35s on 4.10s?

tyhuck · July 3, 2013

OK, first let me say if this is the wrong section, I appologise. Its hard for me to decide where to put my topics sometimes.

I have been bitten by the bug again, so I am starting my research now, for a project that might take place a year or so from now. Now, let me begin by saying, I have read all of the other posts about regearing for 35s, and that 4.56 gears will give me more power and are better matched for 35s, and blah blah blah. My question is somewhat related, but a little different than all those topics discussed before (at least the ones I could find). My current truck has factory 4.10s, and gets about 13-14mpg on 285s. My last truck had 3.42s in it and still could pull those numbers on 35s. So, I am thinking that 35s will give me the ability to run a little lower RPM and possibly get a little more mileage out of her. Surely the MPG on 4.10s and 35s would be better than the mileage on 3.42s and 35s, right?

That being said, here is my question.

What is a realistic MPG number that I can expect out of my truck with 4.10 gears and 35" tires?

I know some guys have run 4.10s with 35s, so Im primarily looking for someone with personal experience here. Let me reinforce the fact that my truck already has 4.10s, and I CANT AFFORD TO REGEAR, so dont even start with the 4.56 stuff.

LongrangeLauber · July 3, 2013

I still have 3.73's on 35's and I just keep my truck out of OD and I get 13.5 mpg (around town) so you should be seeing a bit better than that. Probably 14-14.5 around town cause you can still use OD. Its hard for my truck to move while in OD

tyhuck · July 3, 2013

Well, most of my driving is highway driving on rolling hills, so thats what Im most concerned with. With the 285s I can set my cruise at 70 and there are only a couple hills that will cause my truck to downshift out of OD.

blackout07 · July 3, 2013

It would surprise me if you see any better mileage... Specifically on the highway. If you're downshifting on inclines now, it will be worse with 35s. For example my mileage went down when I went from 35s to 37s with my 4.88s. I dont agree with the gearing charts but im "properly" geared for 37s yet i saw a mileage decrease. So, I'm running a little less rpm, but the weight and rolling resistance brought me down. I'd stick with 33s if you want he best balance.

tyhuck · July 3, 2013

Well, as long as it doesnt make it worse. Im just really disappointed that Im not getting any better mileage out of this truck now. I was concistantly getting 14.5 with my 05 that had 3.42 gears, a total of 5" of lift, 35" mud tires, and about 600lbs of extra accessory weight. This truck is 4.10 geared, only on 33" all-terrain tires, and the only extra weight is the camper shell, and Im still only getting 13mpg. That just doesnt make sense to me.

My train of thought was that 35s on this truck would have to give me better MPG than 35s on the 3.42s, right?

Dont get me wrong, I love the look of these trucks on 35s, but I dont want totally kill what mileage im getting now. I guess a trial would be in order. Would it be ok to run different size tires as long as I dont use my 4wd? I ask because I can probably fit a 35 in the rear of my truck now, and that would give me an idea of the MPG and performance I would expect running the 35s permanently.

blackout07 · July 3, 2013

Is this truck a 6.0? I'm sure you could run 35s on just the rear but you would still be pushing less weight up front since the 35's weigh more. Regardless, you will be undergeared for 35s and I just can't see you getting better mileage.

tyhuck · July 3, 2013

No, its just a 5.3. I wish it was a 6.0, then I could justify the crappy mileage.

blackout07 · July 3, 2013

No, its just a 5.3. I wish it was a 6.0, then I could justify the crappy mileage.

So much for my theory. I had a 6.0 with 4.10s and the mileage sucked.

tyhuck · July 3, 2013

Yeah, I had a 6.0 with 3.73s on stock tires, and the mileage sucked too.

I guess I will just give it a try. Its not like im not gonna try it anyway. like I said, Ive been bitten by the bug. I dont know why Im so upset. I havent had a truck that gets over 14 mpg in over 7 years. I guess its just the thought of a stock half ton getting only 13mpg.

STINSAN3 · July 3, 2013

Whenever my 5.3 goes out, I'm putting the 6.0 in it.

blackout07 · July 4, 2013

Whenever my 5.3 goes out, I'm putting the 6.0 in it.

6.2 it !

STINSAN3 · July 4, 2013

6.2 it !

I read somewhere that you can't put the 6.2 in it?

I think Chawkins said this somewhere??

LongrangeLauber · July 4, 2013

6.2 it !

6.2L are kinda pricey, at least the ones I have seen. Get the cheaper 6.0 and do some performance upgrades to it to make the same power as a 6.2L, but for almost half the cost. But I'm also stuck with my 02, and comparing prices between a used LQ9 and used 6.2L (whatever the production code for those are)

And Blackout, your truck looks rediculously tall in your sig pic. I wish mine looked like it was that tall haha

gm4yrs · July 4, 2013

13 mpg is ok for a 1/2 ton v8 4x4, town and freeway driving.

16 mpg for freeway, long trip.

You loose 1 mpg for 33 to 35 tire size, 1/2 mpg for a lift.

My 1992 Gmc z-71 350 5-speed got the same mpg, as my 1999 silverado, listed below.

Prokopchuk_9 · July 4, 2013

FWIW my 06 1500hd on 33x13.5's, 6.0 and 3:73's got 11-12mpg mixed. Highway was like 13-14 if I drove like 60-65mph anything more it sucked it back towing anything more than 2500lbs it got 8-9 and city was like 10 mpg. That was with a very well built 91 octane tune, CAI, full exhaust and port polished heads.

13-14 MPG with 33's and 4:10's is nothing to complain about man...