[Ocshark]

Does anyone know the best tire and wheel spec to put on a M340i 2021? Looking for some rims

[marco000]

Depends on your need I suppose?

I guess if you're asking the question, you usage might be mostly street and rare track day use (or not).

Just my personal opinion, I would go close to stock setup (19'')
F: 225/40/R19 R: 255/35/R19

or maybe one or two size up like
235/40/R19 245/40/R19 for front
265/35/R19 275/35/R19 for rear

In terms of rim, you need 5*112 bolt pattern.

stock rim size is
front: 19 * 8J, 27ET (offset)
rear: 19 * 8.5J, 40ET

So looking for slightly wider rim if you're going for wider tires
front: 19 * 8.5(or 9) offset could be something close to stock
rear: 19 * 9 (or 9.5)

Some rims I looked up for:
BBS CI-R, BBS CH-R (around 650 each wheel)
ESR RF-2 (around 350 each)
Vossen HF-5 (600 each)

There are also expensive forged wheels from BBS and VOLK for over 1000 each.