tire pressure
#1
tire pressure
I hear lots of complaints on fuel economy, but how many and how often do you folks check your tire pressure?
To throw some gas onto the fire... what pressure are you running?
I'm running my 31-10.5-15's at 42psi on the hwy and drop down to 30 offroad. As part of my hypermiling I'm averaging 24mpg in a mix of city/hwy driving. I take a fair hit offroad but that's the price I pay playing.
All this is done in a Mazda B-4000 SE X-cab 4x4 w/ 182.xxxmi. on it.
To throw some gas onto the fire... what pressure are you running?
I'm running my 31-10.5-15's at 42psi on the hwy and drop down to 30 offroad. As part of my hypermiling I'm averaging 24mpg in a mix of city/hwy driving. I take a fair hit offroad but that's the price I pay playing.
All this is done in a Mazda B-4000 SE X-cab 4x4 w/ 182.xxxmi. on it.
#8
#11
I've a good book at work. It's "fundimentals of vehicle dynamics" and the class is taught at UofM.
In it the writer says that once a properly sized (stock tire) is at 31-32psi the rolling resistance with increased pressures only goes down a very very small amount. Unfortunately there is a whole lot of math and circumstances that go into figuring out how much PSI to run in a particular tire/car situation.
Just know this. If an aftermarket tire on a ranger is rated at a load higher than the stock tire was? The running psi needs to be lower.
As a basis take my stock 265 goodyears when at 33 psi and the truck loaded down towing a boat. The tire sidewall tempature is in the 20F more than ambient range. (pull over into a rest stop and measured with a infared gun)
Use that as a "standard". If your say.. 32x11.5 tires are running hotter than that? You need to increase the psi a little. If they are lower than that? Your most likely prematurely wearing out the center of the tread.
Increasing psi more than 33-34 and you really are not gaining a "cost save" because wearing the tires out sooner is way more expensive than the little extra gas you burned.
Rich
In it the writer says that once a properly sized (stock tire) is at 31-32psi the rolling resistance with increased pressures only goes down a very very small amount. Unfortunately there is a whole lot of math and circumstances that go into figuring out how much PSI to run in a particular tire/car situation.
Just know this. If an aftermarket tire on a ranger is rated at a load higher than the stock tire was? The running psi needs to be lower.
As a basis take my stock 265 goodyears when at 33 psi and the truck loaded down towing a boat. The tire sidewall tempature is in the 20F more than ambient range. (pull over into a rest stop and measured with a infared gun)
Use that as a "standard". If your say.. 32x11.5 tires are running hotter than that? You need to increase the psi a little. If they are lower than that? Your most likely prematurely wearing out the center of the tread.
Increasing psi more than 33-34 and you really are not gaining a "cost save" because wearing the tires out sooner is way more expensive than the little extra gas you burned.
Rich
#13
#14
Rich
#16
I run 22 PSI all the way around on the road and 8-10 off the road. anyone running over 35 on a ranger IMO is just wearing out tires and possibly causing unsafe driving because the contact patch is less.
#22
http://www.officer.com/article/artic...on=19&id=27281
Here is the source and reason for running my tires "overinflated"
The sidewall says 50psi max.
The wear on the center isn't something I've seen but the wear on the outer tread has been dramatically reduced and my mpg has gone up. Seems like a win/win situation to me.
Here is the source and reason for running my tires "overinflated"
The sidewall says 50psi max.
The wear on the center isn't something I've seen but the wear on the outer tread has been dramatically reduced and my mpg has gone up. Seems like a win/win situation to me.
#23
Never ever ever over inflate your tire to more then 5 PSI over the manufacturers recommendation. Also never ever over inflate them past the numbers on the tire. If you over inflate you can loose the handling characteristics of your vehicle. Also your tires are a vital part of your suspension system. Your tires are what cushion you from all the little bumps on the road, not your shocks/springs.
Also if anyone ever tells you that nitrogen makes it ride better or gets you better gas milage, you can be rest assured that they are lying. The only thing nitrogen does is help slow down the leaking that happens naturally with tires. Also since nitrogen expands at a slower rate it will help prevent your tire pressure from fluctuating.
This is comming from a Michelin Certified tire installer.
Oh also on the '04 rangers the placard and the owners manual says the recommended PSI is 30. This was changed later in the year to be 35 PSI. I know this is true for the 04s I dont know about other years.
Also if anyone ever tells you that nitrogen makes it ride better or gets you better gas milage, you can be rest assured that they are lying. The only thing nitrogen does is help slow down the leaking that happens naturally with tires. Also since nitrogen expands at a slower rate it will help prevent your tire pressure from fluctuating.
This is comming from a Michelin Certified tire installer.
Oh also on the '04 rangers the placard and the owners manual says the recommended PSI is 30. This was changed later in the year to be 35 PSI. I know this is true for the 04s I dont know about other years.
Last edited by malydeen; 07-15-2008 at 04:32 PM.
#25
question. my girlfriends tires on her jeep say that they have a max of 80psi. Now i know that that is WAY to high, but what is a good psi to set them? Its a 4banger with 33's.. Shes gettng ****TY gas mileage... i put them up to around 45 today.. they were all below 28..lol.
IMO I'd try them in the 30psi area.
You might try slowly crossing some sand or dirt to see the pattern it leaves at different pressures.
Rich
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