This seems really low, what do you all think? (yet another mpg thread)

I'm sure lifting the truck hurt the mpg.

But the rake was there for more than looks I'm willing to bet.
I didn't think much of it at the time when considering my lift and felt moderate lift would be less mpg loss.
As it sits, I might as well have gone with a 6+ lift (felt I really wanted this anyway) as they all seem to lose about the same mpg.

We need a Toyota engineer (yea good luck lol) or some other airflow engineer to give us some real information on how important the rake is and what it effects.

I am sure rolling resistance and diameter play some small part, but I can't believe less weight had no effect, that's simply illogical.
Are you really sure you saw no change, and do you know how much difference in weight?

It should absolutely have a significant effect.
I have seen it in RC cars.
Larger heavier tires shorten battery life under the same driving conditions.
Race car designers/builders take this into account for fuel calculations.
Drag cars, especially the rails with tiny front wheels, less weight.
Lighter cars are faster cars, everyone who races knows this.
Lighter is easier to move, using less energy to move the object.
It's all the same physics.

The question is, how much does the rotating mass weight effect energy requirements to propel the object.

I think your issue is more the width, vs the diameter having an effect.
That is why I specifically stayed with stock width (well that and clearance concerns on stock 20" wheels lol)
More width will add to wind resistance and rolling resistance (I think).
I don't know how diameter effects rolling or wind resistance, but more surface area with increased width for sure makes a big difference.

It really is a total picture of things working together to produce a certain outcome.
Rake, wheel/tire rotating weight, tire wind resistance, rolling resistance....who knows what else....

I am just trying to isolate what has the most effect, and see how I can change my setup to gain some back or even counteract if possible, somehow.

 

You may be on to something here.

I have used both stock 0W20 oil and 5W30 oil no noticeble change in mpg.
Old stock type tires about 35psi.
New E load Falkens at about 44psi.

Strictly 87 octane fuel.
Several brands but I have not noticed or focused on if any brand made a real difference.

Pretty sure I need to change all the diffs, trans/transfer.
Don't recall any of them being done on records at Toyota dealer so maybe original.

I actually gave yall bad info.
I confused the plugs I replaced.
I had a 2011 Limited 4Runner in white for 1 year and I changed the plugs on it as it was 100k miles.
I have and juts looked at those.

I have NOT changed my Tundra's plugs, I think? lol.

I will have to put this top of my todo after the front brakes and spacers.
I will get pics of them and note which came from which cylinder.

Maybe that little vibration I have at idle is really something after all.
But I would think I would get a CEL for a dead or weak cylinder, right?


Maybe there is something here, maybe.......


I put on Falken Wildpeak A/T3W 275/65R20 E load tires.
Falken's website shows 66.1lbs.
WILDPEAK A/T3W TIRE | Falken Tire

My truck came to me as the 2nd owner from Carmax with brand new 275/55/R20 Yoko Geo AT's.
52.3lbs.
GEOLANDAR® A/T G015 | Yokohama Tire
I was already below average mpg at this time.

Stock the truck comes with Bridgestones? Dueller Alenza's was it or does anyone know?
These show 41.6lbs.
Dueler HL Alenza | Truck Tire with Quiet, Smooth RideDueler HL ALENZA (bridgestonetire.com)

So, I have now increased my tire weight by 24.5lbs.

24.5lbs more rotating mass, per wheel, even per driven wheel.
Plus:
Whatever increase in rolling resistance,
And wind resistance,
And I had to remove the front bumper mudflaps (wind resistance again?)

We need someone to make various sizes of larger, offroad treaded tires, using some new technology to drastically reduce weight.
Or we need the same done with wheels.

I know I have seen on the interwebs some plastic wheels, or flexible wheels, airless tires.
Some new future tech, years ago.
Someone has to have perfected this by now, right?

We need the rubber tread patterns/materials of today to hold onto another material under high stress weight/loads/temps without separating, that weighs a lot less.
Also being airless wouldn't hurt.


This tire change loss's plus the lift aerodynamics, and rake aerodynamics are where we lose mpg to get the looks and/or functionality we want.

Now let's attack how to mitigate, or even counteract these effects.

We got smart people in this world, and even this website.

Ima' go google some future wheel designs for now.

 

I come from a family that often owned boats.

You got that right, land mpg beats water mpg no contest.

Boat mpg is seriously awful.
That's why big ships are diesel, best they can get.

My vote for the main use of electric propulsion is in watercraft, not land or air vehicles, yet.

 

I agree with all this.

idling eats my gas.
I use remote start sparingly lately because of this, usually as I am walking up to the truck only lol.

Traffic idling sucks also for sure.

