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Recalibrating the speedo for bigger tires?

1644 Views 11 Replies 9 Participants Last post by  RckyMntnKng
Ok so I went to a 35" on the truck....and now Im off by 13.6% on the speedo.

I see alot of topics on using a "Tru-speed" to correct the speedo, odomoter, shift points, abs function etc. These run about 200 bucks....

I called the Dodge dealer and they said they could correct for tire size for $80, and would take an hour.
I a$$ume that just hook up the programmer???

Is there any reason I should not go for the cheaper route?

99 2500 V10 4x4
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i tried this and the dealer said that the computer could only go up to 285's. i thought this was a little ridiculous and unbelieveable but i just left and got a truspeed. now i can switch back and forth b/w my 29's and 35's and just flip a switch to change the speedo.
I have a tru-speed that I took off of my 99 I am selling. I have the box and instructions. I would sell it for $150 shipped to your door.
yea this is how i did it last night since i have 38's its a little diff. drive next to a friend and start yelling back and forth how fast am i going. you'll get if figured out!
You might have a Dealer tech that actually knows how to change it, if so that route is cheaper if you are planning on sticking with that size tire for a while.

If you plan on going bigger or smaller anytime soon, then the Truespeed will be cheaper in the long run.

It has 2 settings for two different sizes, if you have a daily driver size, then an offroad size, or a summer size and a winter size, just flip the switch and instant speedomoter correction.

Otherwise you have to keep going back to the Dealership and changing it, $80 bucks a pop starts adding up.


phox
hypertech? mine takes care of tire size changes.
On 2005-11-24 13:22, hieneken49 wrote:
hypertech? mine takes care of tire size changes.

thats what I use.
with the hypertech do you just tell it what size tires you have and then it tells the truck computer? or do you have to give a ratio or percentage?
just pick the tire size u have, cant remeber what it goes up to but its pretty big.
there's a hypertech for the 98's in the stuff for sale forum
On 2005-11-24 08:02, bradmo42 wrote:
yea this is how i did it last night since i have 38's its a little diff. drive next to a friend and start yelling back and forth how fast am i going. you'll get if figured out!
Yea! Us ******* Texan's can do that!
Would like a truspeed in the future, but I went ahead and got the tech at Dodge dealer to do it for $80.

I tested it out on the interstate with the mileage markers and seems to be correct. So apparently it can be done on a 99 2500 V10
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