speedometer changes with 17" wheels

[Stealth5]

i got some 17" wheels recently with 215/40-17 yokohama avs es-100 and wanted to know if my speedometer is off at all from changing these. it seems like im going 1-3 mph faster than the speedo tells me, but it seems like my revs are lower than they used to be at the same speed in the same gear....whats goin on?

 

[igdrasil]

no, I do have 17 with 205/40/17. 215 is a bit wider, but put them side by side with the 16 and you will know.

 

[mp5user]

Low speedomter and lower revs are consistant. I'm surprised that you noticed a difference though.

Fred

 

[walight01]

at 60, you should read 59.8 according to whalentire.com

 

[Stealth5]

well, the way i tested it was less than scientific, but my friend drove next to me at 40 and i had to go 38 to keep up, and i put my old tires next to my new ones, and the new ones are TAD bigger

 

[mountjonas]

is the difference really big, or could it be tread wear on the old ones.