Tires and fuel economy. Do they really make a difference?
Moderator: volvite
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jungleexplorer
- Posts: 9
- Joined: Wed Sep 02, 2009 7:52 pm
Tires and fuel economy. Do they really make a difference?
I will make this short and sweet. I have a 1992 Pathfinder that I have owned for almost 10 years. I has been the best car I have ever owned with the exception of fuel economy. It had off road tires (BFgoodwrench 31X10.5 R15 ALL Terrain) when I bought it and still does today (second set). It gets 15 MPG Highway and 13 MPG City. It needs new tires and I don't do any off roading anymore so I am thinking about going back with the original size tires ( P235/75 R15) if it will improve my MPG. Do you think it will improve my MPG if I go back with the original size tires? If so, how much do you think it will improve? Thank for the advice.
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jungleexplorer
- Posts: 9
- Joined: Wed Sep 02, 2009 7:52 pm
Thanks
3 to 5 MPG better. Humm... That would be great but I would be overjoyed if just got 2 GPM better. fueleconomy.gov says that the original EPA estimate for the 1992 Pathfinder (4X4 V6 Standard) was 17 highway and 15 city. I would be happy if I could get that. Thanks again.
Re: Thanks
I'd be heated if I was getting 2 Gallons Per Mile.jungleexplorer wrote:3 to 5 MPG better. Humm... That would be great but I would be overjoyed if just got 2 GPM better. fueleconomy.gov says that the original EPA estimate for the 1992 Pathfinder (4X4 V6 Standard) was 17 highway and 15 city. I would be happy if I could get that. Thanks again.
I would think that going back to the original tire size will increase mpg as well. By how much? Don't know.
By going back to smaller tires...
When a tire is narrower, surface area that pushes through to move forward decreases. That also brings the body to slightly closer/lower to the ground. Those requires the engine to work less.
When tires are smaller, each tires weigh less. The engine has to work less to rotate the tires to move forward.
If you could remember, come back and report to us if you see any changes.
By going back to smaller tires...
When a tire is narrower, surface area that pushes through to move forward decreases. That also brings the body to slightly closer/lower to the ground. Those requires the engine to work less.
When tires are smaller, each tires weigh less. The engine has to work less to rotate the tires to move forward.
If you could remember, come back and report to us if you see any changes.
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jungleexplorer
- Posts: 9
- Joined: Wed Sep 02, 2009 7:52 pm
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jungleexplorer
- Posts: 9
- Joined: Wed Sep 02, 2009 7:52 pm
Initial Results. 4MPG!
Well, the initial results of my first road trip were better then I could have hoped for. I filled up at point A and drove 154 miles and filled up again. It took almost 8 gallons to fill up. So that equals out to be better then 19 MPG with the new tires (P235/75 R15), up from 15 MPG with the old tires (31X10.5 R15). I was hoping for 2MPG better, so I was thrilled to see 4 MPG.
It will take several more test to tell exactly what the average increase will be, but the initial result were better then I expected. Just in case you were wondering what kind of tire I ended up getting; Peerless Tire had a sale on their Guide Trail tires for $59 each, so I went with them. I have never heard of this brand before, but they look really nice with the white letters out. They also have a medium all terrain tread style that I think looks better on a Pathfinder then a regular street tire. The road noise has diminished by about 75 percent over the old tires and acceleration has increased noticeable. They ride a lot smoother too. I am very pleased with them for what I need them for, which is mostly highway and dirt roads. They are only 4 ply so I don't think they could handle any serious off roading, even though they kind of look like the could.
It will take several more test to tell exactly what the average increase will be, but the initial result were better then I expected. Just in case you were wondering what kind of tire I ended up getting; Peerless Tire had a sale on their Guide Trail tires for $59 each, so I went with them. I have never heard of this brand before, but they look really nice with the white letters out. They also have a medium all terrain tread style that I think looks better on a Pathfinder then a regular street tire. The road noise has diminished by about 75 percent over the old tires and acceleration has increased noticeable. They ride a lot smoother too. I am very pleased with them for what I need them for, which is mostly highway and dirt roads. They are only 4 ply so I don't think they could handle any serious off roading, even though they kind of look like the could.
Re: Initial Results. 4MPG!
I'm guessing the 235s are stock on your Pathfinder? 2 other things to take into account: the gearing would have been optimal for the stock size tire, and the mpg readings would also have been based on stock tire size.jungleexplorer wrote:Well, the initial results of my first road trip were better then I could have hoped for. I filled up at point A and drove 154 miles and filled up again. It took almost 8 gallons to fill up. So that equals out to be better then 19 MPG with the new tires (P235/75 R15), up from 15 MPG with the old tires (31X10.5 R15). I was hoping for 2MPG better, so I was thrilled to see 4 MPG.
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