My Tire Hyper-Inflation Story... What's Yours?

[AstroTurf]

Astro14,

I absolutely L O V E D the Nokians. I think that they are truly one of the best tire manufacturers in the world. A Forward Thinking Company.
The Nokians would have lasted longer, But I'm a Scaredy Cat when it comes to sharing the road with rain/water. 64,500 miles when they were replaced. 5 tire rotation. Vehicle placard suggested pressure 38 psi, I tested and finally settled on 41 psi.
Great Choice for your Wife's car. You will never look back or worry about her safety with those tires.

As far as my current tire pressure choice. I have been forced into this situation, so to speak. I would much rather, (hindsight I know), Have run with the parameters of my last set of tires. Start at placard, and inflated about 3 to 4 more psi.
It is a long story that I am trying to sort out on this forum. Hint... 35, 44, and 51 psi. Plus I will add that the tire manufacturers have recently reduced P-Rated tires to 90 percent of their capacity for anything larger than a car.

I like the fact that Off Shore producers and performance rated vehicles have a dual pressure placard. I am the victim of a lazy MFG. But, I will move slowly and carefully for the best results.

Have a good one, Jim

 

[Astro14]

I loved the Nokian Hakkapeliitta snow tires when I lived in Vermont - incredible grip, particularly in that slush/ice mix that happens near freezing...went through 2 sets on an older Volvo (RWD). That's why I chose the WR G2s... It rarely, if ever, snows here, but if it does, she is prepared.

I agree completely that a single pressure can't cover the range of operating conditions encountered by different drivers. My 1996 Explorer (that I got in 2000), as an example, said 26/26 - I knew from the beginning that was way too low. I settled on 32/32, which gave me decent wear, better response and a reasonable ride...it was that year that the whole Explorer tire issue made the national news...and part of the problem was that ridiculously low placard pressure (along with poor maintenance by owners, high heat, overcontrolling a blowout, etc...)

My 1981 MB 240D had the tire pressure placard under the fuel door...I don't remember exactly, but it was along the lines of 28/28 unloaded and 32/32 for loaded...and the owner's manual talked about adding 4 PSI (cold) for high-speed...which would make it 36/36....

Though, if you've ever driven the venerable 240D...you would know that "high speed" is an oxymoron in that car...

 

[rpn453]

2004 Mazda3. 205/50R17 summer, 205/55R16 winter. 32/32 recommended on tire placard.

I don't normally go much over the placard for street driving because the ride is punishing, straight-line traction decreases, and cornering traction becomes poor on rough pavement. But I did a track day last weekend with the Mazda3 and I started at 40/37 in an attempt to preserve the edge of the tread and to allow me to start high so that I wouldn't need to carry a compressor. The tires were very slippery at that pressure. Dropped 2 psi and traction improved greatly. Dropped another 1 psi later with further improvement. Dropped yet another 1 psi with further improvement. I will be starting with 35/32 for my next track day.

For traction on straight-line acceleration, 28 psi is the best (and lowest) of the pressures I've tried, but there is too much tire roll in corners below 32 psi front.

I would only increase tire pressure substantially for street use if I noticed underinflation wear. I actually noticed a bit of overinflation wear on my Michelin Pilot Sport A/S at 35/32, so I am now using 33/30. OEM Goodyear RS-As showed mild underinflation wear at 32/32.

I also once hyper-inflated my winter tires to 44/44 due to a defective tire pressure gauge that was reading 12 psi low. Traction was poor.

 

[AstroTurf]

Originally Posted By: rpn453
2004 Mazda3. 205/50R17 summer, 205/55R16 winter. 32/32 recommended on tire placard.

I don't normally go much over the placard for street driving because the ride is punishing, straight-line traction decreases, and cornering traction becomes poor on rough pavement. But I did a track day last weekend with the Mazda3 and I started at 40/37 in an attempt to preserve the edge of the tread and to allow me to start high so that I wouldn't need to carry a compressor. The tires were very slippery at that pressure. Dropped 2 psi and traction improved greatly. Dropped another 1 psi later with further improvement. Dropped yet another 1 psi with further improvement. I will be starting with 35/32 for my next track day.

For traction on straight-line acceleration, 28 psi is the best (and lowest) of the pressures I've tried, but there is too much tire roll in corners below 32 psi front.

