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[Rewted]

Do larger wheels/rims offer a performance advantage, or is it strictly aesthetics?

eg: Default 17" or upgrade to 18-19"

[stooken]

From my understanding, yes.

I don't see how the larger wheels increase performance, especially since most of them are heavier.

[Rewted]

Was just thinking with more circumference, you may get a lil more performance.

[S4to335]

I dont go to a larger wheel unless it is lighter than the wheel I am moving from. :-)

Turn in is usually slightly better with a lower profile tire (going from 18 to 19") There are advantages and disadvantages..that is for sure.

[S4to335]

Originally Posted by tyrewt

Was just thinking with more circumference, you may get a lil more performance.

You do not want to change the circumference...that is what a proper plus 1 or plus 2 conversion is for...increasing the wheel size but decreasing the tire height proportionally.

[Rewted]

Oh ok... so it scales to proportion. So if I were to upgrade from the stock 17", to say an 18"... the rim would get larger, but the tire would be smaller. Correct?

Basically just about looks.

[STE92VE]

I'm not an automotive engineer, but larger wheel sizes will effect handling characteristics of a vehicle. On the same vehicle, larger wheels require a lower sidewall height of the tires which will result in better handling under dry, smooth road conditions.

These tires are known as performance tires and give a harsher ride than tires with a larger sidewall. As per BMW, they should not be driven in the snow.

[The Cleaner]

The short answer is Yes. Anything over an 18 is getting close to diminished returns, 20+ is for posing not performance. There is no performance gain after 18-19.

[dxb335d]

in racing terms its to fit larger diameter brakes on course and for road them really for asthetics but also come in handy in you want some serious stoppage fitted behind them :rocks:

[Chi-town330]

shorter sidewall tires handle turns better, as there is less of a moment arm (distance) from the point of normal force (pavement) to the point of attachment (where tire meets rim). But given the 17" rims on the 3 series come with a fairly low 45 AR tire to begin with (unlike some other car brands), I think only a small % of folks on here really push the car to the point that the difference is FELT. that's just my opinion.

18" rims with lower AR tires look GREAT, give a small gain in cornering (discussed above), might give a VERY small loss in acceleration depending on the rim (even if rim is same weight, the weight is further out, so moment of inertia is increased, requiring more energy to rotate), and will feel slightly rougher on bumpy pavement. Also, potholes can more easily damage a rim with very low AR tire (have had it happen), the tires are more expensive to replace, and it is VERY easy to do cosmetic curb damage to 18's.

Also, given you live in Canada - 18's are usually wider, and come with summer performance rubber. The handling capability falls noticibly in cold weather due to the type of rubber and how it reacts to cold, and they are USELESS and VERY DANGEROUS on ANY snow and ice. anybody who tells you otherwise is full of crap. so if you do get them, and live in snow country, most folks HIGHLY suggest you get a second set of rims/tires for the winter.

reason I don't have 18's on my current car (have had them before, love them) is because I have a condo in the city and don't feel like trying to store a second set of rims/tires, the ride is not smooth on crappy city streets, and valet parkers kept dinging up my rims.

hope this helps. I am really not a tire expert, so many folks on here will know much more.

EDIT: ok, over 2 months after I orginally posted this, I put on 18's......they just look too damn good......

[kabhatti]

If I can ask a question, regarding bigger rims, I'd like to go to 18 inch 162's. Any opinions of sticking with the 225-40-18 Kumho all around, not staggering?

[S4to335]

225/40/18 all around will look funny in the back if you dont do a spacer to move it out a bit.

[kabhatti]

Originally Posted by S4to335

225/40/18 all around will look funny in the back if you dont do a spacer to move it out a bit.

What size spacer? Your AW is what I want my AW to look like.

[Rewted]

Originally Posted by Chi-town330

shorter sidewall tires handle turns better, as there is less of a moment arm (distance) from the point of normal force (pavement) to the point of attachment (where tire meets rim). But given the 17" rims on the 3 series come with a fairly low 45 AR tire to begin with (unlike some other car brands), I think only a small % of folks on here really push the car to the point that the difference is FELT. that's just my opinion.

