WRX odometer readings switching between 205/55/16 -> 225/50/16? Need explaination.
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Uhh... no. Adding air to affect OD of your tires guarantees uneven wear and accelerated replacement intervals. If you change tire sizes all you need to do is be aware of the effect on your odometer and speedometer.
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Originally Posted by BAN SUVS
Uhh... no. Adding air to affect OD of your tires guarantees uneven wear and accelerated replacement intervals. If you change tire sizes all you need to do is be aware of the effect on your odometer and speedometer.
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running a slightly higher pressure can have a big difference on fuel economy compared to an under inflated tire.
most common way people probably understand it is bicycle tires. pump them up to a high pressure and you can ride pretty easy on them, drop the pressure and you get tired a lot quicker than before. since the tires are absorbing more of the energy you have to exert more to keep the same speed
most common way people probably understand it is bicycle tires. pump them up to a high pressure and you can ride pretty easy on them, drop the pressure and you get tired a lot quicker than before. since the tires are absorbing more of the energy you have to exert more to keep the same speed
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Originally Posted by ish
running a slightly higher pressure can have a big difference on fuel economy compared to an under inflated tire.
most common way people probably understand it is bicycle tires. pump them up to a high pressure and you can ride pretty easy on them, drop the pressure and you get tired a lot quicker than before. since the tires are absorbing more of the energy you have to exert more to keep the same speed
most common way people probably understand it is bicycle tires. pump them up to a high pressure and you can ride pretty easy on them, drop the pressure and you get tired a lot quicker than before. since the tires are absorbing more of the energy you have to exert more to keep the same speed
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Inflating tires slightly to increase fuel economy is different than inflating them to deal with the smaller diameter tire, which is the primary focus of this thread. I also run higher than recommended pressures, usually 38-40 psi, but for other reasons.
Holy crap all this stuff made my head spin.
I have an idea...why don't you go on a roadtrip with a trail car (stock one with working odo). Go pretty far and have the trail car pace you all the way.
When you get to your destination compare odometer numbers.
Oh and yeah I did the wider tires too...haven't noticed any big difference in mileage but I do mostly city driving so you know how that is.
I have an idea...why don't you go on a roadtrip with a trail car (stock one with working odo). Go pretty far and have the trail car pace you all the way.
When you get to your destination compare odometer numbers.
Oh and yeah I did the wider tires too...haven't noticed any big difference in mileage but I do mostly city driving so you know how that is.
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Originally Posted by rustokman
Friction does not depend on surface area. The formula for friction is Force of friction(static or kinetic) = Normal force (the force that is pushing againts the wheels opposite the gravity force, newton's law) * Mu (frictoin coefficient).
F = (mu) *(Fn)
Wider tires provide more of a distribution of toque placed on the tire by the road surface. Surface area of contact patch has nothing to do with the friction. It is his odometer that is off and the new tires are bigger and so they weigh more and the car expends more fuel to spin them.
Don't mean to be snotty here, I am majoring in Mechanical engineering and minoring in physics and math.
F = (mu) *(Fn)
Wider tires provide more of a distribution of toque placed on the tire by the road surface. Surface area of contact patch has nothing to do with the friction. It is his odometer that is off and the new tires are bigger and so they weigh more and the car expends more fuel to spin them.
Don't mean to be snotty here, I am majoring in Mechanical engineering and minoring in physics and math.
BTW, I will be majoring in ME at Cornell next year
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What pressure are you running on these tires? It could just be because they are wider?
Last edited by Impretzle; May 3, 2005 at 01:16 AM.
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