stephens

The Aussie MB web site has detailed specifications and pricing for the new E55. Can't wait until Xmas for my new ride!! There appears to be an optional wheel fitment:
AMG 18" Light Alloy Wheels 5-Spoke (set of 4)
AMG 18" Light Alloy Wheels 5-Spoke (set of 4) F:255/40 R18 R:285/35 R18
Standard: Front: 8 J x 18 H2 ET 30 - 245/40 ZR 18 Rear:9 J x 18 H2 ET 39 - 265/35 R18

E55 KEV

Stephens, go with the optional setup with:

255/40/18 front & 285/35/18 rear. Awesome!

jamesp

could you please enlighten me on the advantages to a staggered setup? how can it help performance that the rear tire is smaller than the front? sorry for the dumb question, but i'm just learning about performance enhancements so i'll ask someone who knows. thanks.

E55 KEV

You mean "how can it help performance tht the rar tire is larger than the front".

I don't know the technical aspects of it. This topic is better suited for the 'Wheels' section. I guess the idea is to stuff the widest tire possible in each wheel well and the rear will accept a much larger tire than the front can. I believe the wider the rear tire (the drive tire) the more traction you can get. More traction equals the more power to the ground and more speed. Something like that.

mikE55

I'm no expert either, but here's a simple explanation. The 285 (width) means the rear wheel is wider vs. the 255 in the front. The 35 (height) indicates that the side wall (profile) is lower/smaller vs the 40 in the front. With all the power and torque in the E55, the wider rear tires provides much better grip, as this a rear wheel drive car. The lower profile also provides for less body roll as the sidewall will flex less. The trade off is a harsher ride. Having narrow tires in the front (relative to the rear, 255 is still very wide) usually helps to make the steering better and reduces understeer.

jamesp

that explains it.

jswedberg

Not true - typically (with no other changes) wider tires on the back will reduce OVERsteer - that is, it will make the car understeer more.

An obvious example is the Porsche 911, which had a big oversteer problem early in its life. Wider rear tires helped to tame the oversteer.

That can all be adjusted, though, with different anti-sway bars, shocks , and springs.

mikE55

Well, you maybe right. But the 911's engine is in the rear, so it's vehicle dynamics are different than an E55's. In the case of the '95 BMW M3, it originally had the same tires all around and had some understeer. BMW later changed to a staggared setup with the '97 M3 to improve the car's handling.

But then again, I'm no expert in this area and will differ to other's engineering wisdom.