will my bigger tires screw up my speedo?

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Speedo Problems

I just bought new tires that were 60 series instead of 55 series. THis threw off my speedo a few mph, according to my magellan sport track map GPS.
nothing major though. the Speedo reads a few mph slower than actual speed. 1-2mph off at 55 2-3 at 70mph.

If the overall tire height changes at all it will throw it off,
bergs said:
i had 245/45 r17's stock now i have on nitto 275/40 r 17's. they are taller by about an inch, will this **** up my speedo?
Where did you get this figure of an inch taller???
Those 2 tires are the exact same height. Go to tirerack.com pick a 245/45/17 and go to specs.. you will see they are both about 25.7" diameter.