nj07

I have a question will 19 inch wheels throw of my speedometer or would it still work fine I found a sett for $500 with tires and I was hopeing the speedo would not be affected. please let me know thank you.

Jazzer The Cat

Your speedo will only be affected if the overall diameter of the tire differs from stock. It can be easily corrected via hand-held tuner.

My experience has been 1/2" larger/smaller diameter was 5 MPH off at 70 MPH. This happened when I went from the stock 225/60/15"s to 245/40/17"s on my '85 GT Stang quite some time ago. I would be willing to guess that a local tire shoppe can either correct it for you or knows someone who can, possibly Ford dealer.

Jazzer

StillDyl

im pretty sure its a percentage of the speed thats off, not an exact number

Jazzer The Cat

^ correct.......

Otherwise, if your speedo was 5 MPH too fast, it would just hover there when at a stop sign I used 70 MPH as a base because we all can relate to that number and may help avoid a ticket on the highway.

ssv6ponypower

i put 20's on and it threw it off by 7 mph at 80 so it would say 80 but i would be doing 87 and i used my tuner and its right on now

ybnormal

heres a link mustang master posted that will help you http://www.discounttire.com/dtcs/infoTireMath.dos
that will help you with your figures. I went with a 295 x 35 x 19 on the back and it changed my speedometer abot 2 miles over at 60 mph. I also had a gear change and I had to use the sct to set the gears up . I am heading to the shop to get a real calibration done. ticket maybe its off and I can get it reduced a little would help.

I think 19's are a great size there is just not a lot out there and what is is exspensive. I paid over 400 a piece for my back tires.......