[TexasCub]

Can anyone who is running these , especially on stock wheels chime in on any affects on you fuel mileage or performance. I know the diesels have a lot of momentum when running down the road but for example the ST Maxx in this size is like 16lb heavier than stock per tire.

 

[hmfman91]

I have the 295/70-18 on a set of aftermarket wheels not stocks and for what its worth I have lost 1mpg. I know you asked about factory wheels but I believe you will still loose about the same amount of mpg.

 

[Quint]

Ive been running them on factory wheels for about 47k miles now (give or take). From what I recall I lost about 1-1.5mpg but to be honest at the time I was going off city driving to figure out my mileage.

My last fuel up (doing mostly freeway with about 2 or so hours in stop and go traffic) netted me 20.7mpg which tied with my best for stock tires and stock emissions. Im sure it would have been better had I not got stuck in traffic so many times for that tank of fuel. If you look at my fuelly I have been averaging 19.5 or so for the last ten tanks of fuel. Alot of that is doing 70-75 with some stop and go and city lights.

My odometer is calibrated for the larger size FYI.

 

[Jimmy N.]

With 3.42s you're already over geared so taller tires aren't going to help the situation.
Also, unsprung weight is ugly by itself, and rotating mass is the worst there is for performance.

If you need 295/70s and can't regear, then you'll just have to live with the results.

 

[Quint]

With 3.42s you're already over geared so taller tires aren't going to help the situation.
Also, unsprung weight is ugly by itself, and rotating mass is the worst there is for performance.

If you need 295/70s and can't regear, then you'll just have to live with the results.

Yeah I didnt notice he has the 68. With my G56 its a non issue, actual does better for overall driving with the bigger tires. With the 68 I would think 373s or 410s would be better when changing tire sizes.

 

[TexasCub]

Yeah I’m pulling the 295’s off on Monday and going back with 275’s. If I lived in flatland it probably wouldn’t be a big deal but living in the mountains in Colorado with constant up and down I don’t like how the truck performs.

 

[TexasCub]

Well I don’t know if anyone even reads this forum , but today I removed the Toyo AT2 Extreme 295/70/18’s and went back with Toyo AT2 275/70/18’s. Easily a 2 mpg difference on the highway and about 3-4 mpg difference in city driving. Glad I had the opportunity to switch back at no cost. Sure the big tires look cooler but there’s a pretty big difference in the acceleration, shifting, and braking by just adding 16 lbs per tire and a little over an inch in height.

 

[Quint]

Well I don’t know if anyone even reads this forum , but today I removed the Toyo AT2 Extreme 295/70/18’s and went back with Toyo AT2 275/70/18’s. Easily a 2 mpg difference on the highway and about 3-4 mpg difference in city driving. Glad I had the opportunity to switch back at no cost. Sure the big tires look cooler but there’s a pretty big difference in the acceleration, shifting, and braking by just adding 16 lbs per tire and a little over an inch in height.

Thats a pretty extreme difference in fuel mileage. Glad I got a manual. Goes to show the autos need gear changes for larger tires since it seems the 3.42s are pushing the limit on gearing.

Cant remember but did you adjust the speedo for each change in tire size?

 

[TexasCub]

No I didn’t mess with the Speedo, according to the gps app on my phone I was 1-2 mph faster than the speedo at like 70 and the stock size is 1mph slower than the speedo. Keep in mind I live in Colorado , my house is at 7200 ft and town is 1200 ft lower than my house, lots of up and down all around mewhich im sure amplifys the fuel mileage.

 

[Jimmy N.]

Well I don’t know if anyone even reads this forum , but today I removed the Toyo AT2 Extreme 295/70/18’s and went back with Toyo AT2 275/70/18’s. Easily a 2 mpg difference on the highway and about 3-4 mpg difference in city driving. Glad I had the opportunity to switch back at no cost. Sure the big tires look cooler but there’s a pretty big difference in the acceleration, shifting, and braking by just adding 16 lbs per tire and a little over an inch in height.

Wish you could spread the good word on other threads. I'm amazed at how many think that even larger tires than stock are a good idea with 3.42 gears.

But, it's been said many times that it's better to look good than to feel good, so practicality and physics gets to take a back seat to the almighty image.

Thanks for posting your findings!

 

[TexasCub]

Yeah I see it everyday, trucks jacked all to hell with giant tires and I KNOW these trucks have to perform for crap, they were never meant to be set up like that. Saw this truck at the local wall mart yesterday and all I kept thinking was a I hope he has a extra fuel tank in the bed!

 

[Rgwinn]

Thanks for taking the time to post these comments. I had been pondering this same question. I too have an 18’ with 3.42 gears so I will keep my stock tire size. I don’t like the Firestone Transforce, so I may look at just replacing those in the near future.

 

[Jimmy N.]

Thanks for taking the time to post these comments. I had been pondering this same question. I too have an 18’ with 3.42 gears so I will keep my stock tire size. I don’t like the Firestone Transforce, so I may look at just replacing those in the near future.

Don't overlook the option of going to a shorter tire. And if getting a set of 17-inch take-off wheels you could create the equivalent of having 3.73 gears.

If so, look for a suitable tire with a 10% lower static loaded radius than your current tires.

