tires that came on my tacoma causing mpg loss?

the tacoma i own is a 2006 4 cylinder, access cab 2x4. i seem to have an average of 18.5 and thats if i baaaby it. i keep everything under 2000 rpm's pretty much no matter what. the truck came with 20 inch rims. "255/45/20" i was wondering if that is enough to keep me away from the 21-22 i would really like to achieve, i drive almost all highway. i havnt done any mods from the mpg thread 2nd filter ect ect. thanks - Brandon

 

yes, so are big tires, and rolling those with the 4 cyl = worse gas mileage

 

true that, ive seen members on here with all terain tires and smaller rims achieve better mpg then i. maybe its a weight thing to, didnt thing about that

 

from the online tire size calculator

the diameter and circumference of the wheel are lower correct? so that rules out the bigger tire issue. " forgive me if im wrong, if i knew this stuff i wouldnt make a thread about it" so is it just the weight of the rims?

 

I would bet it's your air conditioner causing the drop. Your other option is just using the vent with no ac since running with windows down will also kill mpg.

 

thats what i was looking for, my gf's father and i played with numbers today and figured that out. this solidifies it. thanks. i almost always have the a/c cold that doesnt help either haha

 

Your taking into account the larger tire size when calculating your mpg correct?

 

i knew that it was causing the problem, thats the whole point of the thread haha . i dont think my truck was reprogrammed for the new tire size, causing the odometer to show slightly less miles driven due to the bigger size tire. " moving further with less rotation"

 

Use a gps to get your actual speed. Then you can figure out the speedo error.

 

Stock 5 lugs will easily get 25 MPG. If you primarily drive on the highway, you should see over 26 if you know what you're doing. Get rid of those gangster wheels and you should see an improvement.

 

yea going back down to 16 inch rims when the tread on these tires is low

 

You could have close to the same circumference as the stock tires with a 20 inch rim. You would need to run a 255/35R20. This would get you very close the stock tire.

from the online tire size calculator





from the tire calculator

 

I agree. I was just saying it CAN be done on a 20 inch rim.

 

The difference that is the biggest cause of the milage being so low is the weight and rolling resistance of the wheels and tires.

Just for fun take the spare off if it is stock size weigh it and weigh one of the 20" set ups.
Moving heavy wheels and tires eats up gas milage.

 

Sorry if this was covered already, but whats the reason for the offset?

 

Yeah it's not just the weight of the heavier wheels making it a heavier truck overall, it's also getting the extra wheel weight spinning... bad fuel economy and more brake wear too, just a bad deal. The stock steelies are no lightweights, but many of the custom street setups are particularly bad in every way except cosmetic appearance and maybe cornering grip. I won't even get into the additional unsprung mass.

 

Math solves all. Let me throw this out there.
Would a a 16x8 rim and 265/70/16's be better on mpg
due to the smaller rim weight even though there a bigger
Tire overall?

 

I understand the concern to get good gas mileage with the high prices at the pump today. But, don't you want to enjoy your truck while you are driving. There are other options out there as far as fuel efficient vehicles are concerned. I was a gas mileage junky for a while and have finally figured out that while I am worrying about gas mileage I'm not having any fun driving my truck. So I said let the mileage fall where it may, fill up the tank, crank up the A/C, and hit the highway and drive it like you stole it. I did just that and on a 300 mile trip traveling at 80-85 on the highway, I still got 24 mpg. Now I could have gone 70 shut off the A/C and sweated it out and got maybe 26 or 27 mpg. But I bought my truck to enjoy the things it has on it. Now my truck is only 6 months old so if I was that concerned about gas mileage I could have bought a Corolla or even a Prius Hybrid. Just do the best you can with what you have and if the cost is a concern use some of your free time working for extra gas money. I said "some" not all your free time.Maybe a senior citizen needs weeds pulled or lawns mowed or hell even do their grocery shopping for them, but please enjoy your truck. Put on what you like to make it yours, because you enjoy it and you want it that way.

Sorry for the rant but I don't care what the price of gas costs as long as I don't have to wait in a line to get it. I went thru the other gas crisis and it wasn't fun. Hell, I remember my mom calling me crazy for paying 65 cents a gallon for Sunoco 260 premium fuel back in the 70's for my 65 Chevelle. That 327 wanted to rev and needed the high octane. Could have gotten gas for 48 cents instead but the Chebby wouldn't run on it. Also remember in 79 being only able to get 5 bucks at a time, and there were lines wrapped around the block to get the 5 bucks worth. Of course that would get you 5 gallons but my 78 Trans Am only got 15 mpg. That 400 ci engine was thirsty. To put it all in perspective just do the best you can with what you have and enjoy it.

Thanks for listening and letting me rant.

 

Yes I did. But it is a 5 year old truck running 20 inch wheels with 10 inch wide tires. Not sure how many miles it has but- have all the fluids been changed?
Have the spark plugs been changed? Are the coils in good shape ? Is the throttle body clean? Are all the filters in good shape, air, fuel and oil? Is the parking brake properly adjusted? Are all the vacuum hoses hooked up or in good working order (not dried out and cracked) Is the thermostat working properly or is there even a thermostat in it? Is the radiator working to its full potential? Is the belt in good shape? Has there been a compression test done on the engine? There could be cracked or broken rings in it? Is the bed filled with 500 lbs of stuff? All these things contribute to your gas mileage not just the size of your wheels and tires. Now don't get me wrong the size of the wheels and tires are a MAJOR factor but not the only one. Gotta look at the big picture not just one element of it. It's always the little things that ya forget about that creates the most havoc.

 

It will be getting a tune up soon only 57,000 miles. You do make a point i will be
Making the truck mine, i plan on doing what i want and making it mine
"Smaller rim, big tire setup" I'm just trying to find out if
the wheels are my main cause of 20 mpg which isnt bad from the
16 mpg i used to have with my mustang