OK, First off, nothing is really wrong with my truck, but about 2 months ago, I went to the largest tire I could without changing the suspension, 285-75-16. Now this morning while I was running late for work, I was cruising in and doing about 72 when Mr Policeman cruised in behind me. He said I was going 79. Now I know that a larger tire can have the affect of making the speedo show slower than you are really going but that much?

Does anyone know what the difference in speeds would be from the 265-75-15 to the 285's?

Then I see on the ticket that he "paced" me. He was prolly doing 79 to catch up.

UGH!!!

 

Assuming your stock tire is 255/70/16, if you were to go to a 265/75/16 then if your speedo reads 60 mph then your actual speed will be 3.2 mph faster, with 285/75/16 then it will be 5.5 mph faster.

 

Hmmmm Well maybe I was doing 79. Oops. TIme to head to the dealer to get my puter updated then. Damn.

 

hate it when that happens,

 

Yea so do I. But I can still argue this a bit. He claims the road we crossed he "clocked" me on was 55MPH. But tomorrow morning on the way in, I am taking a picture os the sign that says 65MPH BEFORE the road. That should help me a bit.

 

hey guys check this out...i was suprised http://www.miata.net/garage/tirecalc.html

 

Yea...it can throw ya off pretty good. Stock setup on mine is 235's and I'm running 265's. When it says I'm goin 45 its right about 50. When ya get up higher though its worse, when it reads 70 I think its something round 77. My truck (97) is too old to reprogramm comp. I mean there is a way to fix it...but its $200 and all it does if fix the speedo read out. Not worth it to me...unless I start piling up the tickets... *knock on wood*

 

heres a story for you my wife had a subaru bajathat had atire problem where if you were going 55 by the speedo you were only going 50. they could not come up with a fix (subaru). at least Ford can come up with a fix.

Lance

 

Well at least I got him on one thing for the ticket. He wrote on it, Mile post 282 and Hwy6. Well about Mile post 281 and a half, it changes to 65MPH. HA! So I'm gonna get a pic of it . I'll admit I was speeding, but in a 65MPH zone, not 55.

 

Hooah, don't let them get away with a thing. might even get it thrown out.

Lance

 

I got 15mph off a ticket when I told the magistrate I had changed the gears at the speedo was off by 25mph.. (which it was). saved me from getting 91 in a 65..

 

Yea I am gonna take the truck into the dealer and get the puter re-programmed. THen take the work order in so they don't think I am BSing them. May help.