OEM speedo off?

[ctrlraven]

So last week I was driving around with my friend in the marauder near his house and on his street there was one of those stand up radar speed display units. Well I ended up going past it about 6 or 7 times because I noticed that when the car was saying I was doing 30mph the radar displayed 28mph, did it at 35mph and said I was going 33mph and did it at 25mph and said 23mph and did it at some other speeds. Has anyone else noticed this on theirs? I don't know if its because the low tread amount thats on the rear tires and btw my rear tires are OEM, usaually keep them at 36-37psi and OEM 3.55 gears. I just found this to be really odd and wonder when I get some new 255/55 kdw2's how much more it will be off before I get an xcal2 unit to correct the tire size change. For the mean time I guess this works in my favor because I'm actually going 2mph slower then what I really think I am. :D

[TooManyFords]

My marauder has been 2mph higher even after I switched gears and such. I think Ford has this dialed into all their cars since everyone likes to go "a little" above the speed limit on the highways. I doubt they'd admit to that, but that is my story and I'm sticking to it.

I've used my GPS to confirm speeds and it is always 2mph higher.

But as always, YMMV!

john

[SergntMac]

My #3 MM is just like your's, showing 2 MPH faster on the speedo than I'm actually moving. It's also 2 MPH ahead of the OBDII speedo. OEM tires too.

[2ndMDRebel]

Its a diabolical plot by Ford to get everyone out of warranty faster!

[ctrlraven]

Its a diabolical plot by Ford to get everyone out of warranty faster! For some good reason I would believe that too :lol: