 53 1 127 224
10mm # 33 53 1 136 387
14.5mm #33 53 1 094 754
Personally with the Eibach springs I always find the rear lower than I would like. I'm tempted to give a go Eibach front and Sport /Z3M Rear.
Or to level it out with thicker spring pads:
5mm # 33 53 1 136 385
7.5mm # 33 53 1 136 386
9mm # 33 53 1 127 224
10mm # 33 53 1 136 387
14.5mm #33 53 1 094 754
Sure. And I would imagine there's other science to it as well. Not least that I'm not taking into account the fact the springs would be compressed to some degree while mounted so may give slightly lower drops than I've quoted. But the short length of those front springs is just bonkers unless I'm missing something. I was actually thinking the reverse to you with Eibach rears and Sport front but that's based purely on the table rather than experience.
I guess the ultimate test is measuring wheel arch height but it would need to be on the same car for accuracy.
Roy's coupe is on BC Coilovers I used a 8/7kg spring rate and set the height to what I felt worked and 50/50 weight.
Worth noting they have 32 point damper adjustment on each corner.
The rears seem to sit a bit lower than the front with the Eibachs. Daves 2.2 did the same, I've asked him to order some 10mm spring pads to lift her butt up a little
I don't think they are with the build quality you get. £860 all in.
They are known to be a little firm because of the narrow spring, if you want an OEM feel with all that adjustment the KW V3 is the way to go but they're around £1700 so a little steep in price.
Edit: if your referring to spring pads Dave just bought 2 for £6 each.
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Ha,Ha I was talking about the spring pads mate but then you set a seed.
Tony.
Tony.
I like reading this about this stuff but dont always understand it 
Irrespective of which springs are used, am I correct in thinking that the ride height should be the same reading for the front O/S and N/S And again for the rear O/S and N/S.
Mine are all different, so does that mean the springs are probably on their way out.?
Irrespective of which springs are used, am I correct in thinking that the ride height should be the same reading for the front O/S and N/S And again for the rear O/S and N/S.
Mine are all different, so does that mean the springs are probably on their way out.?
Probably means some of them have been replaced with non genuine springs during it's life mate, just like a huge percentage of cars out there on the road.
Tony.
Tony.
Worth noting the makes too if still legible Malc.
Tony.
Tony.
Guys,
What about the pre-load on the standard springs that will reduce the standard spring height when actually fitted to the car?
I’ve never played with fronts but on the rear isn’t some compression of the spring needed to get it in place and the shock bolted back up?
another thing - there is a ratio to be applied on the height of the rear springs to actual ride height because of the pivot point - for example a 10mm spring pad actually adds more than that, I’ve got it posted somewhere when I was tuning the rear height. Will check but I think the ratio was 1.6ish according to the internet.
What about the pre-load on the standard springs that will reduce the standard spring height when actually fitted to the car?
I’ve never played with fronts but on the rear isn’t some compression of the spring needed to get it in place and the shock bolted back up?
another thing - there is a ratio to be applied on the height of the rear springs to actual ride height because of the pivot point - for example a 10mm spring pad actually adds more than that, I’ve got it posted somewhere when I was tuning the rear height. Will check but I think the ratio was 1.6ish according to the internet.
Yes, a bit of a bug bare me, both my zs that have been on eibachs have had the appearance that the rear is lower then the front, problem is that I'd rather lower the front, you can clearly see an arch gap on the front but not on the rearThe rears seem to sit a bit lower than the front with the Eibachs. Daves 2.2 did the same, I've asked him to order some 10mm spring pads to lift her butt up a little
Yes both front and rear are held in some compression. Hence my comment about me not taking that into account. These are bench lengths.
To make a true comparison of on the car impact you'd need to swap springs on the same car with everything else constant and measure to a fixed point. BMW use bottom edge of the wheel rim to underside of the wheel arch I think.
That would make sense as it rules out tyre depth
Robert N
Regular Member
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- Apr 30, 2019
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- 14
I've just bought a set of second hand Bilstein B6 dampers and the fronts came fitted with springs, I wasn't expecting that and had planned to swap my 'Sport' springs onto the Bilsteins.
My question is how do I identify what these springs are? I worked in the spring industry many moons ago and coils like this were identified with coloured stripes to show rates etc, these are so marked but different colours! The front left hand coil has Yellow stripes across 4 of the coils but the right front coil has White spots on 2 of the coils!! So I am confused - any thoughts?
My question is how do I identify what these springs are? I worked in the spring industry many moons ago and coils like this were identified with coloured stripes to show rates etc, these are so marked but different colours! The front left hand coil has Yellow stripes across 4 of the coils but the right front coil has White spots on 2 of the coils!! So I am confused - any thoughts?