I recently installed a 2.5 RK lift and replaced the stock Rubicon wheels and tires with 35's (the actual size is 33.75) and my speedometer and GPS speeds are reading the same. Is this normal? I didn't measure the actual size of my stock tires while they were on it to compare. Just thought I was going to have to recalibrate.

 

Not normal at all. What was it reading before the tire upgrade?

 

I didn't compare speedometer to gps before the upgrade thinking the speedo was sync to the stock tires. Wandering if I need to go ahead and buy a Procal to upload the new numbers anyway?

 

I don't know about the 730n, but on the 430n the Nav gets its speed reading from the Jeep, not from it's GPS. It's stupid, but that's how it works.

 

I've got the 430n and if that's the case your have answer my concern......thanks!