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  1. Join Date
    Nov 2009
    Posts
    1,745
    #71
    Quote Originally Posted by miked View Post
    me inflates my tires at 32 psi when cold....they can reach up to 38 or 40 psi when hot.
    For me, I prefer 30PSI cold tire, then when used under my normal routine, it increases to 33-36PSI. For me, its ideal, not bad for my tire, suspension and to my family on board. Note that 6PSI difference from normal creates bad effects based on my research, especially I used normal cars under normal conditions. Of course, racing car is a different story!
    Note: Rim size is 17", normal pressure is 32PSI

  2. Join Date
    Aug 2004
    Posts
    22,710
    #72
    Quote Originally Posted by Noel Salisipan View Post
    Dont be offended, I want to clarify the basis, if it is based on experience or simulation? or experience with simulation?
    I used to avoid overinflating tires, was afraid of the consequences, but after a few decades of driving (I've logged well over 500,000 kilometers in the past ten years on several cars), I've seen the light.

    If you inflate merely to what's written on the sidewall, you often get the edges of the tire wearing out first or feathering. This is because maunfacturer recommended pressures are set for optimum comfort and most modern cars have a fair bit of negative camber on the rear axle for safety. Overinflating slightly makes the tire wear more evenly. Overinflating much more usually (depending on the tire) doesn't make the center of the tire wear faster because modern radial tires don't bulge in the center like older bias-ply tires. What happens when you overinflate is you lessen sidewall deformation, which lessens energy lost to tire flex, which increases economy. On those Petron eco-runs, we would inflate our tires till they were rock hard... and it worked!

    HOWEVER, I don't recommend inflating up to or past the maximum inflation pressure indicated on the sidewall because there's a possibility for suspension or sidewall damage over sharp potholes. HOWEVER (x2), if you underinflate the tires, you run a bigger risk of sidewall damage and folding on sharp pothole edges.

    If you would like more information, you can start here:

    mythbusters tests tyre / tire pressure - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com*
    (actually, ecomodder is a very good resource for learning about fuel economy)

    Basically... inflating up to 40 psi saves gas. Inflating up to 60 psi saves even more gas. But that's way, way beyond the manufacturer's stated safety limit for the tire. 40 psi is well within the safety rating of modern tires, which indicates cold pressure, not hot pressure, so there's always some leeway. Also note that at higher pressures, pressure change due to heat build-up is much, much lower because you have less sidewall flex and tire deformation, which contributes greatly to heat build up. You can tell a tire has a problem with carcass integrity (which affects sidewall rigidity) when it consistently has higher pressure than the others. I used to be like you... stick to 30 psi, whatever the sticker on the door said. But after raising that to about 35 psi, I noticed pressure change after long running was much lower and more consistent than when I used lower pressures.Personally, I don't often go higher than 5 psi over the recommended pressure on the door. I don't do this primarily for economy (that's just a side benefit), I do it for better handling and safety.

    -

    *Note that even though Mythbusters said there would be an increase in wear, they did not test for wear increase. Those who've done the chalk test saw no increase in crown wear at pressures of 40 psi or even 50 psi. BUT: there is a safety risk when you hit a pothole and are inflated to the tire's maximum pressure or beyond. Most who do it have reported no issues at all after years of doing it, but I'd rather err on the side of caution.

    Ang pagbalik ng comeback...

  3. Join Date
    Nov 2009
    Posts
    1,745
    #73
    Well said Niky!
    Its worth to ponder and re-evalute our tire pressure.
    Thanks.

  4. Join Date
    Aug 2004
    Posts
    22,710
    #74
    Yup. But as with anything, YMMV. Your Mileage May Vary.

    Since you're on low-profile tires, you might not need such high inflation rates to ensure good handling and low rolling resistance. Whatever works for you will work for you but might not work for me and vice versa.

    And... it depends on how much you want economy versus comfort. When I'm with my family on long trips, I have to lower my personal ideal pressures a bit to keep them comfy. When I'm alone, I like my rubbers hard.

    Ang pagbalik ng comeback...

  5. Join Date
    Jun 2011
    Posts
    4,509
    #75
    Quote Originally Posted by niky View Post
    I used to avoid overinflating tires, was afraid of the consequences, but after a few decades of driving (I've logged well over 500,000 kilometers in the past ten years on several cars), I've seen the light.

