tire size and gas mileage ....... opinions
Winching
Joined: Jul 2007
Posts: 504
Likes: 58
From: Richmond, VA
RE: tire size and gas mileage ....... opinions
ORIGINAL: Darover
But alot of people forget to multiply the recorded mileage by the percentage of the tire difference. 245/75-16 are about 5% bigger than the original 29 inch tires. Therefore, you need to multiply the recorded mileage by 5%. So if you've gone 300 miles on a tank, you really went 315.
But alot of people forget to multiply the recorded mileage by the percentage of the tire difference. 245/75-16 are about 5% bigger than the original 29 inch tires. Therefore, you need to multiply the recorded mileage by 5%. So if you've gone 300 miles on a tank, you really went 315.
I'll use that factor when I calculate this tank. Recalculating my last tankful gives me a new mileage of 14.2 MPG - still worse than any otherfillup (by 2 MPG), butnot quite as bad as initially calculated.
Dave
Winching
Joined: Jul 2007
Posts: 504
Likes: 58
From: Richmond, VA
RE: tire size and gas mileage ....... opinions
ORIGINAL: andrewmcoffin
Dave, how are you measuring your mpg? How do you come up with a figure as precise as 13.5?
May sound like a dumb question, but I honestly want to know--I'm trying to figure out what sort of mpg I'm really getting...
-Andrew
Dave, how are you measuring your mpg? How do you come up with a figure as precise as 13.5?
May sound like a dumb question, but I honestly want to know--I'm trying to figure out what sort of mpg I'm really getting...
-Andrew
Cheers,
Dave
Recovery Vehicle
Joined: Sep 2007
Posts: 940
Likes: 4
From: Ballston Lake, NY
RE: tire size and gas mileage ....... opinions
ORIGINAL: jkid
My opinion is that the taller tire gives you better mileage. It would be like adding taller gears. If you think that withextremelysmall tires,at the same rpm you won't be going anywhere.So with a taller tire you would get more bang for your buck so to speak. Go too big and your engine will not be able to handle the load though. A wider tire would just add more weight and resistance too. So, tall and skinny tires; just like a rover should have. I had the BFG AT's on my Jeep and went up in size with the same tire. I think my mileage got better, but I can't confirm it. Remember, most people with bigger wires also have a much more aggressive tread, which affects the mix too.
My opinion is that the taller tire gives you better mileage. It would be like adding taller gears. If you think that withextremelysmall tires,at the same rpm you won't be going anywhere.So with a taller tire you would get more bang for your buck so to speak. Go too big and your engine will not be able to handle the load though. A wider tire would just add more weight and resistance too. So, tall and skinny tires; just like a rover should have. I had the BFG AT's on my Jeep and went up in size with the same tire. I think my mileage got better, but I can't confirm it. Remember, most people with bigger wires also have a much more aggressive tread, which affects the mix too.
Recovery Vehicle
Joined: Feb 2007
Posts: 1,074
Likes: 2
From: CDA, ID
RE: tire size and gas mileage ....... opinions
I went another direction, instead of running the 235/70/16 that came on the ruck I went to a 225/75/16 GoodYear MTR. The overall circumfrence is so minimal yet the extra tread on the sidewalls make up for the loss in section width. I also gained a more agressive tire without the sacrifices of the mileage issue.
Winching
Joined: Jul 2007
Posts: 504
Likes: 58
From: Richmond, VA
RE: tire size and gas mileage ....... opinions
ORIGINAL: handsome rob
I went another direction, instead of running the 235/70/16 that came on the ruck I went to a 225/75/16 GoodYear MTR. The overall circumfrence is so minimal yet the extra tread on the sidewalls make up for the loss in section width. I also gained a more agressive tire without the sacrifices of the mileage issue.
I went another direction, instead of running the 235/70/16 that came on the ruck I went to a 225/75/16 GoodYear MTR. The overall circumfrence is so minimal yet the extra tread on the sidewalls make up for the loss in section width. I also gained a more agressive tire without the sacrifices of the mileage issue.
Dave
Recovery Vehicle
Joined: Feb 2007
Posts: 1,074
Likes: 2
From: CDA, ID
RE: tire size and gas mileage ....... opinions
Yes, sorry I did not state that in my original post. I was showing that you can go woth a more aggressive tire and get sidewall height and also reduce the drag of the mid section. SO far I am heppy with it but have not done any great wheeling since I put them on. I need to fix this engine issue first.
Recovery Vehicle
Joined: Mar 2008
Posts: 755
Likes: 2
From: Sevierville TN
Im running 225/75/16s but have only had them on for a couple of weeks. They look great on the truck and are, I think, one inch taller in diameter to the stock tires I had on it when I bought it.
EDIT: I use Gas Cubby on my IPhone to track my gas milage and it is a really neat program. I haven't had it long enough to get real accurate results but the more you do the better it is at approximating MPG. I also use it to keep up with how much I have spent on services and parts. It gives you graphs and regular data.
EDIT: I use Gas Cubby on my IPhone to track my gas milage and it is a really neat program. I haven't had it long enough to get real accurate results but the more you do the better it is at approximating MPG. I also use it to keep up with how much I have spent on services and parts. It gives you graphs and regular data.
Last edited by salve7; May 15, 2009 at 05:13 PM.
Mudding
Joined: Mar 2009
Posts: 210
Likes: 0
A very good point. 255/65/16 tires have a circumference of 91.266" and 245/75/16 tires have a circumference of 95.721", for a difference of 4.455" or roughly 5%, as you suggest.
I'll use that factor when I calculate this tank. Recalculating my last tankful gives me a new mileage of 14.2 MPG - still worse than any otherfillup (by 2 MPG), butnot quite as bad as initially calculated.
Dave
I'll use that factor when I calculate this tank. Recalculating my last tankful gives me a new mileage of 14.2 MPG - still worse than any otherfillup (by 2 MPG), butnot quite as bad as initially calculated.
Dave
I used my gps and on mine with 245/75/16 BFG AT's its 5.3% more mileage that it shows.
The tire weight makes a big difference a stock tire can be 10 to 15 lbs lighter than a off road tire.
One would think that a taller tire would off set the loss of mileage by lowering the RMP the motor run's at for the same speed but it doesn't.
In a VW TDI Forum I'm on larger tires = less MPG always even if used with a lighter wheel and tire, its roll resistance.
With the people on there if they are not getting 50 mpg or better its broken.
I just like not having to stop for fuel for 700 miles out on the road.