I would only increase tire pressure substantially for street use if I noticed underinflation wear. I actually noticed a bit of overinflation wear on my Michelin Pilot Sport A/S at 35/32, so I am now using 33/30. OEM Goodyear RS-As showed mild underinflation wear at 32/32.

I also once hyper-inflated my winter tires to 44/44 due to a defective tire pressure gauge that was reading 12 psi low. Traction was poor.


Good Story.

My Wife's Prelude had 205/55 16 as the stock tire size. It had two placard pressures, 29 for regular conditions, and 41 for sport driving. It rode stiff at 41 which is were I ran them. Nitto NeoGen Tires, But they weren't tires... they were road magnets.

Did you buy the summer set size as a performance upgrade? Rim specs?

Thanks for the story.

Jim

 

[Volvo_ST1]

205/55/16 Yokohama S.drive

51 psi max

The car manual and sticker show suggested tire pressure ranging from 32 psi to 42 psi in the front and rear, depending on number of passengers and baggage in the trunk. That's the suggested pressure for the 205/55/16. For other tire sizes the figures are different (up to 46 psi in the rear).

I run 42 psi year-round. I am not Colt Seavers and stick with my strategic driving.

 

[AstroTurf]

Volvo_ST1,

I am glad you found your standard... 42 psi.

I see so many people topping off their tires at the gas station, without following up with a gauge.

Thanks for sharing, Jim

PS Was Colt a Stunt Driver? I've heard that they can run as much as 100 psi in their tires for some of their stunts.

Again Thanks.

 

[Astro14]

You're too young...

Colt Seavers - "The Fall Guy"...played by Lee Majors....

"'Cuz I'm the unknown stuntman that made Eastwood such a star..."

http://en.wikipedia.org/wiki/The_Fall_Guy

 

[AstroTurf]

Actually, I'm an Old Guy...

Who forgot all about that show.

Thanks for bringing that back up, (like last nights dinner).

Just Joking, Jim

PS Astro14, I am finding through my research that many people do not perform regular psi checks... Scary.

Have a Good One, Colt out.

 

[AstroTurf]

Here are a couple of Real Pros...

Look at the advice they give Alice, IE see how the other half lives.

LOLz, Jim

http://news.google.com/newspapers?id=q0JWAAAAIBAJ&sjid=i-oDAAAAIBAJ&dq=tire%20pressure&pg=4713%2C3955360

 

[CapriRacer]

Originally Posted By: AstroTurf
Here are a couple of Real Pros...

Look at the advice they give Alice, IE see how the other half lives.

LOLz, Jim

http://news.google.com/newspapers?id=q0JWAAAAIBAJ&sjid=i-oDAAAAIBAJ&dq=tire%20pressure&pg=4713%2C3955360


I have taken Tom and Ray to task over much of their advice where tires are concerned. But this one is from 20 years ago! I'll bet they would answer it differently today!

 

[rpn453]

Originally Posted By: AstroTurf
Did you buy the summer set size as a performance upgrade? Rim specs?

Thanks for the story.

Jim


Both summer and winter rims are OEM with 6.5" width and 52.5 mm offset. The 17" alloys came with the car while the 16" rims are Mazda steelies. The "summer" tires I'm using are actually high-performance all-seasons. The tread of the Michelins is 1/2" wider than that of the OE Goodyears in the same size. I suspect that is why the Goodyears seemed to want a little higher pressure than the Michelins do.

 

[AstroTurf]

Originally Posted By: rpn453
Originally Posted By: AstroTurf
Did you buy the summer set size as a performance upgrade? Rim specs?

Thanks for the story.

Jim


Both summer and winter rims are OEM with 6.5" width and 52.5 mm offset. The 17" alloys came with the car while the 16" rims are Mazda steelies. The "summer" tires I'm using are actually high-performance all-seasons. The tread of the Michelins is 1/2" wider than that of the OE Goodyears in the same size. I suspect that is why the Goodyears seemed to want a little higher pressure than the Michelins do.


Thanks for the info.

It sounds like you are on the right track. Track days can be a lot of fun, plus you can learn a lot about your car. Keep us posted on your final dialed in psi.

Good Luck, Jim

 

[AstroTurf]

Well Fellers,

I have on this morning performed my 114th psi measurement on these tires. (in 50 days and 4,717 miles)

I have also settled on a cold psi that I will use throughout the life of the tires. (subject to tread depth measurements at 5,000 mile intervals)

My testing proved that at various cold pressures come various temperature increases. Measured by using the psi pressure increases after measured test drives.

