Hey all,


just curious if anyone else has used the Hypertech Speedometer Calibrator. The place I had my lift put on originally set the tire size to 34.5".... The speedometer showed about 4-5 mph faster than I was actually going.


I recently have reprogrammed it 2-3 times adjusting the tires sizes a tad higher each attempt and have gone up to 36" tires, but my speedometer still shows about 4-5 mph faster.


Any help is appreciated.

 

if your speedo is saying your going faster than you actually are than you went to far. with tire size.

i put 35s on without adjusting the speedo and mine tells me im going 5mph slower than im actually going

 

Yes, so wouldn't making the tire size larger show me going slower?


Or do I need to decrease tire size to go slower?

 

The larger tires you have over stock, the slower your speedometer will show you going compared to your actual speed - you're going further in the same amount of time.

So it seems like you're doing the right thing, if it's not changing your speedo reading regardless of the tire size, maybe the programmer isn't working right?

I'm sure you have the manual: http://www.hypertech-inc.com/Product...calibrator.pdf

How are you determining your actual speed?

 

yes you need to decrease the tire size.

i went from the factory 275-65-18s
to 295-65-20s and im showing 55 on my speedo when im actually going 60.

so if yours is showing faster you need to decrease tire size in the computer

 

From what I've read on prior generation trucks, the Hypertech can be pretty far off on the sizes, so you just have to screw with it until you find a size that matches up.

 

Got it, thank you all for the help. I had to decrease the tire size to 32.50 and now it is dead on!


Thanks all for the replies!

 

not a problem man. glad you got it figured out

 

I did the same tire size and your right put it to 32.5 and your right on. This Hypertech speedometer is awesome... worth the $250 took about 10MIN. Not sure if it locks into your truck like the SuperChips do but I like it.

 

Is the Hypertech the kind of programmer that you only have to plug into the OBD-II port or do you have to connect it to a computer first to download prgram?