I have 4.10 and have 35" tires. The truck has all the power in the world but anything over 70 she putters out a little bit. I get 17mpg at 70. When I go faster the gas mileage falls through the floor. Should I switch to 3.73's?

 

thats a good question i cant answer... but if you do change out to lower gears, i might be interested in buying your old 4.10s... i only have 3.55s...

 

3.73's are a great gear IMO. I went from 4.10's to 3.55's and I want to get 3.73's now. I miss the get up and go of the 4.10's, but the 3.55's are great on the highway.

if you do a lot of highway but still want better acceleration I'd go 3.73's

 

what exactly do you mean here? do you mean it putters out as in it has no power? if so, dropping to a 3.73 will only make the problem worse. with 35's you are probably already close to a 3.55. dropping to a 3.73 will put you somewhere in the 3.15 to 3.20 range. generally when people go with bigger tires they go with a lower gear ratio(numerically higher like a 4.30 or 4.56). bigger tires=more rotating mass/loss of gearing/have to run it harder to gain or maintain speed, etc. all that kills your gas mileage. going with a higher gear ratio will mean youll just have to run it that much harder and will lose that much more mpg's.

 

I mean the rpm's are getting a little high at the top end on the freeway. It has plenty of get up and go. I just want to bring the rpm's so the mileage will improve at 75mph

 

Doubt your gonna do much better fuel milage wise. Your end up pushing so much air when you get up 70+. I would keep the 4.10 other wise your gonna loose alot of low end. My truck had terriable acceleration with 3.55 towing in stock form.

 

I have a buddy of mine that has 33's or 35's and 3.55 gears. He is getting 21 on the highway and 17 in town. It makes me jealous, LOL.

 

I wish I would have kept the 4.10's in mine... And I only have 33's. With your 35's I think you'll be happier with 4.10's

 

I turn 2500 at 70 and 2700-2800 at 75. I still have plenty of speed. I would be glad to race someone with a 65 mph kick. That is when it comes alive. Different mods, I know.
But still, if you want more speed it probably isn't the tires but maybe the mods. What mods do you have? Again I agree if you went 3.73 or 3.55 you would be sorry.
If you want 3.73 I have an open style carrier in my garage. I will ask the owner if he wants to sell if you want. Let me know.

 

Is that pic from the Oregon dunes? Looks really familiar, LOL.

 

It sure is. Good guess. We go up there every year for Presidents weekend. Great times.

 

The dunes near Florence?

 

X2 what wmiller said. i saw a study a year or two ago where they said you lose something like 2 mpg for every 5 mph you do above 55 mph. the lower the rpm's you turn, the harder you have to work to push the wind. the higher the rpms you turn the more fuel you burn. they also did wind tunnel testing and showed that the faster you go the more the wind behind you acts like a vacuum as well. so not only do you have to break the wind(no pun intended) in front of you, but you have to accelerate harder to escape the wind thats pulling you back.

 

Trucks create a different vacuum then cars do, if you have an open bed I mean.
The null space is created more in the bed of the truck, instead of behind it. So your transporting a vacuum.

33's here, with 4.10's. 2600 at 70. I'd love to have just a second over drive.
So, i'ma go with cody on that thought and throw in an overdrive kit.

 

i cant speak about the wind tunnel testing, but i did my own mpg tests and they were pretty much dead on with what the study showed. i lost exactly 4 mpg going from 55 to 65.

you bring up an interesting thing about transporting a vacuum though....going back to my physics classes we were taught that things are weightless in a vacuum. so in theory, if we drive with our tailgates down, we should have infinite payload capacity