How much does tire weight really affect performance/mpg?

It will make a difference. The problem with adding weight is it hurts acceleration, braking, ride quality, and mileage. When I reduced 5 pounds per wheel on my sports car the responsiveness at speeds below 40 was huge and the traction control/abs reacted a lot quicker. Avoid adding weight on the wheels/tires if you don’t really need to

 

FWIW. When I went from stock to 265/75/16 Duratracs I could feel a small loss in performance and mpg. When I switched from my 45 lb Duratracs to my Coopers I shed 6 lbs per tire. I noticed very very little performance or fuel mpg gain. I believe size plays way more of a factor in the amount of perceived power loss than weight.

 

LoL every where you go, youre wrong. never has a poster been more wrong in the history of technical-info posting
and Every thread on Tacomaworld™ is a duplicate of 10 others:

MASSIVE impact of Unsprung/rotating weight upon Energy conversion
gross increases in unsprung weight directly inhibit the drive-trains ability to convert the available power to wheel-HP hitting the ground.
-The motor must work 3x harder to move each UNSPRUNG LB compared to a sprung LB.
-Exclusively increasing unsprung weight by ~50% per wheel, per corner, "in layman's terms" reduces the motors wheel/HP output (via drivetrain effeciency conversion-loss not mechanical)to a proportion where power-conversion loss is mathematically similar to a reduction in mechanical HP anwhere from 1/2lb-1lb per unsprung 1lb.

Thus going from an OEM setup:
-265/70/16 Goodyear Kevlar @42lbs
-on TRD-OR wheel @25lbs
Would =~67lbs of unsprung weight per corner
-Toyota Factory rated this set-up at:278hp 265tq
to*hypothetical EXAMPLE*
-285/75/16 BFko2 E-rated @59lbs
-Method 16x8s @ ~25lbs
-would = 84lbs of unsprung rotating weight per corner
-DELTA (change) value= 17lbs+ increase over OEM per wheel, per corner
The equivalent drive-train loss in efficient conversion of available engine-power to wheel-HP would mathematically reflect the output of a 244HP motor
Therefore simply switching from OEM tires, to E-rated 285 Ko2's would perform as if the truck LOST ~34HP
HOW?WHY?Where did you get those numbers?SHOW YOUR WORK:
Lets say you went conservative with the measure and said each unsprung pound. increased resulted in a drivetrain loss of efficiency= to 1/2hp per unsprung pound gained
-"Delta" = 17lbs of unsprung weight gained.
-84lbs(new)-67lbs(oem)= 17 (unsprung lb. increase)
-17(unsprung weight increase)x.5(the LOSS of hp due to increse in-efficiency)@(1/2hp loss per lb.+)= 8.5
-8.5(the equivalent HP loss from drivetrain ineffiency)x4 (the number of wheels)= 34
so increasing to 285/75/16 E-Rated K02's will have a drive-line power-conversion detriment as if ~34 HP was taken off the truck. Thats being conservative.
NEW HP of ~244hp useable, convertable power after loss.

I hope the numbers and facts begin to sink in

 

Explain what you mean by "HP""Potential Energy" and "Efficiency of conversion of energy to move mass" and show your work:
Everything is calculated off of "Crank Horsepower" because "wheel horse power" is an abstraction, rather than a "real" number.
-This is why manufacturers typically dont use it.
-A dyno measures "WHP" by a given vehicles ability to spin a drum. The computer is pre-programmed to interpret the drum RPMS as "WHP"
-this is why different dyno's produce different numbers for the same vehicle.
-thus WHP is an abstract number that isnt used for math here
-however, valid is your 20% drivetrain loss concern.

The type of "energy" this refers to is a physics term called 'potential energy'
-(which can exceed 278hp)(the motor has potential to perform better than the measured value the factory quotes)
-I will try to use "taxes" as an analogy to articulate a complex idea lol

what about the 20% drive-train loss?
-you simply multiply your final HP number after the equation I used by .2
Why?
Because your assuming that even though you may have just recovered or lost additional efficiency in turning POTENTIAL energy into a mass mover -- The result of eliminating or adding unsprung mass -- that this was a"pre-tax" gain, and your "20%drive-line loss estimate" is tax your drive train is paying (lol to the diff) no matter what:
-in both the case where efficiency increases, as well as where it decreases the diff is still going to consume a portion of this power when it does ITS translation of potential energy.
-the Wheels are the Only thing the motor is truly "driving". The motor connects to drive shafts, that connect to the diffs, that connect to the axls that connect to the wheels.
-this then essentially puts The mass of the wheels in direct relation to the motor ability to convert potential energy (which can exceed 278hp) to Crank HP
heres where "potential energy" finishes us off:
-because you lightened the bodies of mass directly connected to the motor itself (through an elaborate tax-system of shafts and diffs) the motor has accrued performance characteristics of a motor with additional(or less) HP.
Essentially it is converting potential energy at the rate a motor with the new performance stats would convert.


This is the most confoundingly difficult idea to articulate ever.
Race teams, engineers and Corporations pay people millions to figure this shit out.
and If I was able to articulate it any better than this LOL i would be one of those people. Its that hard.

hope any of this helped

 

I'm not sure that lack of concern is age exclusive.

