I am installing a 1" larger size tire on my truck... if I dont get a reflash right away will my truck be reading more or less miles then actual???

I am installing 33s on my truck tonight and leaving for a trip. I had an appointment at 1pm today to get the truck reflashed but I cant get my tires till 5pm…. My dealer said he cant reflash for the new tire size unless the new tires are on it!!! Is this true??? Is don’t think so but im not sure. He said didn’t we discuss this on the phone… NO you didn’t morons.

Am I going to be racking up more miles on the odometer then real??? My dealer also said not to put the tires on without a reflash cause it would trip the check engine light… well needless to say this is the last time I am ever walking through the doors of this dealer again….. that’s their third strike… scr*w them!!!!!!!!

 

Putting bigger tires on your truck would put on less miles. Your speedometer will also be off. I don't think you will get any check engine lights. This dealer doesn't sound like the kind I would go to. My brother has got a 99 Ram that came with 30" tires. He put 33" tires on it and it hasn't given him any problems. His speed and odometer are off though. I would just get the flash done first then go get the tires put on if it were me.

 

if its less miles then i really dont care... sinc emy engine was replaced at 1352 miles..... So my odometer is not true to engine miles anyways... but I dont want to be putting more miles on the odometer then actual. The whole reason i got my new tires and wheels is for this trip... first time my father will see my new POS truck..... But the tire supplier first screwed me (they forgot to ship the tires out) and now my dealer is a retard (but i already knew that ) and therefore will never ever return to this dealer as long as i live!

 

Bad dealer aside, (and I do know a couple of REALLY bad ones)
I do believe that it's against federal law to change the odometer to not record the actual miles. Doesn't mean you can't run around with the 1'' inch taller tires, but if the dealer did it, they could be fined/jailed.
Not defending them, you know them, I don't.
Still not lawful.
Good luck with your new tires,
Chris

 

im not asking to change the odometer reading on my truck.... Im going on a 3000 mile round trip and wanted my truck odometer to record actual milage and correct speed, reason i wanted the computer reflashed to match the new tires.... But if my odometer is going to read under milage them not that worried... if it would read over milage then that would suck.... but whatever.. i dont freakin care anymore. This truck could explode and id be a happy camper

 

Your ODO will say fewer miles traveled and your SPEDO will say slower speed than you are actually going, I'm guessing less than 10% with the tire size change you are doing. For Simplicity lets say 10%; so at 20 = 22, but at 70 = 77. Don't get a ticket!

 

i just did one of those online tire calculators and it said 4%. Im going to grab my buddys handheld gps just for the heck of it and my V1 has not let me down yet.... but a straight drive from CT to FL... my foot will be in it, thats for sure

 

Yep, 4% sounds about right. Those hand held units are not going to be spot on accurate. I've got a hand held Magellan and it says that my truck is off by 2 mph, but the odometer is dead on.

 

I can answer that question because I just had mine done at the dealer. I went from a 235/ 75/17 to a 265/70/17 and my speedo was slow by 2.54 miles an hour. the dealer put the tire change in his computer while it was on the truck and set it for the new tire size now all is well.

 

04 f150 Screw XLT w/255/70/17 off the lot ...

Speedo read 78 when I was actually doing 75 that's just about 4% off. But wait! ... the OD was off the other way by about -3% ... I discovered this on a 10 mile freeway section that has markers every mile just for this sort of thing, even instructions on signs of how to calculate! Had a hard time with my numbers as they didn't match up speedo vs OD ... so had to try that section a couple more times once with cruise set to speedo 60mph and the next cruise at 60 based on GPS 60mph!

I used both my GPS and a stop watch and the GPS very closely matched the numbers on paper. So, in my experience, that comment that GPS's weren't accurate I beg to differ! Just about any GPS with a 4 or more satellite signal will be more accurate with speed than you can read with any analog speedo I’ve ever seen. As for distance it is somewhat of a different story. There it depends on the frequency of the tracking settings, what type of terrain is traveled etc... Most are quite accurate over an average longer than a couple minutes on a regular freeway type drive!

Truck is a bit different now w/4.56 R&P's, 285's etc... but the percentages between the speedo and OD differences are still the same. I chose to have my speedo to be right smack dab on the money when I calibrated the gear change.

 

I'd have to agree with tycreek, I too installed new tires about 1" larger and my Speedometer is Very accurate on the GPS, radar signs set up at construction sites, and the Ohio State Highway patrol when I got my ticket. (I had the cruise set on 78 and I got Clocked at 78) D'oh!