Freewill

Extra weight will cost some MPG, whether it is sprung or unsprung. Unsprung weight will also change the handling, but this thread is about MPG. The MPG penalty for extra weight comes mainly when accelerating. Because the tires must "spin up" during acceleration, the weight penalty may be a little greater if the extra weight is in the tires.

Running at a steady speed, the tire MPG penalty comes from tread design and width. A narrow slick gets the best steady speed MPG. The more open, wide, and aggressive the tread, the more rolling resistance the tire has. Rolling resistance costs fuel as shown here over and over when tires are swapped between "highway" tires and mudders.

Now for a trip into left field: I don't have any data to support this, but I have a theory that louder tires have more rolling resistance. When you can hear a rig coming 3 blocks away, consider how big a sound system it would take to create that sound. How ever many watts the sound system would consume is how many extra watts the engine must produce to keep those tires rolling. Nittro tires claim to have the quietest tire for a given tread design. Does anybody know if Nittros get better MPG?

sam187st

in one of the posts in the thread some has claimed to have lost only 2.5 mpg with 325 65 r18 nitto's, and that way less than i lost with a bigger tire than i have, so there maybe some truth to this, but that can all change once the tire wear starts kicking in. when my mickey mtz were new, they were very quiet, but now they love screaming!

also if there the mud grapplers i know they are way heavier than mine. i think the 33 mud grapplers are in the 70lbs area, just the tire

WXman

This topic is very interesting to me, and I've studied it with real world testing on a few different 4x4s extensively over the past 5 years.

First of all, let me say that MPGs = money. The average person drives almost 1,500 miles per month these days. Gasoline is currently running around $3.25/gallon. That means that simply going from 18 MPG to 16 MPG is worth $33.75 per month! Just 2 measley miles per gallon is all it takes to really start hitting you in the wallet. If you drop 3 or 4 MPGs from adding heavy tires/wheels, you could be taking a $50 bucks per month hit easily. That's bill-paying cash guys. That's toys for your JK cash. That's taking the wife out to eat cash. You don't want to waste it on gasoline.

With that said, the stock 16" steel wheels weigh 25 lbs. The stock 225/75-16 tires weigh 27 lbs. That's 52 lbs. per corner. I was getting 19 MPGs consistently in mixed city/highway driving with that combo.

Then I simply added 31" tires...and those weighed 37 lbs. So I added 10 lbs. per corner. I dropped to 17.5 MPGs instantly.

Then I added 16" alloys that weigh 20 lbs. each and 33" tires that weigh 55 lbs. so now I'm at 75 lbs. per corner. My mileage is in the 16 MPG range.

I lost 3 MPGs just from my wheel/tire combo alone.

Keep in mind that stock Sahara wheels/tires are tipping the scales at 73 lbs. per corner. So STOCK JKs will all see different MPGs based on how they leave the factory.

With 33" tires, it's a triple-wammy. You're adding weight. You're adding leverage against the drivetrain because of the added diameter. You're adding rolling resistence because of the added width. And, you may be adding rolling resistence because of the more aggressive tread. You're also adding wind drag because of the width outside the fenders. So.... every possible thing you can do to decrease efficiency is being done simply because of your bigger tires.

Sure, they look awesome. But they cost money every time you turn the key. This is why a lot of guys are starting to consider... do I NEED 35s just to hit the trail 6 times a year?

There are tall, skinnies like 255/85-16s which will fit the stock 16" wheels and that may help some. But... by far the best thing you can do is stick with ALLOY wheels in the 15 or 16 inch range. Then wrap them in 32s or 33s that are listed at 50ish lbs. This will keep you in factory specs. in terms of weight...and will get you around on the trail just fine. It's the best compromise to keep your wallet from getting drained.

f2fast4u

Surprisingly smooth as glass. I have cast aluminum rims plus those Nitto's only weigh 71 pounds. I cruise 80-85 on the Interstate all day long. I really like this tire/wheel combination. 32 psi all around.

tlend

I went from sahara wheels and tires to AEV pintlers and nitto terra grapplers in an 285-70-17. I noticed an immediate difference. The best I can get on the highway is about 17.5 with an unlimited auto. Around town is even worse. And that's driving good.

db09JKU

I lost about 2mpg going from the stock SRA's to 285/70-17 Treadwright Wardens. Stock wheels. The SRA's weigh about 36 lbs and the treadrights 65lbs.

Otbiker

Went to 265/70/17 Michelins on the stock alloys. No change in mileage.

reddragon

So how much do the stock 17s weigh?

sam187st

only 71 lbs? the i about to pull the trigger on some bfg At in 35x12 r15 the tires are 54 lbs. that alone is 17 lbs difference.