You don't have to be old to have disposable income.

And not everyone old had good life situations or prepared well for their golden years.

However, boasting comes in all shapes and sizes. Mostly from 'little' people. And not little in stature.

 

Maybe he wasn’t boasting and the comment was completely exclusive of his income. Some drive their truck in the configuration and style regardless of how it effects gas mileage. Maybe he was simply stating the truck gets what it gets and there’s no point in looking at the price of gas or stressing about it because it’s a necessary evil and your stuck paying for it either way.

I personally look at it when I fill up, and try to stop at a station with better prices. But in the end whether it was $60 or $65 to fill up, or if I got 280 or 300 miles out of the tank, I just shrug and move on. Because it’s not like I’m going to stop buying gas and stop driving my truck.

 

Of course you could be right.

Or not.

Just reads like he's better than those who care about MPG.

My apologies to him if I'm wrong.

 

I'm not saying I don't believe you, but... I don't believe you.(or your math was wrong)

 

Not sure if he was boasting or not, but threads like these make me laugh. Said person buys a truck that already has questionable mileage then said person goes and loads it up with gear and bigger tires and then complains about mpgs. I just don't get it, Or maybe im also one of those people that don't look at the price of gas cause well if I cared I would of bought a prius.

 

I was on a 300+ mile road trip on a family vacation and I made it a point to check my MPG. I filled up once when we left, started the gps, filled up at a quarter tank and the truck computer said I was averaging 15.x MPG but I did the math and I actually averaged 16.x MPG

 

Just another data point:. I went from stock to 265/75r16 and definitely noticed the truck was more sluggish off the line with load C Duratracs (3lb increase per tire). Lost 0.5-1mpg in 50:50 city:highway. Switch from stock wheels to SCS to F5s. h say if I gained much mpg (it's been so much colder lately). Maybe gained a 0.25-0.5 mpg overall. I think I'd have gained more but the truck is just much lighter on its feet now and I think I'm hitting the pedal harder because of it. Definitely noticed the 7 lb drop per wheel though.

 

Lol. I don’t know either. The guy could be a complete asshole.

 

The stock version of the Goodyear’s are only 35 lbs, so you gained 10lbs with the Duratracs.

 

I had to search for it but I've seen the goodyears in that size listed at 42 lbs as well on tire rack. Now I see the Toyota OE style listed at 37 lbs on discount tire. Now I'm curious so I'll have to measure my old spare

 

Im confused about this as well...

12/32 @ 42lbs

11/32 @ 35lbs..

I find it almost possible to believe 1/32 of an inch on a tire or white lettering is responsible for a massive 7lb difference..

 

It’s .4” narrower too. Probably lighter weight plys too if I had to guess.

 

The Canadian-made is the OE tire.
The OE sidewall is ridiculously thin.

 

I think part of the problem is that Toyota designed the Tacoma around a set of ridiculously light "all-terrain" tires. These Wrangler Kevlar tires that come stock are only 37 pounds which is easily the lightest Offroad tire you can find. This just makes the Tacoma's already mediocre engine look even weaker because the horsepower & torque specs are based on the assumption of using flimsy, weaksauce tires that nobody would use if they had a choice.
Don't feel guilty about getting meatier tires that weigh more. As the owner of an offroad-capable truck, you are just doing what any normal Offroad truck driver would do. If your truck is slower as a result of getting heavier tires, don't feel guilty about it. It's not your fault. It's Toyota's fault for setting unrealistic expectations for an underpowered engine.
The 278 hp/265 torque numbers are misleading because they assume that you are using lightest Offroad tires that one can buy. This is not realistic for a truck as capable as the Tacoma. You deserve good, tough tires.

 

I went from 265/70R16 BFG AT's @ 56#/tire to 265/70R16 Michelin Defender LTX @ 38#/tire. That's 18 pounds per tire and a total of 72 pounds less rotating mass. It made next to no difference in MPG. It did improve the ride and tire noise though.

 

Any additional weigh of each tire will effect many things , hp, mileage,etc..as mention by many of the above comments..
Rumors has it ..For every hundreds pounds you remove from your vehicles...will save gas ( one mile per gallon)..approx. ..aero dymamics...is also a huge factor..that kills mileage..

if adding heavy tires...remove something from the vehicle of equal weight..? Not sure this will work..
Most of us are NOT racing...we want to make our trucks more effected for our travels off roading..
If concern of just tires weights...and less gas mileage..carry a bigger gas can( plastic )..lol

when overland and camping..no one wants to leave the food home? Can corn ,can beans,can soups..um how much does this weight...if I leave home..will I get better mileage?

Fiber glass hoods ,fiber glass fenders...etc..
Ever go boating ...weight is a huge factor too...of what you carry on board....but there are things you will always want to have..safety equipment, food ,water,gas ,ice,coolers,rods and reels, etc..oh

Beer ... 12oz can -24 pack=20 lbs, 12oz bottle beer=36lbs...maybe leave the beer home or buy diet soda(?)..lol
Aloha
Aloha