random thought on big tires

[88Racing]

It shouldn't be the extra weight of the tires being larger.
Mass is the better term for the added size.
Mass deals with more than the term weight does.
http://physics.about.com/od/glossary/g/mass.htm

[ticopowell]

Depends on the motor, the gas V8 is the same for the 150, 250, and 350, but the 150 doesn't get the v10 or the diesel, so it doesnt always have the same motor.
and yeah ration's are kinda interesting here, i much prefer a good ratio

[Longshot270]

Originally Posted by 88Racing

I thought the same motor was used?

It shouldn't be the extra weight of the tires being larger.
Mass is the better term for the added size.
Mass deals with more than the term weight does.
Mass - definition of mass

I was comparing a ranger sized truck to a F250. The largest motor for a ranger is the 4.2 V6, a motor that isn't even an option for the F250. There is probably a ton difference between the two vehicles.

Mass and weight can get complicated, just keep in mind that weight is conditional and mass is not.

I know Jack recently talked about tire size on another thread where he compared the mechanical disadvantage of the larger tires but I dont remember what it was called. I'm sure he's got the formula somewhere.

[cleatus12r]

Just for the sake of discussion......

I ran 49" tall tires on my old 95 F350 PSD. The truck had 4.10:1 gearing in the differential. I could NOT drive the truck 75 MPH in overdrive (5th gear) because the engine simply could not keep momentum. I went from 15 MPG highway with the stock tires (265/75-16) to roughly 5 MPG highway with the 49" tires even though gearing remained the same.

Mathematically speaking, I went from a tire that made 637 rev/mile to a tire that made 413 rev/mile. This is a nearly 35% difference. As far as MPG goes, the difference is nearly the same (33%). The truck would barely get out of it's own way, turned 1200 RPM at 75 MPH in 5th gear, but the mileage decreased significantly.

[majek5]

Originally Posted by cleatus12r

Just for the sake of discussion......

I ran 49" tall tires on my old 95 F350 PSD. The truck had 4.10:1 gearing in the differential. I could NOT drive the truck 75 MPH in overdrive (5th gear) because the engine simply could not keep momentum. I went from 15 MPG highway with the stock tires (265/75-16) to roughly 5 MPG highway with the 49" tires even though gearing remained the same.

Mathematically speaking, I went from a tire that made 637 rev/mile to a tire that made 413 rev/mile. This is a nearly 35% difference. As far as MPG goes, the difference is nearly the same (33%). The truck would barely get out of it's own way, turned 1200 RPM at 75 MPH in 5th gear, but the mileage decreased significantly.

But it looked good gettin the 5 mpg.

[cleatus12r]

Yeah it did. You wouldn't believe the amount of attention that thing gave me......I even got "flashed" twice with the wife in there with me.

Those were the days.

[AZFXFOUR]

When i went to 35s on my f150 I DID notice slightly better mileage on the highway because the engine was not working as hard to MAINTAIN the speed. But I also suffered worse mileage around town or stop and go because the engine had to over come the mass and increased rolling resistance of the larger tires. So you pretty much break even. Now if you ran a taller very skinny tire you might get a little better result.

[matt7.350]

Ok so what im getting from this is 49" tires =