Tire sizes and gear ratios revisited

[HenryJ]

Thanks in advance for your input here. Many times I seem to put the blinders on and only see what works for me. I'm trying to get a little more information for an idea that I am working on.

What I need is to get an idea of the maximum acceptable tire size for a given ratio, as it relates to highway and city driving.

This is going to add another factor that has not been previously discussed. The tires weight.

This is the information that I would like (tirerack.com is a good source for specifications):

My 31x10.5-15 Yokohama Geolandar AT+II's measure 30.6" tall and weigh 45 lbs each. I have the 3.73 ratio.

Along with a brief explanation of your satisfaction, or dissatisfaction , mileage and any thoughts:

I feel that my truck has acceptable acceleration and power for passing at highway speeds. I am able to pull the grades in my area easily.
My mileage in the city is usually 15-17 mpg and on the highway the best would probably be about 20 mpg.

I felt that my stock optional size tire of 235/75-15 and the 3.73 ratio offered better performance, but the increase in tire size has been compensated for with engine performance modifications.

[jeggers]

I would go with 31" and 3:73 that is what i had on my 01 and i got 16 to 17 mpg average.

The 32" and 3:73 i dont drive it ever y day so i will check it out but being so tall i would guess less than 15mpg

Yokohama Geolandar AT+II 32x11.5-15 , 53 lbs , 31.5" tall - How is the performance? Added specs-HJ

[CrazyChaz]

Right now I have BFG AT's 235/75/15(35 pounds each and 29" tall) with the 3.42 ratio.

I get about 16.5 MPG combined with my current tires, I havent found them hindering my performance at all, I have used my HPIII to change shift points and firmness so maybe that helps since I only have the 3.42 gears? I probably wouldnt go anything higher than 235/75/15 for the 3.42 ratio though.

[jeff024]

Im running 245/65/17 TOYO ATs overall height is 29.5" with a weight of 31.1lbs
my rim weight is 26lbs
3.73 gears
HPPlll
I average around 18.7 MPG

I think overall my truck performs the same as stock or better with other mods the only thing I do notice is at serge at 45-50mph with the HPPll and have tried all settings without the HPP everything is fine.

[F9K9]

Yokohoma Geolander A/T Plus II 30x955 SR15, 29.5" tall and 40# each. 3.73 gearing. HPP III with modified shift points but, adjusting tire size from stock 235/75 15s was unsuccessful. 2 GPS units puts my speedometer dead on with factory setting. No noticeable difference in mileage or performance.
13-15mpg in town, 20 mpg on interstate.

[quickbiker]

What's the question of the poll? I'm so confused.

[Walt]

I went with BFG All Terrains.

Diameter is 30.7"
Weight is 41 lbs.
Size is 31x10.5x15
Truck has a 3.73 gear ratio

Only real performance mods are the HPP3 and an Airaid Intake.

No noticeable difference in mileage. 13 MPG in town, 16-18 highway.

Some difference in performance from stock 235x75x15 Wranglers.
I'm using the HPP3 to alter the tire size and shift points. Truck does not accelerate as well. First and second gears are ok, but third and fourth gears are sluggish. Braking has changed a bit, still stops the same, but requires more pedal travel.

All in all, the truck is not quite as much fun to drive as it was with the stock tires.

EDIT: I took a look at my air filter last night....big problem there. The Airaid filter was almost ruined (I guess it had something to do with my last fight with a mudhole), so I bought a K&N and installed it, and also relocated my IAT. Truck performs much better now. Still not like stock, but close.

[adrenalnjunky]

What's the question of the poll? I'm so confused.

I'm with QB here - the poll seems confusing - are we supposed to be entering the tire/gear ratio we're currently running?? Otherwise I don't see why 29" and 3.42 isn't just as good an answer as 31 and 3.73?

For the poll - I just answered with the setup I'm currently running.

It seems like you would get more data from havig a separate 3.42 and 3.73 poll, since youre asking for opinions on each, but we're only allowed to vote once.

[gocntry]

I'm Still Running The Stock Goodyear RT/S 235/75R15 Tires With The 3.73 Gears, 28.9 Tire Diameter And 30Lbs Each.

[jeff024]

thats what I put the size im running now

[HenryJ]

What's the question of the poll? I'm so confused.

I'm with QB here - the poll seems confusing - are we supposed to be entering the tire/gear ratio we're currently running??

What you're running , or have run.
There are plenty of opinions. Vote for what you are running, not what you wish that you were, but have not tried yet.

[bwenny247]

currently running 3.42's with 33X12.50 Dayton MT's, overall height 33", tire weight 54 lbs. wheels i'm going to guess about 24 lbs

I've dove into the engine for power and feel acceleration isn't terrible but you just have to make the engine work a little harder to scoot. braking takes more effort but is still good. climbing hills, windy conditions, and towing affects performance just like any truck.

i will say the one good thing to having big tires and small gear ratio is the gas millage. 17.81 is the best i've ever got, 13 is the worst, i average 15-16. which is just about the same as i was at when it was stock.

[apcrews10]

I am running the stock 235/75R15 with about 40 psi. The best fuel mileage i got was 21 and the worst i got was 17. Have the 3.73 gear. Engine is all stock.

[jeggers]

12mpg 31.5 and 373

[coffeedrnkr]

33x12.5's and 4.10's

I get 15.5 mpg on the freeway and probably like 12-13 around town.