Tire pressure is important!
#21
Re: Tire pressure is important!
While that is true theoretically, in practice it isn't true. The contact patch of the tire x the pressure should equal the car weight. The rigidity of the tire carcass affects deformation of the tread on a car tire and some of the weight may be picked up through the sidewall. However, think about what happens to a bicycle tire on a car (theoretically). If an Escape supports 800 lbs per tire, at 80 psi that requires a contact patch of at least 10 square inches. For a bike tire with a 1.5 inch cross section, that would be almost a 7 inch long contact patch - in other words FLAT. My guess (being too lazy to do the math) is that a bike tire would have to be inflated to about 300 psi just to get the rim somewhat off the ground.
#22
Re: Tire pressure is important!
I was just trying to make a point, not put bicycle wheels on the FEH. by narrower tires, I would expect 185 0r 195 mm. that would require larger dia. rims or an aspect ratio that is not available. And, it would no longer look like an SUV, which may be why it does not alredy have narrow tires!
Interestingly enough (given all the discussion here on cold weather mpg woes) bicycle data also indicates that temperature is as much a factor in rolling resistance as pressure. Tires suck up much more energy in flexure in cold weather than in warm weather.
Diameter is also very important. This why bicycles haven't reduced diameter and why folding bikes are such a compromise. Maybe a little body work and some 30" rims would result in a really high mpg FEH.
#23
Re: Tire pressure is important!
I was just trying to make a point, not put bicycle wheels on the FEH. by narrower tires, I would expect 185 0r 195 mm. that would require larger dia. rims or an aspect ratio that is not available. And, it would no longer look like an SUV, which may be why it does not alredy have narrow tires!
I wonder if you did that would it still be considered OEM?
#25
Re: Tire pressure is important!
Checked mine this morning...front wheels maintained psi after 1 week, but both rear tires were below 32psi.
Is this normal to have the rear tires lose more pressure?
Is this normal to have the rear tires lose more pressure?
#26
Re: Tire pressure is important!
Can somebody here give me real numbers on their claim that higher PSI gave them better MPGs from recommended PSI.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
#27
Re: Tire pressure is important!
If not, you could have more moisture in the rear tires somehow. Which would explain the difference from the front.
#28
Re: Tire pressure is important!
Did you check while your car was cold (like in the morning)? If not, do so in those conditions. Your front tires will always be warmer than your rears because most of the weight is on the front, plus your car is a FWD (or mostly FWD). So that could explain it.
If not, you could have more moisture in the rear tires somehow. Which would explain the difference from the front.
If not, you could have more moisture in the rear tires somehow. Which would explain the difference from the front.
#29
Re: Tire pressure is important!
Can somebody here give me real numbers on their claim that higher PSI gave them better MPGs from recommended PSI.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
#30
Re: Tire pressure is important!
Can somebody here give me real numbers on their claim that higher PSI gave them better MPGs from recommended PSI.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
I have not noticed any difference in MPG (actually a small gain but nothing worth talking about) from recommended PSI to MAX (max on sidewall of tire). The only reason I put more PSIs than recommended is the performance gains in handling and braking. At the cost of a slightly rougher ride.
When I seen I could get 40mpg tanks within my first few fills, I was hooked on the challenge to maintain and improve my mileage. I cranked the tires up to 44psi and it stayed there for a year. I thought exceeding the max sidewall would take any liability away from the tire company and put it on myself back then. I was at the time exceeding 45mpg tanks and satisfied with that results.
During one of the test I was working with Wayne Gerdes on in my FEH, I crank the tires up to 52psi. I didn't lower them back down after the test and thought I'd try and see how much a difference it would make on a tank. You can see by my Miles To Empty on this sig page the results. After hitting a 53mpg tank, I'm convinced that 50psi is an acceptable risk I'm willing to take. Wear has slowed down on my tires and I feel my FWD FEH handles best here in So. FL. We get heavy rain at times and my tires hold the road in cornering and hard stops better I think then they did with 40psi.
BTW, I've had a tire that leaks air from the day I got my FEH. I can tell when one tire is below 44psi just by the drop in mileage and the drag when coasting in neutral. Neutral coasting is most likely the reason I can tell the tires need air right away. When I go EV on the downside of a big bridge, I can tell how my speed increases as I often have to go from "N" to "L" for regen to stay under 40mph.
All the top Hypermilers all agree that tire pressure will effect rolling resistance. Most the top hypermilers I've talked with think I should put more than 50psi in my tires, but that's my limit.
GaryG