Jeteys5.3

iTrader: (4)

hey guys, i like to make my truck faster, but i do use it in the woods and stuff alot using it often. Ive been thinking about putting some 285/70/17 Kuhmo AT's under it with a small crank up front. Now how bad with my 4.10's will i notice a performance loss? noticable? How about mpg? ive been getting 21.5mpg at 68 with cruise on during the 200 mile trip from home to school. Ive been happy and not really wanting that to drop below 21 if i can help it. Mind thats what i was getting before my tune, so ill test what the tune helps out next weekend. Just curious if i should go this route or just get some 265's again in a strong AT and still crank......thanks

GMCtrk

iTrader: (27)

taller tires will effectively make your gear ratio taller. You will run lower rpm's on the highway and get better mileage. You'll lose some off the line acceleration and throttle response. I went from 30" to 31.5" tires and lost a noticebale difference down low

BlownHD

iTrader: (2)

When I went from the stock 245s to 285s I definitely lost some power, but got better off road performance, going to a 285 will probably cause a decrease in mileage, you might be lowering the rpms, but the truck will be sitting higher off the ground, allowing more air to flow under the truck, creating drag, plus the 285s have a much bigger contact area on the pavement, creating more resistance, and lastly the truck might downshift more on the hills. All said 21mpg is awesome in a truck, and I don't think it will hurt the mileage that bad, all depends on how you drive