Larger tires. To tune or not?

[pasty]

I believe all of these trucks have GPS for OnStar. I don't understand why the trucks can't monitor the GPS and autocorrect the speedometer or an option on the dash computer to do this while you drive down the interstate. This isn't difficult.

[Silverado4x4]

I believe all of these trucks have GPS for OnStar. I don't understand why the trucks can't monitor the GPS and autocorrect the speedometer or an option on the dash computer to do this while you drive down the interstate. This isn't difficult.

Well for one, OnStar is not in all new trucks and what you think would happen when you loose Satellite signal which does happen a lot,,,, no speedometer.

[pasty]

Well for one, OnStar is not in all new trucks and what you think would happen when you loose Satellite signal which does happen a lot,,,, no speedometer.

I'm thinking GPS is not the only source of speed, think of a tunnel but is used to verify the speedometer accuracy. Initial thoughts. Every 100 miles at a speed above 50, it will calculate your speed over a distance of a mile. If certain criteria is not met such as maintaining 50 mph or losing the signal the results are not applied.

 

I verify my speedometer with an app on my $500 phone. I don't understand why I need to keep a mental note of the actual speed of my $50000 truck. Why can't it figure this out for me?

[etton]

I put 275/65R20 34.1" tires on my truck. I havent tuned it and dont know if I will. How far off is my speedo and the mileage on the DIC? The AFM doesnt come on as much either. I wont do anything that might void my warranty.

I Little off topic but do ur 34.1 tires rub at all?

[Crooks]

Very little at full lock with the wheel to the right in reverse. I hear it rub less then once a month and I just ignore it. It happens so little and st very low speed.