[Old Pa]

I've been running two sets of tires/wheels for summer and winter with good luck. This would be especially effective on your rear wheel drive Mustang. Winter tires are specialty items and virtually peel their own tread at higher temperatures. In snow and on ice, however, they are unbelievable. Bridgestone Blizzaks and Dunlop Winter M2s are the winter boots for the Maxima and Outback (respectively). For summer, I've had good luck the the Bridgestone RCOTs more aggressive models. You can get some good used steel rims for winter, sized to fit not more than a 60 series (you want some sidewall when the road is ugly and rough). If you stick with one set of all season, you will need more aggressive mud and snow performance to make a difference on a rear wheel drive vehicle. Tire Rack's website does a good job differentiating the individual tire models' performances. Watch your tire pressure when it's cold; you'll lose significant traction teeth if the temps bring you to low pressure. I run tire pressures within a pound or two of each tire's rated max; they seem to work the best when they're not falling off the bleedin' rims.

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[TWIFOSP]

For a pure summer tire for the street, you can hardly beat the falken azenis.

I also like the yokohama all weather z rated for err all weather.

Right now I run those, because they're cheap, and because I finally have dedicated track tires so don't need the azenis.

Oh, and please keep the racing off the street. I know everyone with a sport car has done it. Hell I've done it scores of times. But keep it off the street. Eventually the timeline for something bad happen will run out and you or someone you know. It's not worth it. I don't mean to be preachy... but you get the idea.

Anyway, back to tires!

 

[TheReaper]

I test tires for a living. Stay away from BFG. I run Eagle F1 GS-D3 on my 97 z28 6 speed with some mods. Excellent wet and dry traction with excellent wear and is quiet. Don't even think of running these tires in the snow, zero traction. For a winter tire look at Ultra Grip Ice, best winter tire in the industry. The TireRack is excellent for researcing tires, and great prices too.

Old Pa couldn't be more wrong running his tires at those pressures.

Remember tires don't makeup for a bad driver.

Edit for my horrible spelling

 

[TWIFOSP]

Well he was incorrect in the statement that low tire pressure will lower your traction. Lower tire pressure, so long as it doesn't bend your sidewall and cause a camber skew will actually increase tire traction. But not so much at low speeds. Which is the speed one is typically traveling in bad conditions.

THAT said, I think the point of his statement, was that low tire pressure is bad. And it's definitely bad in cold weather. Sidewall bending will cause tire cracking, especially in cold snowy weather.

I would not recommend a low pressure high sidwall combination in any normal application. I happen to use low pressure high sidewall for autocross when the course is set up for short sprints. But the increased traction is hardly worth the trade off you'll get by damaging your tires by running low pressure in the cold.

Also, Eagle F1s are a great tire, stock on the z06. However, the bang for your buck value is about null. I had a pair of dunlop sp8000s before they discontinued them, and they felt way better on the track than my previous F1s. Hell, I think when I was inbetween hoisers and decided to race on my Z rated yokohamas they performed fairly decent when compared to F1s. Not as good, but the price of the F1s wasn't worth the difference.

I still stand by the falken azenis as one of the stickiest tire you can buy for the street.

But for autocross, hoosiers FOR THE WIN!

 

[wallijonn]

Quote:

Originally Posted by Imyourzero I'm just concerned with being able to find something cheap that I won't have to dump a ton of money into. It's pretty easy to find 4WD beaters for $2-$4k but nearly all of them have over 100k miles on them, and even if the engine is still running strong I'm worried about having to sink money into things like gaskets, bushings, and other commonly neglected parts.

How many miles a week do you put on the car? When it comes to snow it once took me 8 hours to go 50 miles (blizzard of '78). I was driving a Pinto station wagon (bought because it went well in snow).

Today it would be a front wheel car. I drove a Subaru Golf for 5 years and had no problems. In PA we had a few 24" snow days where only SUVs were allowed on the road.

If they use salt on the road the last thing you want to do is drive your car on it. My Subaru Golf was so beat up by the salt that the whole frame needed replacing. It was one big rust spot when I got rid of it. (I drove it down to the junk yard and turned in my keys and registration. They sold it two days later.)