Cold weather/winter fuel is hurting me.
Should improve some in summer.

I have not taken into account the 34.1 tire diameter, but it won't be enough to put me back in reasonable numbers, I don't think.

Does the Tundra not understand the revolutions changed electronically?

 

I need to look into this more.

I really think this hasn't been done due to rubber/oil/tire company monopolies.
Better tech is probly way cheaper and would destroy their businesses.

 

That's what I am saying.

I think I made a terrible mistake on these tires.

And maybe I have some gremlins in my engine.

Maybe.

 

Ok check this out from a quick google of airless tires.
Airless Tires (bridgestonetire.com)

From the article:

"REDUCED CO2 EMISSIONS
About 90% of energy loss from tire rolling resistance comes from repeated changes in the shape of the tries as they roll. By simplifying the structure of the tire, Bridgestone was able to minimize the energy loss in these “air free concept tires.” As a result, these tires have the same level of low rolling resistance as Bridgestone pneumatic fuel efficient Ecopia tires, contributing to reductions in CO2 emissions."

Is it really all about the rolling resistance?
Does that take everything into account in 1 measurement?
Like weight and aerodynamics?

Then my 20" tire should flex less than an 18" tire of the same size.
But my larger sidewall Falkens would flex much more than the thinner stock 275/55 tire.

Let's get these new tires in production already.

What's the hold up, if it works, it works, and it looks to me like it works.

 

Ok I was wrong.
Review of Airless Tires for Cars and Trucks - No Air Tires AZ | Valley Chevy

They claim these new designs are:

• Heavy
• Slow
• Traps heat
• Less comfortable
• Inadequate suspension
• Can be damaged
• Lacks versatility

So, they are actually a step backwards it seems, with current technology.

Or this is misinformation.....

I did not consider the ride quality, presure changes needed (I drive on the beach aired down for vacations), or the weight being higher.
Or heat transfer.

We need something outside the box.
Soft, yet grippy, with low rolling resistance, and low weight.

Sounds like I need to just find the lightest standard combo in my preferred sizes and go drive!

Until something truly better is invented

 

Thanks for joining me on this thought exorcise everyone

There is always more to learn, mpg is complicated, but I think we can fight back some with certain choices and good discussions

 

Nope...

 

I have a 6" lift, heavy front bumper, camper shell and run 35-12.50-20's. I average about 11.6 around town and 12.6 on the hwy running about 75-80. I have seen my mpg drop into single digits when I drive like a douche. lol...

 

https://ecomodder.com/forum/EM-hypermiling-driving-tips-ecodriving.php

https://ecomodder.com/forum/fuel-economy-mpg-modifications.php

 

100% sure my mpg is dead nuts the same with lighter tires of the same size. I went from 54 to 42lb tires if my memory recalls.

im sure a larger change would have shown different results, however i have a feeling rotating mass is a far less % of the problem than aerodynamics/mechanical dis-advantage of taller tires

 

The lift should be more of a detriment at high speed, but not so much at low speeds. I'd expect Falkens to be one of the better tires for rolling resistance, because they tend to have a high speed rating. Speed ratings are limited by heat and temperature primarily, and low heat generation means low rolling resistance. It's far from perfect, but a better proxy than weight.

I have Hankook ATMs and I know they are good. On another forum I mentioned that my big fat ATs got better MPG than my stock tires in town, and someone else correctly identified the brand and model because he'd had the same experience! Weight nearly doubled, width went from 255 to 325, and diameter from 32 to 34.6. They no longer make them, but the AT2 is probably similar.

If they are using the term properly, rolling resistance is basically internal frictional losses caused by distortion. It doesn't include aero losses or weight. Tire weight is actually a minor factor and not nearly as important as most people believe. Most heavy tires have poor rolling resistance, but it's because they also tend to have thicker tread and casings, which tend to increase rolling resistance. Plus if you are doing a bunch of rapid accelerations, the weight will be detrimental to MPG (more momentum to move). Wider tires and lower profile tires tend to have less rolling resistance (all else being equal) not more.

There are a bunch of different factors, but the most important one when comparing tires with similar size, specs, and purpose is the properties of the compounds the manufacturer uses for their tread and casing. If the rubber springs back from distortion with minimal heat generation, then rolling resistance will be low. This behavior might be good for MPG, but there are many other factors to consider, like traction, durability, tread life, etc. Unfortunately for truck tire buyers, rolling resistance is pretty much never tested.

 

Those are good websites with good info.

I was just hoping we didn't have to go to those extremes.

Trying to have Some cake and eat it some of it too lol.

 

You may be right.

But I'm sure rotating weight plays a part.
I have seen it and all racers do it.

