trade in 5.3 for a 6.2?

nards444 · October 9, 2014

Bigger wheels yes, but when we get 18s 20s or 22s from the factory it is the same size tire on a bigger wheel. So what you are doing is reducing the tie side wall to keep it the same on the increased rim size. If you have a 1" side wall you have almost no flex or it would let the room hit the road. This lack of flex kills ride quality making it rough but also reduces the energy loss from the flex. Remove wind friction and a 22s will coast longer in neutral that 18s.

Heavier wheel take more torque to spin, but once spinning take more to stop spinning. That is why if you have large wheels you should have large brakes. This also means once rolling they take less power to keep rolling unless they are mud tires which will have more flex and aggressive tread patterns.

Tire width also plays in, skinny will get better milage.

Not sure man. Like to see some data on this. If this was true semis would get better gas mileage than trucks, and trucks would do better than cars. If something is heavier typically it takes more energy to move it and stop it

seansharley · October 9, 2014

I guess I will be the first to call BS on this. There is no way in hell these trucks will get over 20mpg going 80mph plus.

Seriously, I don't work for GM, why would I lie?

olegachevy · October 9, 2014

Seriously, I don't work for GM, why would I lie?

That is awesome man! Kind of thinking I should have spent the extra money and went with the 6.2 for towing purposes. I am going to try and keep my speed at 55 mph the next time I take my trailer out to see if the mpg improves.

redwngr · October 9, 2014

sean, you're not really trying to tell us you drove the last 50 miles at 95mph? .... on flat ground?

redwngr · October 9, 2014

Bigger wheels yes, but when we get 18s 20s or 22s from the factory it is the same size tire on a bigger wheel. So what you are doing is reducing the tie side wall to keep it the same on the increased rim size. If you have a 1" side wall you have almost no flex or it would let the room hit the road. This lack of flex kills ride quality making it rough but also reduces the energy loss from the flex. Remove wind friction and a 22s will coast longer in neutral that 18s.

Heavier wheel take more torque to spin, but once spinning take more to stop spinning. That is why if you have large wheels you should have large brakes. This also means once rolling they take less power to keep rolling unless they are mud tires which will have more flex and aggressive tread patterns.

Tire width also plays in, skinny will get better milage.

Torque to turn the wheel, and torque to stop the wheel, are insignificant to the torques required to push and stop the truck.

seansharley · October 9, 2014

I went from Fla to NY, the best mileage I got (24) was in PA, go figure, worst roads, best mileage. The posted photo was taken in Florida

nards444 · October 9, 2014

I went from Fla to NY, the best mileage I got (24) was in PA, go figure, worst roads, best mileage. The posted photo was taken in Florida

anybody with this new DIC can get these numbers as its capturing a relative small amount of miles in 50. Look at the onstar app or do a hand calc on your MPG over a tank, your not getting that type of milegage on sustained distance.

KARNUT · October 9, 2014

Im not going to say 24 MPG cant be done for a tank of gas. I got almost 22 at 72 MPH for 250 miles on 1-10 in Texas with a 342 gear. Last time I was in PA the speed limit was 65, so with a 308 gear pumped up tires one person in the truck no wind 24 MPG over a couple hundred miles is doable.

Chevyman3308 · October 9, 2014

Im not going to say 24 MPG cant be done for a tank of gas. I got almost 22 at 72 MPH for 250 miles on 1-10 in Texas with a 342 gear. Last time I was in PA the speed limit was 65, so with a 308 gear pumped up tires one person in the truck no wind 24 MPG over a couple hundred miles is doable.

Yeah but he is claiming 22mpg at 80mph. Not happening.

diannabill · October 9, 2014

Mine is my grocery getter/daily driver.

Same here

Higgs Boson · October 10, 2014

Torque to turn the wheel, and torque to stop the wheel, are insignificant to the torques required to push and stop the truck.

Unsprung weight has 4 times the effect of sprung weight.

Losing or saving 10 pounds from a wheel is like 40 lbs off the truck.

This means 10 lbs x 4 wheels + 10 lbs x 4 tires = 80 lbs of unsprung weight which = 320 lbs off the truck......except that unsprung weight has a direct impact on braking, handling, acceleration, etc......Sprung weight can be managed, the suspension can be set up for it, etc.....Unsprung weight is very important.....most truck people dont even think about unsprung weight.....and it's exactly what kills MPGs they all try to tune back in unsuccessfully.

I tune lots of trucks, vettes, camaros, etc and its always the truck guys that say, can you improve my mileage? lol.....yeah sure, remove those 35s, that's a free tip.

October 10, 2014

I have seen 20mpg in my duramax with factory tires on the highway, but not at 80, more like 65.

redwngr · October 10, 2014

Sprung/unsprung has huge impact on handling, I agree.

And I also agree on the mpg impact of large tires and lifted vehicle heights. (lose the 35's, lose the lift, etc)

But correcting the math, 10 lbs per wheel = 40 lbs per vehicle, even with 4 times the effect (if it's 4 times and I have no info oe way or the other) is still only 160 lbs in a 3500 lb vehicle that also has huge frontal area (compared to vettes and camaros) .

Higgs Boson · October 11, 2014

Sprung/unsprung has huge impact on handling, I agree.

And I also agree on the mpg impact of large tires and lifted vehicle heights. (lose the 35's, lose the lift, etc)

But correcting the math, 10 lbs per wheel = 40 lbs per vehicle, even with 4 times the effect (if it's 4 times and I have no info oe way or the other) is still only 160 lbs in a 3500 lb vehicle that also has huge frontal area (compared to vettes and camaros) .

math is correct if you reread, the wheel 10 lbs each and the tires 10 lbs each......that's 20 lbs per corner.....80 lbs of unsprung weight x 4 is 320. and this is being conservative.

that is over 3 tents in the 1/4 mile or a loss of about 35 hp. and it affects handling and braking even more than that but the effects are harder to quantify.