Ever lost your mind on driving on ice? It's not worth wrapping a Mustang around a tree.

When it comes to SUVs - Broncos IIs with a 6 cylinder were really bad. I had a Mitsubishi with a 4 banger. It got 20 mpg. It served me well for 5 years and then the electrical went crazy. My brother had a Pathfinder that just rusted away. (Cheap steel). My brother gave me a Honda Civic that its doors would freeze in ice. I had to use crow bars to open the doors. I no longer will buy a car where the door seals go through the roof.

I usually say that if you buy a used car or truck - be prepared to invest another $2500 the first year and $1000 a year thereafter for upkeep.

My brother buys his cars and SUVs because of looks. I buy a car or SUV because of the engine and drivetrain. He's had really bad luck with his SUVs and cars and he is amazed how many years I get out of mine. It's all the minset you go into a new car or truck. There are good deals out there. You just have to buy the right one. (My brother will never ever buy a car or truck in white. My other brother will not buy one in red. I cannot drive a green car.)

My brother was driving in a snow storm in Yonkers. There were tie ups everywhere. And some guy in a Corvette was out there. That guy was out of his mind.

If I heard that there was going to be more than 6 inches of snow I just wouldn't go into work. I drove my Miata once in the snow - 2 hours to go 5 miles. I think I have about 4 inches of clearance. My Golf had about 6 inches of cleanance. 8 inches of snow and I knew I would be stuck somewhere.

How the hell do people drive vans in the snow? And why isn't there a van that has front wheel drive or all wheel drive or 4 wheel drive drive?

If I lived in snow country I would have to buy a Suburu all wheel drive. If you're stuck in Idaho or North Dakota you'll most probably be driving a 4x4 pickup with oversized tires and a lifted body. There, 30 inches of snow is common.

So, how much room under the carriage? 8 inches? Live near any hills or have to drive up hills to get to your home? Chances are that you'll need 4 wheel drive then. Man, I remember helping some girl get up a hill by pushing it. That baby was just spinning its wheels. Not fun.

I say you'll need the most aggressive rain tire for your Mustang and a winter car with snow tires. I say forget racing type tires (especially the "Summer" tires) for your Mustang. I hope you have a three car garage with 3 sets of tires for the Mustang.

Maybe you should have bought a Suburu WRX...

Deep snow and torrential rain are the best times to test drive a car or truck.

 

[Old Pa]

Quote:

Originally Posted by TheReaper Old Pa couldn't be more wrong running his tires at those pressures.

1) I said I was running tires several pounds below the max cold pressure their manufactruers rated them for. Your comment is both ambiguous and less than useful. My experience and a bunch of folks in the industry say otherwise. 2) With modern high pressure auto tires, low tire pressure is much more of a problem than is pressure at the tire's rating. You don't have to look any further than the Explorer/Firestone debacle to learn this.
Quote:

Well he was incorrect in the statement that low tire pressure will lower your traction.

To the contrary, on a dedicated winter tire, running at low pressure will expand the contact patch and soften the sidewall; both adversely effect snow traction and handling. Running at full pressure (not overpressure) will maintain the maximum traction with the best contact patch for snow and ice. I've seen tires aired up to recommended pressures in heated garages go down 8 to 12 pounds after they chilled off in subzero temperatures. These are simply facts.

 

[wallijonn]

Quote:

Originally Posted by Old Pa I run tire pressures within a pound or two of each tire's rated max; they seem to work the best when they're not falling off the bleedin' rims.

So, which is it? Max or Min?

I think OldPa was saying that he inflates to within two pounds of maximum air pressure. The colder the air outside the more air pressure it will lose. Higher air pressures should also elevate the car an inch or so. Conversely lower air pressures will give you better traction but will also lower the car an inch or so.

I usually will run them at their suggested air pressures (listed inside the driver's side door well). Nah, I'm lying. My Miata suggests 26psi and I run mine at 30psi. Why? Because in the summer it'll lose 2 psi in 30 days. When I was living in PA and I heard there was a snow storm coming I would head to the gas station and make sure that they were pumped up to the right air pressure. And I always filled the gas trank with premium gas during the winter months - it always ran smoother. Here in Phoneix I do every other tankful in premium. (You gotta keep the engine clean).

