The 4-lug 4x100 cars (316i, 318i, 318is, 318ti and the 1.9 Z3) convert to 5-lug 5x120 by swapping the wheel-carrying hubs front and rear plus the rotors. Do it and the whole 5x120 wheel catalogue and the six-cylinder/M3 brakes open up.
Front, you need:
- A pair of 5-lug front wheel hubs from a six-cylinder E36 (325i/328i or M3), pressed into your front knuckles
- Fresh front wheel bearings to press them in with (the six/M3 hub uses a larger bearing)
- 5-lug front rotors — the 286mm vented six-cylinder disc, or the 315mm M3 disc if you're going M3 brakes — with the matching calipers and carriers
Rear, you need:
- 5-lug rear stub-axle hubs (the flanged hub that bolts into the trailing arm) from a six
- 5-lug rear rotors, plus the larger rear calipers if you're upgrading
You keep your knuckles and trailing arms — it's the hubs and rotors that carry the new bolt pattern. Finish with a set of 5x120 wheels, and since the fronts are apart most people fit the bigger 328i/M3 front brakes at the same time.
Two things people miss:
- Press in new wheel bearings while the hubs are out
- Keep the ABS reluctor rings clean so you don't trip the ABS light afterward
Once it's done, wheel choice follows the normal 5x120 offset rules.