16 inch wheels to 18 inch wheels

hello, I have a 2003 bmw 325xi and I wanted to put some 18 inch wheels on it. I was curious on how to go about buying tires for the rims that i already purchased. I previously had 205/55/r16 on my bmw, I am upgrading to an 18" wheel 18x8 5x120mm ET20 . I was wondering if anyone could answer what tire size I would need to make a smooth ride with my new wheels.

thanks!

Originally Posted by Droz23

hello, I have a 2003 bmw 325xi and I wanted to put some 18 inch wheels on it. I was curious on how to go about buying tires for the rims that i already purchased. I previously had 205/55/r16 on my bmw, I am upgrading to an 18" wheel 18x8 5x120mm ET20 . I was wondering if anyone could answer what tire size I would need to make a smooth ride with my new wheels.

thanks!

Unfortunately, you made a classic noob mistake. You bought those wheels *before* asking here....which if you did, we all would have told you that they`re not compatible with an E46 fitment. The offset is all wrong, and is likely for an E39 (5-Series), which would mean that the hub centerbore is too big as well.
There is no way to fix this, the most logical path would be to sell those "new" wheels, and start all over again....better informed next time (let`s hope).

Fast Bob is correct. He is a long time member of this forum and knows whatever he types here for responses. There maybe a select few individuals who have been able to fit an ET20 wheel on their E46 but they would have gone with a ton of fitment modification to the body of the vehicle. Lots of time, calculated risk, and down time to make it happen. Even then it's still wouldn't be a smooth/comfy daily drivable vehicle.

Thank you both very much,

It's not a big deal yet because I bought them from a friend for really cheap so I can resell.

So I know I may sound like a noob, but exactly what Wheel size and tire size combination will I need to fit on my e46? I want to be sure I get the correct size.

Thanks!

A decent good looking offset for the front should be ET35. The rear if you want it flush then you'd keep it ET35 as well but you make need to have less square looking sidewalls and a bit more stretched to fit that aggressive rear ET35 fitment. A safe way to go that a lot of guys go with is ET45 for the rear. This all depends on how low your suspension will be. I have ET45 in my rear sedan and with 265/30/19 mounted on a 9.5" wheel. The tire is slightly too wide for my driver side as I rub the top corner of the tire against the wheel well at my ride height. If it was just a tad higher I wouldn't have a problem. I never rubbed with 255 tires installed. With an ET40 rear I'd need 245 or even 235. But ET35 is perfect for the front!

Generally, offsets (aka/"ET" or "IS") between 35 and 50 will work fine on the E46. A staggered setup (wider wheels in the rear) looks good, but reduces your options for rotating tires.
Also, the brand & model of tire can make a considerable difference when figuring potential clearance problems....some are substantially larger (overall size) than others, even though they may be the "same" designated size.
It`s always best to err on the slightly conservative side.

Educate yourself, read the E46 Wiki....

Thanks a lot guys,

one more question. I am talking to someone who wants to sell some 18 inch lorenzo wheels. they are 5/120 bolt pattern. They are also 18 by 8 in the front and 18 by 10 in the back. Will this fit my e46 bmw 325xi? It is all stock and has never had lowering/raising of body.

Thanks!

Originally Posted by Droz23

Thanks a lot guys,

one more question. I am talking to someone who wants to sell some 18 inch lorenzo wheels. they are 5/120 bolt pattern. They are also 18 by 8 in the front and 18 by 10 in the back. Will this fit my e46 bmw 325xi? It is all stock and has never had lowering/raising of body.

Thanks!

Bolt pattern (5 x 120) is only one of the THREE critical fitting specs. The other two are OFFSET, and HUB CENTERBORE. You need to know what these terms mean, and how they affect your particular wheel fitment situation before even considering any wheel purchase. Start studying....

And yes, trying to stuff ten-inch wide wheels on the back of an E46 is guaranteed to cause problems. Stick to a more sane choice, like 8.5 inches....

10" is pretty hardcore on a non ///M.

The safest thing you can do is buy some wheels from one of the board sponsors. I bought the E9x ///M3 replicas from ModBargains.com (who has a WIDE selection of wheels and I HIGHLY recommend doing business with them) that are made for non-///M cars. 18x8 in the front, 18x9 in the rear. Offset: ET40 front and rear. I have 225/40/18 front and 245/40/18 rear for tires. They fit perfectly.