gear & tire size chart.

[colocruiser303]

im new to the 80 series, just bought mine a few weeks ago. im getting about 11 mpg city with 285. from what i understand the 80s come with 4.11 gears. the gear ratio and tire size chart( http://www.4lo.com/calc/geartable.htm) says that with 4.11's 35s will give you the best gas milage. what are all you with 35s and stock gears getting for milage? I cant imagine how bigger tires would equal better milage. Also would I be able to fit 35's with a 2.5 OME suspension?
thanks for any help. i appreciate it.
-Evan

 

[Romer]

Huh, thats the first I heard bigger tires give you better gas mileage. I'll take that with a grain of salt for a bit.

35's would fit with a 2.5" lift.

 

[Montana Cruiser]

This is assuming that 2600 is the sweet spot for the 1FZ, right in it's power band.

 

[Slomo]

Seems to me that chart is a "rough" estimate at best as it does not take into account your vehicle. The engines size and power band as well as transmission gear ratio's would be a huge part in optimal gas mileage. Plus the extra weight of 35's vs 285's would probably offset the extra distance covered per tire revolution.

 

[landtank]

last I heard we had 4.10s, anyway, I had zero MPG difference between 4.10s and 4.88s with 35" tires, actually 315s.

 

[Jason Andrews]

my MPG got a little better when I swapped to the 4.88's. The lower rpms doesnt mean better mileage. Gotta keep it in the that 2600-2700 range

 

[Rusty Phillips]

I cant prove it, but I think my economy dropped going from 275/70's to 285/75's


even if I drive like granpa (slow enough that school buses pass me)

 

[Nay]

I have 2.5" OME currently, and just upgraded to 35" trxus MT's from 33" trxus MT's. These tires are larger than their metric counterparts.

First, 35's will not fit on OME without shock travel adjustment. They fit in the wheel wells, but will rub without adjustments.

Second...I think the 35's run more in the power band than 33's in Colorado when you are using the OD off and PWR buttons. 70 mph with 35's runs at about 2,800 RPM with OD off, and it was 3,000 RPM with 33's, which as a little high. I have a direct comparison with the same tires, and so far, they feel essentially the same. If you are running 33's on stock gears 35's are pretty much a non-issue. Flatlanders may disagree.

You'll be running lower RPMs on the downhill.

Having said this...I hope you didn't buy an 80 for gas mileage. They are something of a dog at our elevation with no mods (by modern V8 standards)...any lift and larger tires is not going to help you get better mileage. I get about 200 miles on 15 gallons.

But here is your question: how long will it take you to make up $1,200 of 35's tires even if it improved you mileage by 1 mpg?

 

[Bryan E.]

I strongly will disagree that going to 35's will increase your mileage at all, and I guarantee you that your mileage will decrease with more aggressive tread tires. There are several factors that lead to this like more rollling resistance due to tread pattern and tire heigth, increased wind resistance, being undergeared uses more gas than correctly geared, etc. etc.

I like the look of my truck better with 35" MTR's but it will cost you in many different ways. If you want better mileage, don't go here (35" tires) in search of it.

If you still want 35's, there are several ways to fit them, some better than others. I am running OME J springs, L shocks, and lots of other stuff, and this isn't the best set up for everyone but it works ok for me for the time being. I like Tiredom's way of fitting larger tires with stock lift, just go to portal axles. His truck is way cool and you need to search for his axle swap if you haven't read about it.

 

[knorrena]

I dont have an 80 yet, I have a 70, but I do have some thoughts on this. It takes more force hence more energy to spin, keep spinning, or stop spinning a large diameter object compared to a small one. This is more true when the largeer object weighs more than the small. If you want to confirm this go buy a really heavy tire for your bike, say a studded bike tire (yes they do make them). Put em on and see how much more energy you spend trying to keep up the same speed you would if you had lighter tires. The extra energy demands of a larger tire will reduce gas mileage and increase brake wear. My advice is to not use the argument of optimal gearing to meet your engines power band to get larger tires. Get them because you want to.

Karl