To give you an idea of where my inflation pressures are at, although I said I would not reveal the actual inflation levels.

My tires are inflated over the tires sidewall pressure of 35 psi, Which is subjective, as in three different psi ratings on new passenger tires today...i.e. 35, 44, 51. Thanks Tire Manufacturers... Way to establish a standard, NOT.
The pressure increase over placard pressures are also very close to the way other Countries give a dual psi rating for cars based on speed and/or load. Thanks again Lazy American Car Manufacturers for being... LAZY.

So in conclusion... My tires are over tire sidewall psi, and over vehicle placard psi. But, not grossly over. They have been tuned and monitored by me, for my particular needs and application.

I can now rest and go back to my once a week Sunday Morning tire psi checks.

I will check in with pics and tread wear measurements at the 5,000 mile interval rotations.

Y'all Take Care and Be Safe, Jim

PS Please keep your tire inflation tuning stories coming. They are very similar to mine.

 

[CapriRacer]

AstroTurf,

I recognize a rant when I see one, but the one thing that would have been very interesting would have been the criteria you used to decide. You don't need to tell us what your starting point was, but it was terribly unclear how you decided on a final result.

 

[AstroTurf]

CapriRacer,

The Rant as you call it is from my displeasure with the industry for not giving us all the facts. Had we more info from them, this may not be such a dark subject.

My testing methods are as follows:
Start with the placard specs, Inflate and record psi throughout the test period, noting the cold, warm, and hot psis. Increase psi, and repeat. Monitoring hot psi measurements after a test drive while monitoring ambient temps. Continue until ride comfort is unacceptable, or until you feel that vehicle control has been degraded. Drop back to regain both comfort and control.

The end result for me has been a tire that runs cooler, lasts longer, and is above vehicle placard.

I do not advise any to follow blindly those that say: Inflate to sidewall max, Nor those that say do not inflate above placard.

Hope this helps, Jim

PS I once attended a great meeting of the worlds great tire and vehicle manufacturers. The only problem was that none of them spoke my language. Nor could any of them communicate with each other. So for all of the knowledge that was held in the room, No one had any greater benefit or knowledge than when they came.

Small measurable steps bear out the truth... Good or Bad.

 

[CapriRacer]

AstroTurf,

OK, this may seem a bit redundant on my part, but are you saying that your acceptance criteria was ride quality and vehicle control? - and that increased inflation pressure resulted in both being unacceptable at some elevated level - not necessarily at the same time?

 

[AstroTurf]

Capri Racer,

These tires that I conducted this set of tests on are an extremely comfortable. Unlike the last set that I just replaced.
These Tires never gave poor ride quality before the control degraded. Unlike the last set in which the ride quality degraded first.

So Yes, ride quality, vehicle control, along with monitoring psi levels for increase (heat), guided me to my now operating tire psi.

Hope it helps, Jim

 

[CapriRacer]

AstroTurf,

OK, so for one set of tires the ride comfort (I would call this ride harshness) was the determining factor, and for another set the vehicle control was the determining factor, plus something about - and this is just a guess - pressure build up.

2 questions:

1) Can you describe the thing about vehicle control that determined where the limit was?

2) Can you give me some insight into what it was about the pressure build up that influenced your decision?

 

[AstroTurf]

Capri Racer,

Sure, I will try.

1) As I progressed through small psi increases, there came a point when the vehicle control was more vague, had more under-steer than I was willing to accept. Understand that I have driven this vehicle for the last 2 1/2 years, logging more than 71,000 miles, so I know what is optimal and what is not. The psi at that level was not acceptable to me. I never reached a point of an uncomfortable ride with this tire.

2) An under inflated tire runs hotter, and an overinflated tire runs cooler. So, once again, I started with placard pressure and drove a test loop. Measuring the psi and ambient temps both before and after the test loop. I found that as I increased the tires cold psi, that the tires hot psi increases began to fall. When I reached the point of a drop off in vehicle control. I stopped the psi increases and reverted to the last satisfactory test loop scenario.

I hope this answers your questions, Jim

 

[Volvo_ST1]

How does exceeding the maximum sanctioned tire pressure specs affect liability? I am not only talking about the loss of liability insurance, but also personal liability due to negligence.