Tire Pressure!!!

[CharlesW]

I had an interesting experience yesterday. I brought a bent wheel in for repair and I`m running Michelin Pilot Sports on it. The repair technician mentioned to me that I am running underinflated pressures. He pointed out that I had my pressures at the sill OEM recommended pressures - 32 front and 35 rear. He indicated the Pilot Sports max PSI is 50 and I should bump mine up to about 42. He further stated the door sill placard recommends the OEM tire pressures and said I am running non OEM tires now with a higher recommended pressure setting. The benefits according the tire tech is it is more forgiving if I hit another pothole or whatever caused the initial damage. Plus he said I`ll get better gas mileage.

When I got home I pumped them up to 40.

The repair technician might very well be right, but,,,, I think I would get a few other opinions before I made that large of an adjustment. Overinflation carries some drawbacks, too.

Disadvantages of Overinflation

An overinflated tire is stiff and unyielding and the size of its footprint in contact with the road is reduced. If a vehicle`s tires are overinflated by 6 psi, they could be damaged more easily when encountering potholes or debris in the road, as well as experience irregular tread wear. Higher inflated tires cannot isolate road irregularities as well causing the vehicle to ride harsher and transmit more noise into its interior. However, higher inflation pressures reduce rolling resistance slightly and typically provide a slight improvement in steering response and cornering stability. This is why participants who use street tires in autocrosses, track events and road races run higher than normal inflation pressures.

[GearHead_1]

I had an interesting experience yesterday. I brought a bent wheel in for repair and I`m running Michelin Pilot Sports on it. The repair technician mentioned to me that I am running underinflated pressures. He pointed out that I had my pressures at the sill OEM recommended pressures - 32 front and 35 rear. He indicated the Pilot Sports max PSI is 50 and I should bump mine up to about 42. He further stated the door sill placard recommends the OEM tire pressures and said I am running non OEM tires now with a higher recommended pressure setting. The benefits according the tire tech is it is more forgiving if I hit another pothole or whatever caused the initial damage. Plus he said I`ll get better gas mileage.

When I got home I pumped them up to 40.

Your technician is incorrect, when a tire is manufactured it can be installed on anyone of 50 different models of vehicles. Different vehicles have different load capacities as well as Gross Vehicle Weights. The tire is designed to be adjustable to any of these different vehicles needs. This is as long as you can accomplish the vehicles needs and not inflate the tire past it maximum capacity. The manufacturer of the vehicle on the other hand knows what it will take to meet the vehicles needs with respect to load capacity, handling and braking. The number the car manufacturer gives you is the one to use, this of course is not an absolute and can be adjusted a couple of lbs. one way or the other and several pounds to accommodate and increased load.

If you pump the tire to a higher level you may actually experience slightly better fuel economy but you will have a harsher ride and experience significantly increased tire wear. The tire technician is correct in stating that the sidewall will be less likely to give way to bend a rim with more air in it. This however should be the exception rather than the rule. Hopefully you`re not hitting pot holes and curbs frequently. As far as the OEM thing goes it doesn`t matter as long as the tire on the vehicle meets the vehicles minimum speed rating (H, V, Z etc.), the vehicle`s weight doesn`t increase and the requirements don`t change. Should you happen to be driving a vehicle that you load heavily a truck for instance you can increase the tire pressure to better accommodate the load at that time but don`t go past the maximum inflation pressure on the tire. I`ve seen and sold a lot of tires from a managers eyes, (hundreds of thousands). We hate having to make a tire adjustment and give money back if we don`t have to. I`m interested in seeing the customer get everything they can from a tire. Take what I say for what it`s worth absolutely nothing.

I just went back and reread what Charles had posted. The TireRack statement is very well said.

[blk45]

As usual, good points by Charles and GH.

I owned a speed shop for 4 years and upgrading wheels was one of the most common things that we did. I spoke to multiple tire manufacturers and asked them for their recommendations for adjusting tire pressure when we were using non-OEM rims/tires, as almost everyone would opt for wider tires. Every one of them told me to stick with the stock pressures recommended by the car manufacturer. The tire supports the same weight. The car doesn`t get any heavier. As mentioned, the "max" tire pressure enables the tire to be used for multiple applications, or if the vehicle is to be loaded down for a trip, etc.

The only exception that we made, (as previously mentioned) was if someone was running an extremely small sidewall, then the inflation pressures were increased to try and prevent rim damage. The customer was informed of the options and the affects associated with them and then made a decision based on the info that we provided to them. We never made the choice for them.

[RobertP]

Another thing that almost everyone forgets is to make sure that the spare tire is always up to the correct pressure, it would really suck to get a flat tire, only to find out that the spare is flat as well.

I check my tire pressure every week on all of our cars, driven daily or not, I make it a habit along with checking all of the fluids.

[gewb]

What if the couple hundred or so regular DC users, members and lurkers, made it our mission to regularly check the vehicles of our family members, elderly neighbors, parents, and anyone else who is close to us? Toss a tire gauge in your detailing stuff and do your customers a favor.

So sad, what a waste.

I took on your suggestion a few years ago. I routinely inform people of their tire pressure when I`m fueling my car. I`ll even volunteer to properly inflate their tires for them at the station - some thank me, others just get a glazed look.

While I will not get out of my car at a stop light to inform someone of low tires, I often pull up to their side, roll down my window and inform them of the condition.

I probably average one or two of these situations a week.

Regards,
GEWB

[GearHead_1]

While I will not get out of my car at a stop light to inform someone of low tires, I often pull up to their side, roll down my window and inform them of the condition.

I do this also. Once I came across a lady laden with forthcoming child as well as a car full of kids. I actually had her pull over on the side of the freeway and changed her tire for her. The rim was literally cutting the sidewall out of the tire, it was loosing air as I changed it. I gave her a business card to one of the stores in my district to get a replacement tire. I don`t know if she went there or not. Welcome to DC Gewb.

[gewb]

Welcome to DC Gewb.

Thanks. I`ve been a long time lurker but I had to chime in about this topic.

Regards,
GEWB

[blk45]

Thanks. I`ve been a long time lurker but I had to chime in about this topic.

Regards,
GEWB

Thanks for doing so. We would gladly welcome your input on other topics as well!

[Pander5]

Not meant to threadjack but thanks Charles, gearhead and Eric. I respect your opinions and experience and I`m reevaluating my tire pressures. No need to prematurely wear $300 tires. Back to stock PSI tonight!

[GearHead_1]

No need to prematurely wear $300 tires.

Amen!

[Ronkh]

Since ther wasn`t a better place to put this.

I just got new shuz !!

[GearHead_1]

Mmmm... me and Bibendum like Pilots.

[GearHead_1]

Mmmm... Bibendum and I like Pilots.

[Ronkh]

Mmmm... Bibendum and I like Pilots.

I`ve never been a fan of michilen, I always liked bridgestone (go figure since mich owns bridge). But these are supposed to be something reall really special.

Too bad I wont get to find out for a while. Raining real bad and will for eh next 4-5 days at least. As well as it will take about 500 miles to clear the release agent/coating. Then I`ll know.

these are the new a/s PLUS model.

[9D4E420]

You will absolutely love those tires. A friend of mine has them and says they are great all around tires.