New e39 owner Tire

[E5CAP3]

Hey everybody. I just purchased a 1999 540i. The car is going to need new tires, and I need some help since it is running 275's in the rear with 18 inch style 32s. I think this is kind of huge, and want to go with 255's. Would 255/35/18 be the correct size for 18" style 32's? I'll post an introductory thread after I can take some pics

[Flounderasu]

Tire size will depend on the width of the wheel.

[edjack]

Rule of thumb is that the wheel width s/b no less than 90% of the tire cross section for optimal handling. A 9 inch wheel will properly acommodate a 255 tire.

[E5CAP3]

OK, so next stupid question. How do I determine that? I have never had a car with non-stock wheel size, and don't wanna order the wrong ones. The wheels aren't marked are they?

[Flounderasu]

On the inside of the wheel, it should be marked.

[Qsilver7]

OK, so next stupid question. How do I determine that? I have never had a car with non-stock wheel size, and don't wanna order the wrong ones. The wheels aren't marked are they?

You wrote that you have Style 32 Wheels...if that's true, then you don't have non stock wheels. But you do need to determine if you have a staggered set-up (rear wheel is slightly wider than the front).

The 18" Style 32 wheels for the e39 came in 8"x18" (front) & 9"x18" (rear)...as well as 15", 16", & 17" sizes. The BMW recommended tire size for 18" staggered wheels is 235/40/18 (front) & 265/35/18 (rear). If the wheels are all 8"x18"... then you may want to consider 235/40/18 all around.

If you look around the hub of the wheel...if they are original BMW wheels...you should see the wheel's specs (BMW part nbr/offset/etc) If you don't understand what the markings are, take a pic of it and post back...or jot down what the front & rear says and post back


BMW Style 32 Wheel

http://i.imgur.com/m8G7vQ3.jpg

5er E39 7x15 * ET 20
5er E39 M5 7x16 * ET 20
5er E39 M5 8x17 * ET 20
5er E39 Touring, M5 8x17 * front ET 20
5er E39 Touring, M5 9x17 * back ET 26
5er E39 Touring, M5 8x18 * front ET 20
5er E39 Touring, M5 9x18 * back ET 24

[E5CAP3]

Thanks for the responses! I didn't know the style 32's were a stock option on the e39 540i.They are indeed original BMW style 32's. Checked the stamps and they are staggered with 18x9J on the rear. What does the J denote? I think 275's in the rear is overkill, he's got 235's up front. So would the tire size in my original post work? And do most people run 255's or 265 rear?

[John in VA]

Originally,
8x18 ET 20 front - 235/40R18
9x18 ET 24 rear - 265/35R18

[IndiansFan]

The letter that typically sits between the rim width and diameter figures stamped on the wheel, and indicates the physical shape of the wheel where the tire bead meets it.


In the cross-section below, you can see the area highlighted in red.

[E5CAP3]

OK cool, then the J doesn't correspond to tire sizing. I'm gonna trade out for 265 rears since 275 just seems like overkill. What's the typical range you have on tire sizing with these wheels?

[edjack]

OK cool, then the J doesn't correspond to tire sizing. I'm gonna trade out for 265 rears since 275 just seems like overkill. What's the typical range you have on tire sizing with these wheels?

See my post above. Tire Rack also lists proper wheel width for a given tire size.