Change in Tire size
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Junior Member
Joined: Nov 2011
Posts: 36
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From: MA
ML350 Bluetech 2012
Change in Tire size
I bit the bullet and purchased 18" wheels and winter tires for my 2012 350ML. I just noticed over the weekend that the speedometer is off by between 5-10% when compared to several GPS devices (phones, Garmin and TomTom). Is there any way to adjust it?
Junior Member
Joined: May 2010
Posts: 32
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From: Mississauga, ON
2012 ML350 BlueTEC; 2003 4Runner V6 Limited
What tire size did you put on? When I was researching for 18" winter tires my choices are 255/55R18 and 235/60R18, both have negligible effect on the speedometer.
But I ended up with 255/50R19 on a different set of 19" wheels.
But I ended up with 255/50R19 on a different set of 19" wheels.
MBWorld Fanatic!
Joined: Jul 2003
Posts: 6,770
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From: Lake Oswego, OR
2020 GLE 450; 2023 BMW M2 Coupe
Speedometer error
255/55-18 Blizzaks run 718 revs/mile; 255/50-19 Pirellis spec at 717 revs/mile, virtually identical. 265/45-20 Pirellis are at 700 revs/mile (2.5% difference). I don't know of any way to adjust the speedometer; in the old days you could get a gear reduction. There may be an electronic solution if you go to a speedo shop, but I doubt it is practical. Did you check the reading with your standard tires?
Thread Starter
Junior Member
Joined: Nov 2011
Posts: 36
Likes: 0
From: MA
ML350 Bluetech 2012
The reading was exact (or better stated within the margin of error) with the factory tires.
As Mercedes sells the ML350 with different tire sizes there must be a way to adjust. The dealer didn't know how to adjust. I figured since everything is electronic it should be an easy adjustment of entering in tire size and the computer does its work.
As Mercedes sells the ML350 with different tire sizes there must be a way to adjust. The dealer didn't know how to adjust. I figured since everything is electronic it should be an easy adjustment of entering in tire size and the computer does its work.
MBWorld Fanatic!
Joined: Jul 2003
Posts: 6,770
Likes: 1,264
From: Lake Oswego, OR
2020 GLE 450; 2023 BMW M2 Coupe
Tire sizes
The reading was exact (or better stated within the margin of error) with the factory tires.
As Mercedes sells the ML350 with different tire sizes there must be a way to adjust. The dealer didn't know how to adjust. I figured since everything is electronic it should be an easy adjustment of entering in tire size and the computer does its work.
As Mercedes sells the ML350 with different tire sizes there must be a way to adjust. The dealer didn't know how to adjust. I figured since everything is electronic it should be an easy adjustment of entering in tire size and the computer does its work.
