PeachParts Mercedes-Benz Forum - View Single Post

Tump · #1 07-17-2003, 07:45 PM

Hi all --

I've changed my O.E. wheels and tires to wider AMG wheels and tires and am now wondering how the wheel and tire size difference may affect acceleration and speedometer accuracy.

The specfic changes made are as follows:

--- O.E. 7.5" J x17" AMG Monoblock Aero II's, 17 H2 ET 35 in the front and 8.5"J x 17 H2 ET 30 in the rear with Continental Sport Contact 225 45 ZR 17 (front) and 245 40 ZR 17 (rear) and (2 bump spring pads all around)

were changed to

--- AMG A203 400 1302 17x8.5 ET 34, Style III, Composite 5-Spoke, 2-piece alloy rims with Dunlop Sport FM901 Tires, 235/45ZR17 at all four corners, using 4 bump (17 mm) spring pads in the rear and 5 bump (21 mm) spring pads in front.

The thicker pads were installed to solve the fairly frequent rubbing at the front left wheel that I experienced when going over large bumps and dips in the road. Changing from a 2 inch overall drop to a 1.5 inch overall drop and having Benz perform a 4 wheel alignment to Europoean C43 spec's resulting in -1 deg. 30' and 31' camber in front and -2 deg. 31' and 47' camber at the rear, eliminated the rubbing problem.

Handling has improved dramatically, but because the rear tires are now about 1 inch taller than O.E. would that affect speedometer accuracy much? (if so, by how much?) and would it hamper acceleration times? --- checking with the Police installed public radar speed display and my seat of the pants meter, acceleration and speedometer accuracy seem to be about the same. But, I may not remember accurately how the car felt before the modifications.

I do apologize for my lengthy post but would greatly appreciate any help, knowledge or experience offered.

Thanks