Tuner/tire size/speedometer questions

[twr]

Hi do you know if the other owner had changed rear gears? If he did and never had the speedo recal that could be why the speedo reads fast. Also alot of guys change gears when they change to bigs tires because the trucks don't have any balls. Check the gear ratio first if your truck is 2003 to 2007 it came with 4.10 hope this helps.

[HUMMERICH23]

So in 08 they switched rear ends to 3.73 then? Why didn?t they just keep the 4.10? So if you put 37's on an 08 or 09 is re-gear like a mandatory upgrade then?

[guruerror]

Originally Posted by HUMMERICH23

So in 08 they switched rear ends to 3.73 then? Why didn?t they just keep the 4.10? So if you put 37's on an 08 or 09 is re-gear like a mandatory upgrade then?

May not be mandatory but it would help keep you in your power band...

Check out this calculator: http://www.4lo.com/calc/geartire.htm

Looks like you may want to move to 4.10s.

[PaHumBug]

Originally Posted by twr

Hi do you know if the other owner had changed rear gears? If he did and never had the speedo recal that could be why the speedo reads fast. Also alot of guys change gears when they change to bigs tires because the trucks don't have any balls. Check the gear ratio first if your truck is 2003 to 2007 it came with 4.10 hope this helps.

I don't know if the gears were changed, but wouldn't re-gearing make the speedo read slower instead of faster? Or is my thinking backwards...

I can adjust gear ratio with the programmer too, maybe I should play with that???