Maybe it's a small part after all.

 

Yep. Sounds right

 

Ok so no one bought a Tundra for gas mileage! You have a lift and big tires, what do you think would happen! Just think about the money you are saving by not having to take it in for stupid parts breaking and maintaining it! Everyone wants better gas mileage, I get it, but I will take reliability any day over gas mileage. It sounds like you have an awesome rig! Enjoy it and don’t worry about mileage. Just my 2 cents! Sorry I have been drinking, but really be happy you don’t own a Ford/ Chevy / dodge and have to take it into the shop all the time. I have plenty of friends who seems to live at the dealer getting their trucks fixed. Sometimes I even forget what my engine looks like, then I open the hood and say oh ya!!!! Glad I bought a Toyota! Change the oil and good for another six months! Ya I don’t drive it far, but it is the best truck I have ever had! Enjoy it and have fun! My time is worth more than mpg’s any day! Sorry for pointing out the obvious! Have a great day all!

 

Thank you for your contribution!

Yes I agree, lift is probably more a factor at speed.

That's crazy about your tires!

That seems counter intuitive about wider tires.
More surface area should be more friction, not less?
I get the low profile being better as they are stiffer and flex less.

Tire construction and materials all have effect also, good points.

Sounds like we need truck tires, and all tires, to work on and promote their rolling resistance figures.

Save the planet types should be all over this.
Less rolling resistance is less fuel.

We at least deserve to know where each tire stands.

I wonder if I air up from 44psi to something higher?
I will get less rolling resistance more mpg back?
But I read this is about the spot I should be in for psi on these tires based on load rating vs tread life for a truck of this weight.

I wanna say I read that on here from a Falken rep post about psi on E rated tires for our trucks that don't require E rated tires.

I don't want to shorten tread life a bunch either, and the ride will get worse with more psi.

Trade offs.....

 

You are right for sure.
I also knew I was gonna take a hit.

I also am a toyota family for life for all the obvious reasons.

I have a 300k 4runner for a reason lol.

I just feel I lost more than expected (or what seems normal based on others results here) with my setup.

I think I'm done discussing the tires and lift effect.
We have really gotten to the bottom of that I feel like.

I need to look into my plugs and wires and see if something is off there maybe.

Thanks and rock on

 

Hey seafury no worries! Not trying to bring anyone down. At this point I don’t think plugs and wires will really matter all that much. That is awesome about the 4Runner going 300k, congrats! Didn’t keep mine that long, but I am sure it could reach 300k if I kept it! I wouldn’t bother with plugs or wires unless you are close to 100k. Maybe headers? Don’t know if you will ever hit the mpgs your thinking about. My parents had an ‘03 4Runner that had more power and better mpg’s then my ‘03 4 runner. Don’t know if it was a factory freak or not but after a bit I didn’t worry about it. It is what it is, and I still loved my 4Runner until I sold it to my parent and then it got passed down to my father in law. The only thing you can probably expect a decent return on is headers. But for the price I would stay with what u have and pay the little extra in gas and enjoy! Cheers!

 

A wider tire will have a shorter and wider contact patch, which reduces tire distortion.

The thing about E rated tires is they aren't recommended to have <35 psi, even though their capacity at that psi is way beyond the weight of a Tundra. I put 38 psi in my front tires, and 32 psi in the rears with no load. On a smooth road you would get better MPG with high psi (rolling resistance will be lower) but when bumps are in the mix, this isn't necessarily the case... the shock from the bumps creates another loss, which might be higher than what you saved from less casing distortion!

Extra info here: https://www.toyotires.com/media/3729/application_of_load_inflation_tables_20200723.pdf

and here: At 35psi your tires are rated for 2080 lbs each. You probably have ~1700 lbs on front tires, and 1200 on rears with no extra load.

 

I’m on about the same setup, 35” ridge grapplers and I’m doing 10-11 in town and 12-13 highway maaaaaaybe.

 

I recently took a trip, filled up, hit the back roads headed to Houston, and was running 75-85mph most of the way (speed limit 75 once into tx) went through some really small towns, but hand calculated 13.7mpg.

295/70r18 tires (34.5in tall, 11.7in wide)
3.25in of lift in front, 2.1in back
Roughly 350-400lbs of weight between the bumper, winch, and skids.

This is the best mileage I've gotten since the lift and tires. Around town I'm at 10mpg or so. I'm sure if I baby it I can get to 14 or 14.5. It's all flat where I live. And warm.

 

Similar setup as me except I dont carry any weight in mine driving daily. Around town im getting about 12.8. Did 13.8 with about 75% highway driving. I add about 6% to mileage when hand calculating due to difference in odo with larger tires.