What’s your mpg on 295/70R18

I have a question aout this. You increased the tire size so wouldn't the odometer that you are using to calculate the mileage also be off now?

Falkens say 305/65/18 is 33.6" X 12 on a 9" wide wheel

Toyo AT/2 295/70/18 is 34.3 X 11.8 on a 8.5 wide wheel

So a 2.1% increase in size and 11 less revolutions per mile. That adds up.

Someone better at math will probably have the answer but I am thinking the combination of the odometer being off even more and the increased tire size might be the issue.

 

You are right. I’m not sure how to calculate it either so I hope someone smart will chime in!

 

@nowayout but how does @TheBeast het 14-15mpg on the exact same tire setup as me is what I’m wondering. We would both be off on calibration.

 

Not sure about that. My brain is hurting lol.

There can be a lot of variables. Who knows what his mileage was before his lift and tires? Did he regear? Did he have his speedo calibrated? Maybe he drives like grandma, no offense if you do TheBEast

 

I had 33x12.5x18 before and they actually were heavier by 1 lb each corner. I was already getting 14-15 before so it didn't change

 

maybe you have dirty air filter or fuel filter ?

 

I also run 41 psi per tire.

 

I have 295/70R18 Toyo AT and I just got 15.2 on a trip from Phoenix to Camarillo, CA

 

....just got this today on a 4 hour trek on the highway 295/70/18...Coopers

 

I am running the exact tire with 2 1/2 in the front and 4 inch lift in the rear. I moved from stock tires with the lift. My actual mileage has on average Gone from 15.5 to 16 down to just under 13 to 13.5. Calculated by hand and unigage. Both methods average slightly better than the trip computer. I have a 180 mile trip I make multiple times monthly so great place to compare.

 

And here is my alignment specs

 

I think comparing the average mpg is sort of meaningless. There are too many variables I get somewhere in the 15s on highways. But because my town has relatively small distance between stop signs/signal lights, and because of winter warmup time, this is my current average mpg readout.

 

x2

The 11ish MPG's I was getting was in town driving (small town, mostly short trips with lots of stop and go). On the highway I was getting 15-15.5 before re-gear. I would think 16-17 on the highway after gears, but haven't tested yet. With stock size I was 13-14 in town, 17-18.5 highway.

 

How the hell are you getting that kind of mpg? I can’t get above 13 lol. Is that same as when calculated by hand?

 

I literally saw an Arco (AM/PM) truck filling up the tanks at Costco.

 

If I do ALLLLLL highway, and drive slow like my drunk great-gramps when he didn't want to get pulled over (without all the swerving and cussing, of course), I can get 14 out of it. Regular driving, which is still 60% highway for me, is low 12s.

 

This picture was taken after resetting fuel economy while driving 55mph down a hill.

 

U are one lucky guy.
When I do all of the above, I get 12 & 10mpg consecutively.

 

I guess we drive the same because when I am on the highway I usually don’t drive below 75 so with the speedometer corrected it’s more like 78-79 lol. I’ll shut up about my shirt gas mileage now!

 

First full tank today on the new 295's hand calculated was 13.8. Down from about 15.3 average pre meats.

 

Highway miles. ..yes

 

Highway miles

 

I noticed this too with my at2s I was getting 15-16.5 with my 275/70r18 bfg ko2s and now with the 295 toyo at2 extreme I'm getting 13-14 mpgs. Tires are taller yes but only weigh in at 6 pounds a piece difference

 

I average about 11.6, which is mostly driving in town (with a lot of hills, MPG per the trip computer). I took a trip up to LA and the freeway driving got me up close to 14. I did lose some MPG when I switched to the larger tires, but got some of that back with a tonneau cover.

 

Before I put on bigger tires and a lift, I was averaging around 17.0 - 17.5 mpg. I put on my 295/70/18s prior to getting the lift, and I noticed a couple of things just with the bigger tires:

1. With my stock tires, my speedo was always slightly off. I was always going slower than what the speedo said by 1 - 3 mph depending on my speed. After jumping up to the 295/70/18s, I noticed that my speedo seemed to be almost dead on. This got me wondering if Toyota was somehow intentionally screwing with the speedo gear to make it appear that you were getting a fraction more mpgs. I talked to some other Tundra owners, and decided that this probably wasn't the case, as most of them with stock setups had accurate speedos. Then, I thought about the fact that my truck has the tow package, which has 4.30 gears. Standard Tundras have 4.10 gears. Looking at my fuel mileage calcs, I realized that my Tundra's odometer must have been calibrated for 4.10 gears. The bigger tires just canceled that out. The only reason I point this out is that you might check and see how accurate your speedo is. If it was calibrated incorrectly, your mileage won't be quite right.

2. With the bigger tires, I immediately lost about 1 mpg (part of that was the error introduced by my speedo). I was getting around 16-16.5 mpg.

Then came the lift. With that, I lost another 1-2 mpgs. Now I get around 14.5-15 mpg in the winter and 15-15.5 mpg in the summer.

 

Makes sense. The higher you up the more drag you create. My Speedo was off like you too stock. I believe manuf can be as far off as 3%. Now with my 295’s when my speedo says 75 I’m really doing 78-79 according to my gps.

 

Any update on this? What size/model tire are you running? What kind of mileage long term? Still loving the 4.88s? I'm considering re-gearing and adding a locker.

 

The actual tire has a large effect. It isn't the weight or the size (much) but rather the ability (or inability) of the tire compounds to return energy (spring back) when they deform. This is called hysteresis and generates heat and rolling resistance (Crr).

Unfortunately no one measures this for aftermarket truck tires... or at least no one publishes the results. So lacking important info, we pretend that something we can actually measure (weight) is the cause of poor MPG, and it isn't. True, a tire that has more or denser material in the tread and sidewalls may contribute to rolling resistance, but it isn't a great proxy. A better one is to check the speed rating for tires of the same size and type and load rating. Speed rating is a measure of heat generation at a particular load, pressure, and speed. Higher speed is good. It isn't perfect either, but...

My Hankook ATMs have low rolling resistance. On a particular long trip, about half freeway and half secondary roads with lots of elevation change and not wind aided, I got 17.8 and 17.7mpg. Locally (also lots of climbing and descending) I've gotten even better sometimes. Idling at drive-ups and stoplights will knock that way down, though. They no longer make these tires, and can't vouch for the newer model.

If I had to pick an AT that is likely to have the best Crr, it would be the Wrangler Territories. They are available in 315/70r17 (MT), C load, 35psi max, S speed, 52 lb each.... and 325/65r18 (AT: this size has the same tread as the MT, which means "maximum traction" not "mud terrain"), D load, 50 psi max, T speed, 65 lbs each. They come stock on the Ram TRX and Bronco Sasquatch.

 

Lost ~2 mpg

Before: 17 mpg with stock Michelin

After: 14-15 mpg with Falken Wildpeak AT3W