 

[TexasCub]

Thanks for taking the time to post these comments. I had been pondering this same question. I too have an 18’ with 3.42 gears so I will keep my stock tire size. I don’t like the Firestone Transforce, so I may look at just replacing those in the near future.

It really is a bummer because these trucks look better with the bigger tires but it really does affect performance and I damn sure didn’t spend as much as I did on this truck just for looks. The crazy part is going up 1” and up in width .8” increases the tire weight by 20+ % I really feel like that’s the biggest factor. Hell braking even felt different , kinda like I was pulling a trailer even though I wasn’t. I don’t understand how guys running even bigger tires without regearing are not seeing and feeling the cons of the bigger tires.

 

[colombia]

I did the same thing with my dually yesterday. I haul for a living a constantly gross around 35k lbs. I took off the 255/80/17 coopers and went with 235/70/18 BFG’s factory size and it makes a world of a difference.

 

[steve05ram360]

It really is a bummer because these trucks look better with the bigger tires but it really does affect performance and I damn sure didn’t spend as much as I did on this truck just for looks. The crazy part is going up 1” and up in width .8” increases the tire weight by 20+ % I really feel like that’s the biggest factor. Hell braking even felt different , kinda like I was pulling a trailer even though I wasn’t. I don’t understand how guys running even bigger tires without regearing are not seeing and feeling the cons of the bigger tires.

General info here... I went from a 30# wheel to a 21.4# wheel with the same tire and gained ~1.5 mpg. Swapped in an AL driveshaft and gained ~0.9 mpg from one week to the next with no other changes to the truck. When I dropped back down to stock height, I gained ~1.0 mpg back... so to sum it up, went from the low 19's up to the mid 22's and possibly 23's by the end of the week with the most current tune change. Last 4 tanks wee 22.6, 22.5, 22.4 and 22.7. Note that there was an e-fan swap (could not measure any difference) and a lot of tuning changes that occurred.

Back when I had a 285-75-17 tire (current is a 285-70-17 tire) I was able to get 21~22 mpg on the hiway fairly easily by keeping speeds ~65ish (Minnisota & Cali). With the current tire & before all the current changes, ~20.X was a great tank. Was never able to really get much more than mid 20.x's for mpg. With that said, I did the math and the next tire going on is 5# heavier than what's coming off (plus whatever wear dropped the weight to at the end). Not sure if I'm going to be able to get back what I lost when I went down a size on the hiway but am going to give it a shot. There is a 60 day return limit on the tires I'm getting into next (not the same as the current one) so I have time to see how they do.

The tire swap is coming up in the next 4~6 weeks... This is on a 3rd gen G56 4wd truck...

 

[RD66]

Been reading up on the tire size/weight debate and have a quick question. Which is gonna be more detrimental to the MPG's...height or weight?

Want to go from crappy stock 275/70/18 tires to Falken Wildpeak AT3W 295/70/18 AT tires. There's a 1.1" height increase and 18 lb/tire weight increase over stock tires. I realize this is double whammy and know MPG's will suffer more. The stock Firestone HT's are very, very light tires at only 50 lbs each and bear in mind any E-rated AT tire is in the 56- 62 lb range at same metrics.

That being said if I just stay at stock size but increase the weight per tire by 10-11 lbs with AT tires how greatly will it affect the MPGs?

Thanks

 

[Deerhunter4]

Been reading up on the tire size/weight debate and have a quick question. Which is gonna be more detrimental to the MPG's...height or weight?



Want to go from crappy stock 275/70/18 tires to Falken Wildpeak AT3W 295/70/18 AT tires. There's a 1.1" height increase and 18 lb/tire weight increase over stock tires. I realize this is double whammy and know MPG's will suffer more. The stock Firestone HT's are very, very light tires at only 50 lbs each and bear in mind any E-rated AT tire is in the 56- 62 lb range at same metrics.



That being said if I just stay at stock size but increase the weight per tire by 10-11 lbs with AT tires how greatly will it affect the MPGs?



Thanks

I went from 275/70/18 trans force HTs to Nitto ridge grapplers of the same size. I think the nittos weigh about 60 lbs. I lost about 1-1.5 mpg on average. Had 7k miles on the HTs and now have 12k on the nittos so it’s a fair amount of data with each. Weight and tread design both contribute to the decrease.


Sent from my iPhone using Tapatalk

 

[RD66]

I'm having 295/70R18 Cooper AT3 XLTs put on as I type this. Went back and forth between keeping stock size or going larger and just felt the truck needs slightly larger tires to sit perfectly. I may lose 1.5 MPG, but I think it'll worth it.

 

[steve05ram360]

FWIW, I jumped up 1" in height, 5# per tire and lost (last time I checked...) 1.4 mpg. Currently working on the tune to see if I can get any of that back. Speedo corrected from day one of the tire install.

I lost the ability (going from a 33" tire to a 34" tire) to coast downhill on several of the "flatter" hills I encounter on the way to work. The steeper ones have my speed dropping approx 1~2 mph over what it was. Bear in mind this is going from a worn 33" to a new 34" so I'd expect some drag. Throttle response was noticeably different with the taller tire.