2nd Gen Non-Engine/Transmission Do Taller/Narrower Tires=Better Fuel Mileage?

[RHestand]

I've seen this discussed on here before, but I can't remember what the consensus was.

I have 4. 10 gears in my 98 12V 3500 dually, and I would like to drop my RPM as much as possible for freeway driving. For most of my driving I don't pull my 31'/8000 lb camping trailer.

I put taller/wider( H-2 wheels with 315s) tires on my 06 2500,(with 3. 73 gears) and the fuel mileage stayed the same.

With new taller tires I would like to think I might improve my fuel mileage also. I usually drive empty, at about 65MPH.

So what do guys think, and what is the tallest size tire that would fit on my stock height truck with stock 16" wheels.

TIA, Ray

 

[LBARTLETT]

my understanding is the sweet spot is about 1,800 rpm, my belief is a taller/narrow tire improves mileage but a with a taller/wider tire what is gained with the height is lost with the width (more road surface), if you find anything taller than a 235/85R/16 for your dually let me know (although I just bought new Toyo HT's in that size)



I'd love to have taller without the width as I don't want to put spacers on my dually

 

[RHestand]

my understanding is the sweet spot is about 1,800 rpm, my belief is a taller/narrow tire improves mileage but a with a taller/wider tire what is gained with the height is lost with the width (more road surface), if you find anything taller than a 235/85R/16 for your dually let me know (although I just bought new Toyo HT's in that size)



I'd love to have taller without the width as I don't want to put spacers on my dually

Do you know what the installed (or not installed) height for the 235/85/R16 is?

 

[LBARTLETT]

most of them are 31. 5 to 32 inches depending on the brand, what size do you have on your truck?

 

[RHestand]

most of them are 31. 5 to 32 inches depending on the brand, what size do you have on your truck?

Mine are 215/85/R16 BFG's. I measured front tire, on the truck, at 29. 25" tall.

I'm also thinking maybe if I buy some stock 17" take-offs, I might have a better selection of tall tires?

I would really like to have set of 8 lug, 19. 5" forged alloys, with tall tires, but I don't want to spend that much $. (A little over $4K, mntd. , bal. , with shipping. )

Thanks, Ray

 

[JDKammin]

You may want to look into an overdrive unit for your truck. You can drop your rpms for interstate crusing, but still have the pulling power of the 4. 10 gears, when pulling the camper.

 

[LBARTLETT]

I'm also thinking maybe if I buy some stock 17" take-offs, I might have a better selection of tall tires?

I looked into it and my understanding is the 3rd gen 17" dually take-offs won't fit on our 2nd gen duallys. If I'm wrong someone let me know becaause I would have done it and still would!



I'd love to have the 19. 5's but I won't spend the money on a truck that has 200k miles (even though I'll run it another 200k hopefully)



not having taken the time to do the math you might get to where you want with the 235/85R/16, not have any spacing in the rear duals and there are many E rated tires options available



I personally like Michelins and Toyos



Keep us posted on your progress!

 

[SRath]

"Do Taller/Narrower Tires=Better Fuel Mileage?"

You can do a simple and convincing experiment to see just how much difference they might make:

Find a 10-speed bicycle with very narrow, tall, skinny tires.
Then find a similar weight and size bicycle with shorter, fatter tires. Maybe even knobbies.
Inflate all tires to the maximum recommended.

Then put someone very heavy on each bike in turn and try to push them up a hill.

For some real fun, let some of the air out of the tires and repeat the experiment.

Or you can take my word that the skinnier the tire, and the higher the air pressure, the less the rolling resistance is, all other factors such as tread design being the same.

With tread, the more traction a tire gives, the more friction it creates by design. That's what traction is. Trailer tires are always straight-grooved because they don't need to offer traction; just roll easily.

On smooth, dry pavement, maximum traction (friction) comes from wide, soft, under-inflated, smooth tires (racing slicks). Note how the front tires on a dragster are very skinny and higly inflated, though.
True Racing slicks are worthless on wet pavement or no pavement, though. And, therefore, illegal on the street.

If you run in a lot of sand or deep mud, you might want a wide tire that floats across the surface instead of trenching and sinking. If fuel mileage is important, or if you will see frequent snow, narrow tires are better. In snow they offer more PSI to the ground, or to the ice and packed snow. Which is the same reason pickup owners put sandbags in their trucks in the winter. Narrower tires are also better at digging down to a solid surface than wide ones. Plus they roll easier for better mpg on dry roads.

Big, wide tires just look cooler.
(and offer more side-to-side stability for heavy loads and cornering as dually owners are very proud to point out, forgetting how narrow their single front tires are, of course. )

 

[surfbeetle]

Yes, a taller tire will increase mileage and decrease rpm at a given speed, and slow you down when towing. Unless you correct your speedometer for the difference in tire size, your mpg results won't be accurate. Also a skinnier tire gives less rolling resistance and less grip. One last thing, a taller tire will have taller sidewalls and you may experience poorer handling as a result.



I put 17" wheels on my 95 from a 2005 truck. I was amazed how much of an improvement I had from the lower profile tires, the overall tire diameter was the same as with my 16" wheels.

 

[LBARTLETT]

I put 17" wheels on my 95 from a 2005 truck. I was amazed how much of an improvement I had from the lower profile tires, the overall tire diameter was the same as with my 16" wheels

.



I agree with the 17" being a improvement but your truck was single wheels and not a dually??? I don't think the 3rd gen 17" dually wheels will fit our on 2nd gen's will they?? I think it has something to do with the center hole on 4X4's

 

[rjrkihap]

How about tire life? Does narrower tire wear faster vs. a wider tire spreading the load over a greater surface?



Ron

 

[surfbeetle]

LBartlett, to answer your question, single rear wheel, it's a 3/4 ton.



Ron, from what I understand, tire life is really dependent on the tire composition, softer tires wear faster than tires with a harder composition. As for width, you really have to play with air pressure so that your tire is flat on the pavement and not crowned up from too much pressure or the opposite from too little pressure. You can have too much wear on the edge or in the center depending on the pressure.



I know this didn't specifically answer your exact question, but it should assist in getting more life from your tires.

 

[rjrkihap]

Thanks Surfbeetle,



You're absolutely correct about tire pressure. I tend to monitor my tire pressure like a hawk as well as rotate every 5000miles. I just wish I could get more life out of a given set of tires. The best so far are my current Toyo M55's. I'm hoping to hit the 40,000mile mark before having to replace. Every other tire (Michelin stockers, Wild Country, BFG, Wildcat) only lasted 25,000miles. At over $1000 for a set of 4, I want as many miles as possible.



Ron

 

[RHestand]

I'm now checking on a set of six, 8 lug, 19. 5" wheels with tires that are take-offs from a Cummins powered ( 4 cyl. ) Frito/Lay box van. Thats all the info. I have. I e-mailed him for more info. , but no answer yet.

Are any of you guys familiar with what these wheels might fit?

TIA, Ray

 

[jelag]

We found with our trucks that when we went to 19. 5" tires and wheels... 225/70/19. 5. We had a taller tire and it corrected the speedo... .

We searched the tire web sights to find 2 things... true tire diameter when new, overall thread depth and turns per mile...

We chose a Bridgestone RIB tire, but have used Michelin's in the past as well...

A rib tires, rolls easier with less friction than an all season... as well...

Hope this helps...

 

[Flying_gage]

My truck with 4:10/5sp gets about 1 mpg less with 235/85's. I also added a leveling kit at the same time so I am not sure how much that effects it, (prolly a fair amount... . ).