323CIBOY

I own a 2000 CL500 w/ 20" wheels. I noticed that my car feels "governed" at @ 115 mph, which is kind of wierd - because Mercedes Benz told me that the car was governed at 130 mph. I took the car to the local MB shop & the foreman said ther was nothing wrong with the car, but because of the larger wheels on my car - that's probably the cause for the 115 mph limiter. Has anybody with 20" wheels experienced this???

absent

Larger wheels hurt not only the ride but also the acceleration and confuse the speedometer which has to be re-calibrated.

323CIBOY

How can I get my car recalibrated???

Wehrmacht_benz

i have a 01 cl500 with 20 inch foose speedster wheels...the cars are supposed to be limited at 155mph....i have never got mine above around 125 because theres barely enough room to go fast around here and that is fast enough on public roads or interstate...anyway how would larger wheels mess up the speedometer? my car was just serviced and the only thing was that they had to reset some tire pressure moniter thing to stop coming up due to new wheels being on,,

AMG2GO

Guys the wheel is not the issue, its the overall diameter of the wheel/tire combo. So if you are riding on 20's with rubber bands for tires around those wheels and the overall diameter is the same as stock, you are fine. If you have exceeded stock diameter, you got all kinds of problems, one of them being you have essentialy changed the gear ratio.

If your wheels are larger, that would actually INCREASE your potential top speed before the ECU steps in. So the tech needs to do a quick calculation in his head before he tells you what he is saying. Smaller diameter means more rotation, and the speedo thinking you are going faster.

If you have an aftermarket wheel/tire combo, you need to go into COMAND, hit the service button, and follow the menu. Somewhere in there is a thing that asks what your tire sizes are front and rear, and it recalculates the speedo settings.

The problems that come with 20" wheels other than this are many, and I have written on them before. So I won't waste time doing it again.

raymond g-

taken literally, i think the terms are loosey in the 2nd paragraph, but your first I agree with. here is a neat calculator to help regarding rotation.

323CIBOY

Ok - last week I sent my ECU out to Speedtuningusa in Maryland to get a little more Hp/torque out of my CL500. When I received the ECU back, didn't notice alot of difference in car's performance low-end, but noticed a little quicker acceleration in the higher-end and that pesky governor-issue @ 115mph was taken care of. I was able to get my car up to @ 125mph and slowed down. As far as my speedo being off - it's not off by that much because I was driving down the freeway along my friends CL500 (on stock wheels) @ 70mph. When he was doing 70mph, my car was at @ 74mph. Not a big difference at all. So, for now, governor issue has been resolved.