I just put my 35x12.5x17 tires on and calibrated my speedo with my SC3865 and my speedo is registering 4km/hr above what my gps is showing. What way do I have to go on my tire size on the SC3865? Do I put in a smaller size tire or a larger? Anyone have any advice?

 

Are you sure that your gps isnt slightly off??

 

Measure your tire height. Not the advertised height, the actual height from the ground to the top of the tire as mounted on the truck.

 

Im not sure which way really and Im not trying to be mean but by the time someone comes along and answers this, you could have went out there already and did a "quick adjust" and been done with it......LOL

 

I had to go out of town the next day for work. I didn't really have time do change tunes and test it. I just figured someone may have encountered this problem

I ended up measuring the tire from top to bottom in the center of the wheel and the measurement was exactly what I put in the tuner. I have no idea why the speedo is reading incorrectly. Any ideas?

 

well it came today but i'm too busy and with the weather i won't notice any difference anyway. i'm going to check for updates and maybe install it tomorrow. i'm pretty busy the rest of this week so not sure if i'll have time (too many computers to fix, including my own)

wanted to add, shipping from truckcustomizers was awesome. ordered it monday afternoon and even with this weather it made it here today. thanks to them and to UPS.

 

Here's a question for Scott @Superchips. Under data logging, what exactly is the % Load field supposed to convey? I have a decent concept of what engine load is, but what engine parameter is the tuner measuring and what is the intended purpose to the user to display this data?

 

Go smaller tire size. This should lower the speedo. Will require a little tweeking to dial in with GPS.
Good luck

 

Thanks RedTruck! When I get back from being on the road for work, I'll change it.

 

Here is how the engineer defined it for me:

"It shows engine load percent taken from the PCM similar to how a bathroom scale works. As the load applies weight the numbers on the scale will rise. As the engine works to overcome the load the % will be greater towards 100%."

Hope that helps.

Scott