Advice on gear ratio

You should put up your differentials to swap with somebody and get back to 3.73, assuming your are auto and not manual. 4.88 is great for 35-37” range tires. Not 100% sure on 07 but I think you change the plastic gear cog on yours for the speedo. Later years, were read off the speed sensor at the wheel.

At the bottom of this page among all those buttons is one called tire size calculator. You can plug in tire size and gear ratios to see the math more easily and help you make your decision. Swapping diffs is fairly simple and a lot of people would be willing to swap for 4.88s

 

Ha ha! Couple of gearheads buttin horns

 

I feel your pain bro, but if you are having problems with those pulling your tires then I'm pretty sure my tires would kick their arse!

 

Where in FL are you? Hell I’ll bring my truck and we can swap front and rear diffs haha

 

That is probably the easiest solution!

 

Great post on the tire size calculator, many thanks

 

According to the interactive tire size calculator posted by zippsub9 the ratios closest to factory ratio is the 4.27 or the 4.56

 

But your truck's wheels and tires are heavier and your trucks aerodynamic drag is much higher.

 

The most economically feasible option is to sell the truck and buy something else. With that size tire the aftermarket ratio is about right to get everything copacetic. In other words unless you also change the tires back to factory size you need to leave the axle ratio just as it is. Any higher gears with those tires will result in poor performance and even worse fuel mileage.

Those tires are about 12% larger than stock which means you're odometer is off by 12%. If the odometer says you've driven 250 miles, you've actually driven about 280 miles. You need to factor that in when calculating fuel mileage, you're getting better fuel mileage than you think.

 

3 ply vs 10 ply. E rated are a ton heavier so more rotational mass that will kill MPG.

 

Changing gear ratios for better gas mileage a lot of times is gonna result in disappointment. I have an auto v6 with 33’s and 4.30 gears, fuel economy basically unchanged. 14-15 combined However, I didn’t change gears for mpg I did it because my truck was a dog. The bigger issue at hand in my opinion is we are still limited to a 4.0 v6 that in my experience doesn’t do well running at higher than stock rpms on the freeway. The only other viable option is the super charger but that’s gonna run $5-6k. With that said, I think if the OP wants lower highway rpms, then this is the perfect time to upgrade to 35 or 37 inch tires

 

Hello all. I am currently researching whether I should regear my truck and there seems to be a lot of enlightened minds here. I have the factory gearing with 285/75/16 e rated tires on trd O/R rims on a 3" lift. I also run a bed rack with a CVT RTT. My trouble is that when I drive to Tahoe in the summer time My truck has trouble bringing that weight up and down the hills at anything over 65mph and I feel bad for the drivers behind me because it's a two lane roadway. Should I regear or make the best of what I've got?

 

Regearing is expensive especially a 4x4. As shitty as this sounds you might be better off downsizing your tires

If you do regear this is the basic formula:

33 tire, auto = 4.30 or 4.56
33 tire, manual = 4.10 or 4.30

 

I have a prerunner, does this worsen my situation? Cost wise to have it done at a professional shop what may I expect? I hear you on the tires. I knew they were not necessary for the things I was doing, but goddamnit they put a smile on my face

 

@Aarophi

I'll add to that from the information I've read on here......you may want to look at:

33" tire, auto with armor and other weight with the possibility of going to 35's = 4.56 or 4.88.
33" tire , manual with armor and other weight with the possibility of going to 35's = 4.30 or 4.56.

 

I know what you mean, 33’s look to damn good on these trucks. For me, when the time comes to consider a new truck, I might just say screw that and add a super charger to my current rig

 

You’re in a good position. You only have one differential to worry about. Here is a rough breakdown of what to expect to pay for a regear. You might also want to add a locker or a Tru Trac LSD depending on your situation.

Gears = $200-$250
Tru Trac = $550
Install kit = $200ish
Labor = $300-$400

 

The advice offered in this thread is sound, but people don't want to hear it. The parts of the equation that get overlooked are HORSEPOWER and TORQUE. An engine only makes so much, and the lower the RPM, the less it makes. The reason gearing is essential for bigger tires is that it takes way more power to turn them. The engine has to produce more power, so it has to turn faster to get higher into the torque curve. Yes, that means lower gas mileage, but if you drop the RPM to where the engine is struggling, the MPG will go even lower, and the truck's performance will go from bad to worse. You cannot gear yourself out of a power deficit. In these trucks, if your tire/wheel combination is over 75 pounds, you are going to have significant loses in either performance or MPG or both. End of story. It's time to supercharge or do a V8 swap.

What someone needs to create is a calculator that takes into account: tire weight, wheel weight, engine power curves, truck weight, gear ratio, and intended use. But of course no one would like it, because it would tell you the truth about those ultra cool oversized tires. Big wanker and no balls.

 

I completely disagree and my truck is proof enough for me.

 

Good for you. I wish I could defy the rules of physics.