What size struts is mine? 45mm or 51mm?

[Rubes]

hello all, if anyone can help me? i tried searching before doing this...

i'm going to do a coilover suspensions setup, but in order to do that... i would need to know what size are my strut. i'm not sure how to measure this and i dont have that special measuring stick (example tool bottom picutre) that can tell me what size are my front strut.

anyways,

my car is 1987 325E coupe. maybe that can help?

[Holland]

51mm. 45mm are 85 and earlier.

[Thehemiman]

51mm. 45mm are 85 and earlier.

What he said.

[spike68]

What size struts ARE mine?

I'm what they call the grammar police.

[MattAvino]

That tool is called a caliper.

[flyboyx]

my 88 cabrio had a smaller diameter strut housings. i had to replace them with a set from a later model e30 so i could use the bilsteins i purchased for the car.

[reelizmpro]

Obviously u didn't search enough. There are tons of threads just like this.

[jeffnhiscars]

my 88 cabrio had a smaller diameter strut housings. i had to replace them with a set from a later model e30 so i could use the bilsteins i purchased for the car.

Those, oddly enough, must have been swapped in by a PO.

[bmwguy325is]

That tool is called a caliper.

Dial Caliper to be exact thanks.

[reelizmpro]

Those, oddly enough, must have been swapped in by a PO.

Agreed. Only 84-85 318i and some 86-87 base model 325. No 325i came with smaller struts.

[Rubes]

thanks guys!

[reelizmpro]

These cars are now coming up on 30 years old. Things change so the safest bet is to measure your tubes with a caliper to be sure. Flyboy's 88 vert should have came with 51mm struts...not 45mm.

[jeffnhiscars]

You dont have to actually measure them. The 45mm housing has an outside thread whereas the 51's have an inside thread. The gland nuts are totally different.

[Hellabad]

You dont have to actually measure them. The 45mm housing has an outside thread whereas the 51's have an inside thread. The gland nuts are totally different.

Some of the 45mm are inside threaded too. Not sure which ones. This trick works well:

[Rubes]

lol perfect! ^^^^^ thanks!