strut your stuff

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angoose
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Tue May 28, 2019 4:49 pm

hello all,

Looking to order suspension for my 1988 320i. Want to make sure I order the correct strut size.

I'm aware there were two sizes of strut on the car 45 and 51 mm. On e30zone wiki it says it has 51mm struts is this true of all 320i models?

Can 51mm struts be fitted to cars with 45mm struts originally if it was the case 45mm struts were on the car?

Many thanks
stones
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Tue May 28, 2019 5:45 pm

Quote from wiki:
Struts come in two sizes: 45mm and 51mm. The bigger size was standard on all 323i and 325i models, all Tourings and all Cabriolets. If you are unsure of what size strut your car has, and you can't remember your maths lessons, then use a bit of string. Wrap the string around the strut, and then measure its length; 141mm means a 45mm strut, and 160mm means a 51mm strut.

I think the 45mm has a threaded collar that fits on the outside of the strut and 51mm it screws inside
Yes you can upgrade to the 51mm struts but you will also need springs to suit, but bearings are the same, i'm sure a trader on here can help.
HTH.
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arrisbmw
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Wed May 29, 2019 8:58 am

I read somewhere on other models was hit and miss what diameter struts you have,
on the lower cc usually have 45 mm .
get a pair of calipers , and measure them the diameter , can be done without jacjing the front up , thou does make it easier.
I assume your changing the inserts , inside the strut. if so your need spring compressors and special tool the top nut is difficult to remove,
rix313
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Thu May 30, 2019 12:07 pm

angoose wrote:
Tue May 28, 2019 4:49 pm
hello all,

Looking to order suspension for my 1988 320i. Want to make sure I order the correct strut size.

I'm aware there were two sizes of strut on the car 45 and 51 mm. On e30zone wiki it says it has 51mm struts is this true of all 320i models?

Can 51mm struts be fitted to cars with 45mm struts originally if it was the case 45mm struts were on the car?

Many thanks
You will have 45mm if they are still original.

You can swap to 51mm no problem, just make sure you have the correct 51mm dampers as well.

Everything else is the same.
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HJ1981
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Thu May 30, 2019 12:45 pm

Wouldn't typing in your VIN into BMW ETK/realOEM show what was equipped on your vehicle?
angoose
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Sat Jun 01, 2019 7:54 am

We got it up on the ramp and 51mm after checking. thanks all
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