The original E21 320i and 323i wheels were 13×5.5″ with an 18mm offset (ET). There were two optional “BBS style” wheels for special editions: a 13×5.5″ ET18 and a 13×6.0″ ET13. These sizes are slightly larger than what was used on the 2002 models. It’s interesting that BMW did not give the 323i a wider wheel.
Other critical wheel specs to know: 4x100mm (3.93 inch) bolt pattern, 57.1mm center bore, 60• tapered bolt seat, and 12×1.5 bolt threads. These are all the same specs as the 2002 and E30. See below for a longer list of similar applications.
It’s very common to upgrade in size but if you wish to maintain an OEM appearance you can use wheel spacers. Since the critical hub dimensions are the same same as an E30, any spacer from those cars will work. Just make sure you also get longer wheel bolts! A 15mm or 20mm spacer would work nicely on original 13″ wheels.
Tuners at the time jumped all the way to 15″ wheels for their upgrades. Alpina used a 15×6.0 or 15×7.0, both with a ET12 offset. BBS and Mahle offered a 14×6.0 ET13 wheel. Another period-correct wheel is the Melber, using the same specs as Alaina. These specs place the wheel 18-25mm further outboard than the factory 13″ wheels. And they do look impressive!
E30 325i wheels are almost a direct fit. They are a good size and the right bolt pattern but a higher offset which causes the inner rim to contact the tie rod. The problem seems to be worse with 15″ wheels as the wheel rim sits where the tie rod is. Big spacers will be required. Even then the tire width has to be narrow so the sidewall does not sit too far beyond the rim.
E30 factory wheel specs:
BBS Style 5, “Basketweave” – 14×6.5 ET30
BBS Style 5, “Euro Basketweave” – 15×7.0 ET24
Here are some other common 4×100 wheels. Remember that as your width gets wider the offset must get lower. Any E30 wheel is likely going to need a spacer.
Alpina “Kopi” – 15×6.5 ET20
BBS Type RA 15×7.0 ET25 (this seems to be the most common E30 size)
Ronal LS – 15×7.5 ET25
My Own E21
I’m on my third set of 13″ wheels on my own 323i. I started with the original 13″ factory “Alpina” style and then 13″ Motorsport 320is wheels. In early 2019 I did a cosmetic restoration on a set of 13×6.0″ VIAL wheels (click for link). I think they look fantastic even in the tiny 13″ diameter. I will be on the hunt for 14″ or 15″ to raise the ride height on these slammed H&R springs.
I recently bought a set of Borbet Type C wheels. These are among my all time favorite wheels. The first race car I ever worked on was a E21 323i with these wheels so it’s funny how things come “full circle”. But I have a problem. The size is 15×7 ET35. I think these were originally a VW wheel. I’m going to need large spacers to make up the difference. I’m thinking 20-25mm. But my 13″ tires are brand-new so it will be awhile before I get them mounted.
Other 4×100 Fitments
Wheels from other cars may also fit. The E21 4×100 bolt pattern (3.93″) was common for other makes too. It’s not the only dimension to consider but it’s a start. You will also need to confirm Center Bore and Offset. A good indicator is FWD or RWD. FWD cars have a high offset to clear the axle shaft. As noted above, the E21 likes a really low offset. Here are other cars that use a 4×100 bolt pattern (list found on the Web):
Acura – Integra to ’89
Audi – most models to ’89, Fox
BMW 1600, 2002, E30 318i/325e/325i
Chevy – Chevette ’76-’87, Spectrum, Nova ’80-’89
Dodge – Omni, Rampage, Aries, 024 ’79-’85. Charger, Daytona (FWD) ’82-’89
Honda – all (except ’76-’80 Accord, Civic) to ’89
Isuzu – Impulse, I-Mark to ’89
Nissan – Pulsar, Sentra ’87-’89
Plymouth – Horizon, TC3, Reliant, Voyager ’78-’89
Renault – all to ’89
Toyota – Celica, MR2, Tercel ’86-’89
VW – Dasher, Fox, Jetta, Rabbit, Scirocco to ’89
Have something to contribute? Let me know in the comments section below.