Speedometer reading with different size tires
Thread Starter
MBWorld Fanatic!
Joined: Nov 2014
Posts: 4,242
Likes: 628
From: Chicago burbs
2015 S550
Speedometer reading with different size tires
My stock wheels are 8.5 in the front with 255/45/18 and 9.5 in the rears with 275/45/18 tires. I just put snow tires on those wheels at 255/45/18 all around. So the snow tires in the back are .7 inches shorter (2.6%) vs the stock tires.
With the shorter tires in the rear, will my speedo read differently? If the speedo runs off the rear wheels, then I know that it will read about 1.5 mph high at 60 mph and show that I'm putting miles on my car quicker.
I'm looking for some clarification about where the speedo reading is coming from.
With the shorter tires in the rear, will my speedo read differently? If the speedo runs off the rear wheels, then I know that it will read about 1.5 mph high at 60 mph and show that I'm putting miles on my car quicker.
I'm looking for some clarification about where the speedo reading is coming from.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2014
Posts: 4,242
Likes: 628
From: Chicago burbs
2015 S550
Just did some testing. The car speedo matches the GPS on my phone....and the speedo does not shoot higher when I turn off the traction control and spin the tires. So the speedo reading must come from the front wheels.
If anybody has any info to the contrary, I'd like to hear it.
If anybody has any info to the contrary, I'd like to hear it.
