Front Strut Diameter Measuring?

[Paulsimon8]

I've been looking at replacing the standard Boge dampers on the M3 parts with new items.

However, After looking round, there is some confusion over the front strut diameter.

Some kits say 45mm, and some say 51mm - Having got the digital caliper out today, the front legs on my kingpins are 51mm on the M3 parts, and 45mm on the 320i parts that are on the car at the moment.

I measured the front legs on the main shaft body just below the suspenion cup - is this the correct place to measure them?

[Brianmoooore]

Thats correct.
325, touring, iS and M3 stuff is 51mm, all other saloon stuff is 45mm.

[billgatese30]

what about cabs, or do they just follow the saloon rules (i.e. all 45 other than the 325)

[Paulsimon8]

Excellent

So i'd be worthwhile investing in a H&R Cup kit - altho having sampled this particular setup on Chip's E30 just before he binned it at the Ring, I was extremely impressed to say the least

[fuzzy]

ive just replaced mine with bilsteins from the zone shop last weekend and it gives it a comfy but firm ride,much better than the teeth rattling ride from the old spax set up

[Paulsimon8]

Nice

I've ordered the H&R 60/40 cup kit - as soon as that is here, I can get on with bolting all the running gear on


also, forgot to ask, does the H&R kit come with new caps that secure the insert in the legs?

[eamo]

this is a bit difficult to explain but another way of telling if you have 45mm struts or 51mm is the following.

jack up the front of the car. push up the dust cover on the shock to expose the shock.you should now be able to see the shock valve. At the bottom of the valve where it enters the strut you will notice one of the following - a thin metal collar around the strut or thick gold colored collar.

If its the thin metal collar you have 45mm strut. If you have a thick gold collar its a 51mm strut.

hope that helps.