1986 baur 325i Wheel Offset question

[Avinit4]

Hello people.... Hopefully a simple question for someone in the know that has 1st hand experience of this?

Its my understanding the offset on standard factory alloys is ET 35,

Can ET 42 alloys be fitted?
What negative effect, if any, can or will this have?

If this is a big NO NO do I have to wait untill I find alloys with the same ET 35 or can I get close to it?

Any tips suggestions to circumvent this issue appreciated... Cheers People

[harry_p]

It depends a bit on the width, standard 7x15 bbs are et 25.

It is likely, that unless very narrow, an et42 wheel will sit a long way inboard and most likely rub the front strut.

[Avinit4]

Not sure I follow you.... I read on a guide that BMW E30 is 4x100 ET35 as in the 4x100 is 4 stud bolts PCD (pitch circle diameter the diameter on the stud hole) and ET 35 is Offset of 35

My current alloys that I have no idea of offset size, have 215cm wide tyres and the alloys im looking at with 42 offset are fitted with 205 cm wide tyres so my current tyres are wider.

Really I'm hoping theres someone on here thats had direct personal experience of this so knows exactly whats what, surely I'm not the first to want to find this out?

Are you saying that my ET 35 is wrong?

[gromgsxr]

ET42 should sit further in the well i believe but using spacers should cure it 8mm spacer should make the et42 wheels to a et34. i think et35 is the max y0ou can go on a e30

[Avinit4]

OK thanks. Its starting to make sence. How wrong was I thinking this was going to be easy to find!..lol.. I took off one of my current alloys to discover they are ET 1/5 that totally threw me, the forward slash in the middle must mean something and cant be 15 surely?

I then dug out original alloys (prefacelft ones) to have a look for ET on them, but par for the course there wasnt one. On the face side of the wheel around where the center cap clips in theres an e35 ? I just keep digging the whole deeper.. such is life

Thanks for your input, appreciated

[Avinit4]

Derrrr Why didnt I wiki it to start with... Its all starting to make sence now

[harry_p]

It depends on the width of the wheel because the offset is the measurement from the centre of the wheel to the mounting face that attaches to the hub.

For two wheels of the same width, A higher offset means the mounting face is closer to the front of the wheel, so more of the wheel will sit further inside the arches, and closer to the suspension components like the front damper strut. It you had a 6in et35 and fitted a 6in et45, the new wheel would sit 10mm closer to the centre of the car.

On the other hand, if you had a 6in et 35 wheel, and fitted a 9in et35 wheel, then the centre line if the wheels would be the same, but the wider wheel would have 1.5 inches on the inboard side + 1.5 inches extra on the outside edge.

Standard e30 wheels,

Steel wheel, 5.5in x14in et35
Alloy bottle top 6 x14 et35
14in bbs 6.5 x14 et30
15in bbs 7x 15 et 24

Ideally you want the widths and offsets to be as close to those as possible. Go much higher and you may run into issues with the tyre touching suspension components on the inside edge.

[Avinit4]

OK thanks... My originals were Bottletops 14" 6J et 35 and current ones are 17" x 7.0JJ ET 1/5

One minute I think I sussed it and then it all falls apart in my head...lol..