18" rims with lower AR tires look GREAT, give a small gain in cornering (discussed above), might give a VERY small loss in acceleration depending on the rim (even if rim is same weight, the weight is further out, so moment of inertia is increased, requiring more energy to rotate), and will feel slightly rougher on bumpy pavement. Also, potholes can more easily damage a rim with very low AR tire (have had it happen), the tires are more expensive to replace, and it is VERY easy to do cosmetic curb damage to 18's.

Also, given you live in Canada - 18's are usually wider, and come with summer performance rubber. The handling capability falls noticibly in cold weather due to the type of rubber and how it reacts to cold, and they are USELESS and VERY DANGEROUS on ANY snow and ice. anybody who tells you otherwise is full of crap. so if you do get them, and live in snow country, most folks HIGHLY suggest you get a second set of rims/tires for the winter.

reason I don't have 18's on my current car (have had them before, love them) is because I have a condo in the city and don't feel like trying to store a second set of rims/tires, the ride is not smooth on crappy city streets, and valet parkers kept dinging up my rims.

hope this helps. I am really not a tire expert, so many folks on here will know much more.

Very informative, thanks. I'll be sticking with the stock 17".

[dxb335d]

stock 19" on my one

[Chi-town330]

Originally Posted by Chi-town330

shorter sidewall tires handle turns better, as there is less of a moment arm (distance) from the point of normal force (pavement) to the point of attachment (where tire meets rim).

actually, I wasn't very clear, didn't really finish my thought here. given there is a shorter "arm", then for the same force (i.e., same speed around a turn, same g force on car), the lower AR tire will flex out to the side less, and therefore will handle better.

Also, people tend to put WIDER tires on 18's, so not only do you have lower sidewall height, but larger footprint. Force = pressure * area, so the wider the tire footprint, the better the traction. THIS is where the real performance gain is, I would think. My first post was more related to the physics of equal width tires, but just changing the diameter of rim and AR of tire. The reality is almost everybody puts wider tires on the bigger rims (the 18 rims themselves are usually .5" wider, are better set up for wider tires). I figured I better add this before I get flamed . And like I said in my first post, I am not Joe Tire Guy or Joe Racer Guy.....

[BrunoT]

I put 18's on the E90, up from 16's, and it was a noticeable difference in grip and somewhat in terms of feel in turns. But going from runflats to non runflats could be much of that, as well as going from 195? to 235mm width on the tire. The penalty is somewhat more road rumble and you feel more bumps. Still pretty smooth for a car that handles well. 17" is probably the best overall compromise. I just didnt' see any affordable styles I liked in that size at the time. I did it because of looks as well as performance. And I will point out that width for me is probably more important than height of a wheel. I like the wider stance. Not that I love huge wheels, but some cars are DESIGNED to look good with certain wheels. Proportions are such are subjective, but to me it looked the best, and I did NOT want to buy a set of 17" and not be satisfied.



I went from 17" to 18" and back to 17" on a Saab 9-3 SS with the same type and width tire and the 17's ride a little softer and still perform well. The 18's looked better and the car is not ever going to be "quiet" like a BMW, regardless of tire size. Lots of rumble from the road coming up from the wheels relative to the BMW.

The funny thing is, the BMW is superior technically in almost every area, but I enjoy driving the Saab more. I can take turns smoother and with more confidence at high speed, for whatever reason. I just took it for a spin and I just feel more comfortable and confident with it, even though there is obviously less steering feedback, and the engine/driveline isn't as smooth. It isn't as solid feeling, has a few rattles. Not sure why exactly. The Saab drops like a rock in resale value and isn't as reliable, though.

[sblument]

yeah Chitown330, my teeth are chattering on Halsted down to the Target every weekend...

[e92man]

the wideness of the tiire makes a big difference