    If you inflate merely to what's written on the sidewall, you often get the edges of the tire wearing out first or feathering. This is because maunfacturer recommended pressures are set for optimum comfort and most modern cars have a fair bit of negative camber on the rear axle for safety. Overinflating slightly makes the tire wear more evenly. Overinflating much more usually (depending on the tire) doesn't make the center of the tire wear faster because modern radial tires don't bulge in the center like older bias-ply tires. What happens when you overinflate is you lessen sidewall deformation, which lessens energy lost to tire flex, which increases economy. On those Petron eco-runs, we would inflate our tires till they were rock hard... and it worked!

    HOWEVER, I don't recommend inflating up to or past the maximum inflation pressure indicated on the sidewall because there's a possibility for suspension or sidewall damage over sharp potholes. HOWEVER (x2), if you underinflate the tires, you run a bigger risk of sidewall damage and folding on sharp pothole edges.

    If you would like more information, you can start here:

    mythbusters tests tyre / tire pressure - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com*
    (actually, ecomodder is a very good resource for learning about fuel economy)

    Basically... inflating up to 40 psi saves gas. Inflating up to 60 psi saves even more gas. But that's way, way beyond the manufacturer's stated safety limit for the tire. 40 psi is well within the safety rating of modern tires, which indicates cold pressure, not hot pressure, so there's always some leeway. Also note that at higher pressures, pressure change due to heat build-up is much, much lower because you have less sidewall flex and tire deformation, which contributes greatly to heat build up. You can tell a tire has a problem with carcass integrity (which affects sidewall rigidity) when it consistently has higher pressure than the others. I used to be like you... stick to 30 psi, whatever the sticker on the door said. But after raising that to about 35 psi, I noticed pressure change after long running was much lower and more consistent than when I used lower pressures.Personally, I don't often go higher than 5 psi over the recommended pressure on the door. I don't do this primarily for economy (that's just a side benefit), I do it for better handling and safety.

    -

    *Note that even though Mythbusters said there would be an increase in wear, they did not test for wear increase. Those who've done the chalk test saw no increase in crown wear at pressures of 40 psi or even 50 psi. BUT: there is a safety risk when you hit a pothole and are inflated to the tire's maximum pressure or beyond. Most who do it have reported no issues at all after years of doing it, but I'd rather err on the side of caution.

    sir i have a van what is the highest pressure that i can use in it? the maximum psi rating on my tires read 44psi... my tire size is 245 70r16...i dont mind about ride comfort coz it got a great suspension...

  6. Join Date
    Aug 2004
    Posts
    22,710
    #76
    Use whatever is comfortable for you. if you want economy, go ahead and try 40 psi... lower it a bit if it's too bouncy.

    Ang pagbalik ng comeback...

  7. Join Date
    Jun 2011
    Posts
    4,509
    #77
    Quote Originally Posted by niky View Post
    Use whatever is comfortable for you. if you want economy, go ahead and try 40 psi... lower it a bit if it's too bouncy.
    sir.. can i go over 44psi? is it ok if i put in 49psi? its a 2ton van... i want to put in the max inflation possible...

  8. Join Date
    Aug 2004
    Posts
    22,710
    #78
    If the van is for cargo carrying, I'd say stay within the maximum number.

    This is because an ultra-stiff tire does not cushion the suspension from shock as well as a tire inflated within the suggested pressure zone. If you hit a pothole with a full load, this increase the chances of the rubber 'bruising', leaving an uneven lump in the tread. You can experiment if you want, but this experimentation is at your own risk and at the risk of the safety of your driver. note that unlike more modern car tires, some truck tires are notorious for blowing up...

    Ang pagbalik ng comeback...

  9. Join Date
    May 2011
    Posts
    481
    #79
    when speaking of safety, overinflating tires is just as unsafe as underinflating. in terms of tire contact with the road, overinflated tires have less footprint and under inflated tires lose contact towards the middle of the tire patch in contact with the road. remember, your car is only in contact with mother earth at four places about the size of cup saucers

  10. Join Date
    Nov 2005
    Posts
    34,240
    #80
    para lang makatipid konte mag o-over inflate kayo?

    there are other ways to save fuel

    don't know about you guys but i'd rather have more rubber on the road for traction than less rubber on the road just to save a few pesos

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Increased fuel economy from over-inflated tires