What PSI On 03 M45??
What PSI On 03 M45??
What PSI are you all using for your your stock OEM 03 M45 wheels? Is 40 optimal in normal, 75 deg, weather?
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auditech10
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szh
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Unfortunately, no longer a Nissan or Infiniti, but continuing here at NICO! - Location: San Jose, CA
Re: What PSI On 03 M45?? (eskay)
I'd say going below 32 to 33 psi is asking for trouble if the tire load index is not up to snuff.
Particularly given that tire pressure reliably drops 1 to 2 psi in a couple of weeks. And, if your gauge is not accurate!
So, I'd strongly recommend doing 36 psi (all round) and adjusting from there to get the ride comfort/wear/handling you want - higher than 36 is okay, lower than 36 should be done only if really desired and it gives you a softer ride!
As always, remember to measure when the tires are cold. First thing in the morning, in a closed garage, etc., etc., etc.
Z
Particularly given that tire pressure reliably drops 1 to 2 psi in a couple of weeks. And, if your gauge is not accurate!
So, I'd strongly recommend doing 36 psi (all round) and adjusting from there to get the ride comfort/wear/handling you want - higher than 36 is okay, lower than 36 should be done only if really desired and it gives you a softer ride!
As always, remember to measure when the tires are cold. First thing in the morning, in a closed garage, etc., etc., etc.
Z
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: What PSI On 03 M45?? (szhosain)
44psi max tires are tested in lab at 35psi to graph parameters. This is 80% of max pressure..............using the same % of 51psi tires is 40.5 psi.
Most manufactures select tire load index that corresponds to 100% of dynamic load [static plus weight shift] on a front tire under maximal braking 1G load................if you brake alot frequently a better [higher load index] tire is often a good investment, as used vs. reserve ratio improvements translate into longer tread life.
Depending on agressiveness this leaves enough reserve to tolerate emergency braking for 3-5 seconds and agressive driving for longer [minutes]............luckily tires self adjust upward as they heat up from stress.
Most manufactures select tire load index that corresponds to 100% of dynamic load [static plus weight shift] on a front tire under maximal braking 1G load................if you brake alot frequently a better [higher load index] tire is often a good investment, as used vs. reserve ratio improvements translate into longer tread life.
Depending on agressiveness this leaves enough reserve to tolerate emergency braking for 3-5 seconds and agressive driving for longer [minutes]............luckily tires self adjust upward as they heat up from stress.
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szh
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Unfortunately, no longer a Nissan or Infiniti, but continuing here at NICO! - Location: San Jose, CA
Re: What PSI On 03 M45?? (Q45tech)
Dennis (Q45tech),
According to the last time I read the Tire And Rubber Association handbook info (was a few years ago), the standards for 51 psi max tires had not yet been set. So, these "higher-max-pressure" tires were still being tested at 35 psi in the lab for load conditions and failures, etc. at that time.
I have not kept up with the latest info though, so ... do you know if this has changed recently at all? Have they settled on a 40psi test value or any value near there?
If so, then it would indeed be very important for us to use higher psi, but, given the car mftr recommendations today (Infiniti still says 33psi for the M today), I'd guess that the lab test standard is still 35 psi.
And, if it is still at 35psi test, my guess is that this standard will not change ... mostly because the average population is too used to setting low tire pressures and will not get used to "set your car to 40psi" and are likely to get themselves in trouble with tire failures!
Z
According to the last time I read the Tire And Rubber Association handbook info (was a few years ago), the standards for 51 psi max tires had not yet been set. So, these "higher-max-pressure" tires were still being tested at 35 psi in the lab for load conditions and failures, etc. at that time.
I have not kept up with the latest info though, so ... do you know if this has changed recently at all? Have they settled on a 40psi test value or any value near there?
If so, then it would indeed be very important for us to use higher psi, but, given the car mftr recommendations today (Infiniti still says 33psi for the M today), I'd guess that the lab test standard is still 35 psi.
And, if it is still at 35psi test, my guess is that this standard will not change ... mostly because the average population is too used to setting low tire pressures and will not get used to "set your car to 40psi" and are likely to get themselves in trouble with tire failures!
Z
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: What PSI On 03 M45?? (szhosain)
Not offical just from discussions a Tire Society meetings.Side wall stiffness is much more linear with 51 psi tires as there is NOTHING [93%] other than air to support.
http://www.tiresociety.org/pdf...b.pdfh ... ai...e.htm
FYI:Table III-7Braking Distance (in feet) provided by GoodyearWet Stopping Distance (0.050” water depth) Surface Speed ............................17 psi 25 psi 29 psi 35 psi 40 psiMacadam 25 mph 32.4 30.8 29 27.4 25.9Macadam 45 mph 107.6 101 100.8 98.6 97.1Concrete 25 mph 47.4 48.2 48.2 48.0 47.7Concrete 45 mph 182.6 167.2 167.4 163.6 158.2
Obviously as you increase psi the contact patch area decreases and the presssure exterted increases to the road so higher psi improves wet braking distances and increase the speed at which hydroplanning begins.
That alone should be enough to mandate the higher psi.
In 2000 the average tire placard for cars listed 30 psi as the recommended pressure????????????????????? Causing a 10 foot extra stopping distance in rain from just 45 mph!
These things are secrets kept from the public, unless you are a tire guy and know where to look.
The funeral home and critical care homes depend on 40,000 deaths per year from auto impacts and the 1 million severe injuries.
If everyone drove on less than half worn PS2 [or equivalent] in Summer and REAL Ice tires in winter..............so many health care people would be looking for work.
http://www.tiresociety.org/pdf...b.pdfh ... ai...e.htm
FYI:Table III-7Braking Distance (in feet) provided by GoodyearWet Stopping Distance (0.050” water depth) Surface Speed ............................17 psi 25 psi 29 psi 35 psi 40 psiMacadam 25 mph 32.4 30.8 29 27.4 25.9Macadam 45 mph 107.6 101 100.8 98.6 97.1Concrete 25 mph 47.4 48.2 48.2 48.0 47.7Concrete 45 mph 182.6 167.2 167.4 163.6 158.2
Obviously as you increase psi the contact patch area decreases and the presssure exterted increases to the road so higher psi improves wet braking distances and increase the speed at which hydroplanning begins.
That alone should be enough to mandate the higher psi.
In 2000 the average tire placard for cars listed 30 psi as the recommended pressure????????????????????? Causing a 10 foot extra stopping distance in rain from just 45 mph!
These things are secrets kept from the public, unless you are a tire guy and know where to look.
The funeral home and critical care homes depend on 40,000 deaths per year from auto impacts and the 1 million severe injuries.
If everyone drove on less than half worn PS2 [or equivalent] in Summer and REAL Ice tires in winter..............so many health care people would be looking for work.