dsadsdaiouser

Can anyone tell me what rear gear is in our 2012 GMC Sierra 1/2 ton extended cab 2WD? Here is the tag in the glove box:




Thanks.

Scott

98CayenneT/A

Gu6 = 3.42

dsadsdaiouser

Thanks! We changed from a 245/70/17 tire to an OEM wheel and 275/55/20 tire and even though the circumference only increased 4.4" I'm surprised how lazy it feels now. Acceleration is terrible and it feels down on power. Maybe we need to look into a 3:73 or 4:10 gear?

Scott

98CayenneT/A

4 in. taller is actually a lot and will kill your acceleration, if you're going to do a gear change go with the 4.11's

A-Dub

iTrader: (6)

Its not 4" taller, he said circumference, not height...

The 275/55 20 is roughly 1.4" taller than the 245/70 17.

OP, the difference you are seeing is primarily the rotating weight, not so much the diameter change. the 20" wheel and tire weighs a lot more than the 17s did. It affects acceleration and mileage. FWIW, Id get a tune before I changed gears.

dsadsdaiouser

Thanks! Good idea. I thought of that too. The tuner locally that handles our C5 said he'd be glad to do the truck and could help out the power and mileage.

Scott

98CayenneT/A

Sorry op, I misunderstood a bit and for some reason thought you were going from like 29" tires to 33"

bobfig

imo go with 4.10 gears. i running 3.73's and when i got the truck it had 31.9 ad it was ok but when i got new tires i went down to 30.6" and its just about perfect.