Speedometer Recaliberation

[Boar-Ral]

Hello,

I have read of many people installing larger diameter tires on their trucks but recaliberating the speedometer has only been casually touched upon. (A quick search only found approximately 10 instances, and nothing definitive was said.) Since I installed larger tires, my speedometer is obviously off somewhat. In addition, I wonder if it has any impact on the slippage I am noticing with the front tires which never existed before. (The reason I find this so odd is that the BFGoodrich All-Terrain A/Ts have a more aggressive tread pattern than the factory tires; I would have expected less slippage, not more.)

Unfortunately, I was told that the dealership cannot recaliberate to a tire my size and that I would need to find an aftermarket place to do this. I asked at the store where I had my lift and wheels and tires installed and they told me that they would install a Superlift TruSpeed Signal Calibrator. It is a nice unit, but at $300 CAD or $200 USD, I am wondering if it is overkill. I know that a programmer like the Hypertech will let me recaliberate, but it is a little different. I am just so confused now with these options and am not sure what to do. $300 is steep, but I cannot really justify the $700 CAD for a Hypertech III either. (I wouldn't fiddle with anything else. I wouldn't want my dealership to flip.)

Does anyone have any experience with this or have any advice that I can use? I would appreciate any. Thanks in advance.

 

[gandolphxx]

Hello,

I have read of many people installing larger diameter tires on their trucks but recaliberating the speedometer has only been casually touched upon. ?(A quick search only found approximately 10 instances, and nothing definitive was said.) ?Since I installed larger tires, my speedometer is obviously off somewhat. ?In addition, I wonder if it has any impact on the slippage I am noticing with the front tires which never existed before. ?(The reason I find this so odd is that the BFGoodrich All-Terrain A/Ts have a more aggressive tread pattern than the factory tires; I would have expected less slippage, not more.)

Unfortunately, I was told that the dealership cannot recaliberate to a tire my size and that I would need to find an aftermarket place to do this. ?I asked at the store where I had my lift and wheels and tires installed and they told me that they would install a Superlift TruSpeed Signal Calibrator. ?It is a nice unit, but at $300 CAD or $200 USD, I am wondering if it is overkill. ?I know that a programmer like the Hypertech will let me recaliberate, but it is a little different. ?I am just so confused now with these options and am not sure what to do. ?$300 is steep, but I cannot really justify the $700 CAD for a Hypertech III either. ?(I wouldn't fiddle with anything else. ?I wouldn't want my dealership to flip.)

Does anyone have any experience with this or have any advice that I can use? ?I would appreciate any. ?Thanks in advance.

Check with Jet Performance - they have a new "black box" that goes between the tranny and the control line - adusts for tire/gear sizes - and fakes out the speed limiter - i have seen in Truckin and Truck trends - it is not on their site - just call - it should be about $125 USD.

You really need to recalibrate it - it is affecting your ABS.

 

[the_dude]

The diffrence is soooo slight that it's not worth the money and time to get it fixed. I doubt recalibrating would affect the slipage, that doesn't seem like an issue that could be fixed with it.

Note, this is my opinion, I'd live with the spedo being off a MPH.....

 

[Boar-Ral]

Check with Jet Performance - they have a new "black box" that goes between the tranny and the control line - adusts for tire/gear sizes - and fakes out the speed limiter - i have seen in Truckin and Truck trends - it is not on their site - just call - it should be about $125 USD.

You really need to recalibrate it - it is affecting your ABS.

Thanks for the heads up! I will check it out and see if I can find a deal on it.

Others do not think that one or two miles per hour is reason to fix this, but I personally find the job 'unfinished' if this isn't done. And as you point out, it can be dangerous too.

Thanks again.

 

[Boar-Ral]

The diffrence is soooo slight that it's not worth the money and time to get it fixed. I doubt recalibrating would affect the slipage, that doesn't seem like an issue that could be fixed with it.

Note, this is my opinion, I'd live with the spedo being off a MPH.....

Gandolph says that the ABS can be affected and I seem to recall others mentioning it too. ?Just to be on the safe side, I think I will get it fixed. ?I don't want to give an insurance company any reason to screw me over in an accident. I would also think it would be illegal to have it out of caliberation. And those one or two miles per hour will eventually have a pretty big toll on the odometer too, I would think.

 

[zeeya2000]

Boar-al, i don't know what size tires you put on it, but i went from stock 16" to the stock 17" size which was 1" and it threw my speedo off 4-5 mph by way of using a gps to check it. After resetting it with the HPP3 it is now about 1 off, I don't think any of the speedos are exactly accurate, but gandolphxx is right about the ABS system and also your computer is set up to shift gears by using rpms, your rpms are now different so will be your shift points which will affect some items also.
I think the jet performance would probably be your cheapest route and get the job done.
Just my .02 worth
ZEE-YA