What is the largest diameter rim can I put on my 2002 330i sedan without making mods to my car?

19 inch rims with something along the lines of a 235/35r19 (approx) tire. beond that you may have gaurd clearance issues

Used the www.tirerack.com application. It is quite helpful.

I agree with luke on size BUT you will face many issues with larger rims. Loss of comfort, if you dont wanna ruin rims then you cant drift, and speed bumps.

the joy of appearance over function, i would go a 17 inch package personally coz it still looks good but has a decent ride to go with it. find some legit second hand E46 M3 rims. look good and function well for ride comfort

Definitely a form over function question. The larger the rim the rougher the ride and will cause poor gas mileage. However, if you're set on doing 19s are the largest you should consider going. In terms of tires, depends what width and offset you want to run. I'm big fan of staggered sizes and am currently running 19 x 8.5 front and 19x9.5 rear with a 45mm offset. I have 235/40s in the front 265/40s in the rear.

I agree with Luke, the E46 M3 rims, are the best option. 19" just make the ride harder, and the suspension is going to suffer more.

Correct me if I'm wrong, but e46 M3 rims aren't offered in 17".

It depends on what type of style of a rim its is. Because different certified rim designs have different sizes.

Ride quality is everything.performance gains are negligible in traction values..however final gear ratio is incorrect for stability/braking/increased stress on chassis.not advisable.in actual stance ,appearance the car does "look" more potent-- or capable

does anyone know if 19 by 9 will fit with a 51 offset