what gas milege does everyone get? since i have changed my tires to 32" ATs mine dropped about..50-60miles per tank(full tank until first empty light comes on). I ran both stock and also ISR and deck plate, changed plugs and cleaned injection/throttle body but that doesnt seem to change anything. I get about 230mi per tank(until first Empty light) when i only run on freeway tho..i get about 270mi. I guess bigger tired do make a lot of difference. When my rig was stock everything, i got about 300mi local and 340-360 freeway. Thank god i only drive 15mi. a day:cry:

 

Ray,

I experienced EXACTLY the same thing after switching to Revo 32s. I used to get on average around 18-20 mpg. Now I get around 16.5 to 17.3. I cleaned out my TB and replaced my spark plug wires and plugs and it up'd my mpg up to around 17.5.

Anyways, this will be my last set of 32s. I'll switch back to 31s but most likely an 'aggressive, chunky' pattern like BFGs.

Bob

 

remeber that bigger tires also put your speedo and mileage out of wack. Even a small difference , over the course of a tank of gas will make a huge error in gas milage calculations. It is probable that the actual change in mileage is really small.

 

pho,

nope, i verified my numbers with my gps on 4 tanks total.

bob

 

time for some Z-MAX!!!!!!!!!!!!! J/K . I wonder if that stuff really works...i've used all of those junk to my previous car before but never any results. NE ways i'm glad to find out that im not the only one with this problem... thanks

 

lol... it's sad.. my 87 pickup is stock and i was getting 12 mpg not too long ago (haven't checked after i changed the fuel filter and air filter)... I need to have someone look at the carb... This guy that was doing motor mounts for me "adjusted" it...

 

hey fellas i was just wondering that if you change the gear ratios will that bring the mpg's back to stock. i was thinking of running 33's with 4.88 gearing. i know that is pretty much the same final drive ratio.

 

i think the reason that the milage goes down is the increased rolling resistance, not the fact that it's harder to turn over the wheel.

a bigger tire will (generally) have a larger contact pacth with the road and have more room to "squish" when weight is put on it. you loose a lot in the squising of the tire (this is why trains have small steel wheels, it dramatically reduces rolling resistance because there is no energy loss in the squishing of the wheel)

i also don't think regearing will help that much anyway because (with all else being equal) a larger tire just acts as a higher ratio, we all try to cruise in 5th rather than 4th because we spin the engine less and get better milage. so (within reason - until you're bogging the engine) larger tires should help milage.

one thing that would be neat to try is to keep the width and sidewall size the same and just increase the diameter of the wheel and see how milage changes.

just as a side note, i get the same milage on my truck when i run my 31x1050 summer tires or my 30x950 winter tires.

 

Before - 28" tires on 15" steelies

18-20 mpg

After - 32" tires on 16" alloys

15 mpg

3.90 gearing

 

9.7. If I really baby it I can get 10.2

 

re-gear....the engine has to work harder to spin larger tires with stock gears....Toyota puts certain tires with certain gears for a reason

 

what i wonder is, since the stock ratio was 4.37 on my truck with 29"(?) tires, should i regear to 5.29 with 4.88s to set things right?

i wish there was something between 4.88 and 5.29 with toyota diffs, like a 5.13. that would be a good compromise