Larger circumference tires better mileage?

Grit dog wrote:
My strong preference would be easy vs difficult or costly to arrive at the same solution.

Me too, but it isn't the "same" solution or same set of problems/fixes which was my point. In my case, I could go slightly higher, but the cost of 6 tires vs the gear change would be a few hundred dollars different. It also wouldn't change the gearing as much as a gear change.

For those who might want to read more about someone doing a swap on a '06 from 3.73 to 3.42, here's a thread. http://www.cumminsforum.com/forum/3rd-gen-powertrain/385747-3-42-gear-swap-questions.html Obviously cheaper if you only did the rear and was a 2 wheel drive. The OP implied changing rear only in his first post.

Somewhere on this forum you should find old thread where 1 of the members, who drove dually in his bussines - decided to convert it to SRW as he had no more use for dually and did not want to buy new truck.
He did not go cheap and spend some serious money on new adapters and other stuff, but come back reporting huge mpg increase.
I could not believe such big difference was possible, as I don't complain about dually mpg (beside old GMC with 454 carburated engine making 5-6 mpg)
but the guy did not buy the "mpg is what it is" mentality and went for it, winning big in the result.
There is a risk in everything.

^Sure, gear ratio change is a solution, an expensive one. So is driving slower or putting up with 2700rpms down the freeway.
Without tearing the truck apart, taller tires satisfy the request for lower rpms and are almost a "free" upgrade. (In that if you need tires, taller cost only marginally more than shorter)
That was my point. My strong preference would be easy vs difficult or costly to arrive at the same solution.

Grit dog wrote:
Your truck with 4.10s NEEDS the tallest tires you can fit on it for your intended use and sane engine rpms at freeway speeds.

Or, just change the gears as has been noted and don't raise the center of gravity, have fitment including spare tire issues, and don't change your braking characteristics. BTW, I have only 2 pages. Must be your setting for how many posts to show per page.

Bottom line, the 4 pages of mpg discussion and someone's experience towing bulldozers is mostly irrelevant.
Your truck with 4.10s NEEDS the tallest tires you can fit on it for your intended use and sane engine rpms at freeway speeds. My truck with 3.73s and a shallower OD ratio is still screaming at anything 80 mph or faster.

joe&julie81 wrote:
BTW, the TC I'm going to is a NorthStar 950sc, and it just rolled out of production today in IA. So it will be a low profile pop-up. Looking forward to taking delivery on it sometime in the next two weeks.

Good choice. Northstar (Willett) builds a nice wood framed unit and would have been my other choice other than the Palomino. I got a killer deal on the Palomino so I bought it.

How did you option it, if you did.

Hard to beat a pop up for going down the road at speed. Little forward wind resistance and almost no side buffeting either, plus they are easy to store. Get yourself a used single axle boat trailer, remove the bunks, set the camper on the frame rails and roll it in your garage in the off season. That way it's out of the elements and will last for a long, long time. What I do. Mine 'sleeps' in the garage next to my truck all winter. It's there right now.

Hardsides are a pizzer to store inside unless you have a commercial building with a high door. The alternative is a camper cover but it's still outside. TC's last a whole lot longer stored inside.

On the road, I don't even know mine is in the bed unless I look in the mirrors.

The big positive for me is the offroad factor. 95% of my camping is off road via unimproved seasonal roads so it's imperative that the camper I have has the lowest possible vertical Cg and that mandates a pop up. Hardsides with heavier appliances mounted high up inside (microwaves, fridges, slides, ac units, etc) all contribute to a high vertical Cg and impart a rocking effect not only going down the road but especially off road on off camber surfaces. None of that is inherent with a pop up because the heavier appliances are all mounted low in the unit, plus the roof telescopes down, lowering the vertical Cg even more.

I think you'll like it just fine and I see all the Northstar pop ups now come with the Reico-Titan electric roof lift. It's on my Palomino and it's fantastic. You turn on the roof mounted vent fan, lower the tent and the fan keeps the tent sucked in so lowering is a one person, 15 second job.

MPG is always a factor unless you drive Royce-Rolls or Lamborghini.
I never had same trucks with different differential, but I had 2 truck with the same 7.3 Powerstroke which were 2000 F250 and 1999 F450
F450 was dually, but F250 was 4WD, what should about equal rolling resistance. Both of them were flatbeds although F450 bigger one and F450 was over 2000lb heavier, so those things combined with different differentials made about 60% mpg difference when empty.
Not good comparison, but I was using both for hauling 15,000 lb bulldozers, so with big trailer behind -truck aerodynamics didn't mean much, while weight difference between 27k set and 29 k set is marginal.
So the only main difference in those setups was differentials (I don't remember the exact ratios, but difference was big)
Will add that F250 with low differential was pulling 27k lb set on most of the grades without downshifting.
So did they burn about the same with the same engine?
wait for it.... the lower differential was still giving about 30% fuel savings.

SidecarFlip wrote:

Dennis12 wrote:
Old-Biscuit, This will be the first time i think that i have disagreed with you. The more radius on the tire, means longer to spin and will slow your speedometer and increase your gas mileage.

Dennis... all the above except increase your fuel mileage. MPG is dependent on other factors, not the tire diameter.

Actually my post was about going to 19.5" wheels/tires for increased Tire Load Ratings vs those 17" 'E' tires due to OP getting a TC

MPG is what it is and should not be a big factor.

BTW, the TC I'm going to is a NorthStar 950sc, and it just rolled out of production today in IA. So it will be a low profile pop-up. Looking forward to taking delivery on it sometime in the next two weeks.

It takes X amount of horsepower to send a vehicle down the road. If you increase the resistance by raising the truck with bigger tires, it will take just a bit more horsepower to send that truck down the road.

Every bit of horsepower is used, and it does not really matter much which gear or RPM the truck is in unless it is out of it's power range, the engine will produce the horsepower to power the truck at the speed you want to go.

Putting bigger tires on will lower your RPM a bit, but your foot on the gas pedal will make the engine produce the horsepower necessary to fit the RPM of the engine. If your engine can't produce the horsepower at the lower RPM it will shift down.

With the proper sized tires, you might have a five speed transmission that helps to keep the RPM in the right power range for each speed. If you use larger diameter tires, your transmission range will increase in each speed, and your optimal range of each speed per gear will get larger, and you will likely get lower mileage per gallon as a result. Very marginally, but that is my opinion.