 

[TWIFOSP]

Quote:

Originally Posted by Old Pa To the contrary, on a dedicated winter tire, running at low pressure will expand the contact patch and soften the sidewall; both adversely effect snow traction and handling. Running at full pressure (not overpressure) will maintain the maximum traction with the best contact patch for snow and ice. I've seen tires aired up to recommended pressures in heated garages go down 8 to 12 pounds after they chilled off in subzero temperatures. These are simply facts.

Increasing the contact patch to the road surface increases traction. But yes, not so in snow because the contact patch means jack if it's not contacting something it can apply friction to.

In general however, running lower pressure does 2 things to increase traction. Again, this is bad for snow because it will damage your sidewall. First it increases your contact patch. Secondly, at high speeds, the centrifugal force generated by your tires spinning will increase the inside air pressure. Again, not something that's going to happen in snowy weather as you won't be going fast. It also has the ability to improve handling because as you turn in, the tire expands to the outside of the weight shift, especially with an aggressive camber, and the tire flexing will improve the lateral grip.

Again, all a moot point in snow because the main factor in snow is getting the snow outside from under neat the tire and getting the rubber to meet the road.

 

[wallijonn]

I think both of you guys are agreeing - Old Pa said "adversely" and you reiterated with an explanation. After reading your quote I can undertand why Old Pa inflates to near maximum pressure - so that it will compensate for the loss of air pressure in sub zero weather.

The obvious answer is to make sure you inflate your tires outside and to check them 3 trimes a week when it really gets cold. (I can feel my hands freezing right now).

 

[Old Pa]

Quote:

Originally Posted by TWIFOSP Increasing the contact patch to the road surface increases traction. But yes, not so in snow because the contact patch means jack if it's not contacting something it can apply friction to.

On mud, snow, or ice, higher air pressure (but not higher than the tire manufacturers specification) increases traction and handling several ways. 1) With a smaller contact patch carrying the same vehicle weight, force per unit area is increased over a larger contact patch. 2) With proper pressure for the ambient operating environment, proper sidewall rigidity supports proper tire shoulder and tread operation within all aspects of the handling envelope (ie. squirm is reduced).

Quote:

at high speeds, the centrifugal force generated by your tires spinning will increase the inside air pressure.

Are you suggesting that independent of temperature fluctuations rapidly spinning pneumatic tires show significant increased air pressure from "centirfugal forces" on the pressurizing air within the tire?

Quote:

Again, all a moot point in snow because the main factor in snow is getting the snow outside from under neat(sic) the tire and getting the rubber to meet the road.

I don't know about your snow experiences in Austin, TX, but up North we know that for months of the winter on some roads there is no possibility of the tire meeting anything but snow and ice. It is within that environment that purpose built winter tires excell. Snow, compacted snow, and ice are the driving surfaces. There is no possiblity of syping these frozen materials from beneath the tire.

Please note that I have never suggested running a tire at a higher air pressure than is specified by its manufacturer on the tire sidewall.

 

[TWIFOSP]

Quote:

Originally Posted by Old Pa Are you suggesting that independent of temperature fluctuations rapidly spinning pneumatic tires show significant increased air pressure from "centirfugal forces" on the pressurizing air within the tire?

Absolutely.

Indy F1 cars have fairly low pressure in their tires. Around 18-20 PSI. This is when the car is racing however. When the car is being rolled around and not driving, the pressure can be as low as 10 psi, and when the car is moved at slow speeds, they literally have to spin burn the tires to get the pressure up.

This pressure is lowered 1. because the pressure increases that much when the tires get extremely hot at those speeds, and 2. the spinning force of the tire throws the lower pressure to the outside wall inflating the tire. It's more heat expansion than the spinning force, but it's part of the increase in PSI.

Think about a basic turbine based air compressor. It works by spinning a large turbine and "throwing" the air to the outsides of the circular wall. The air is compressed because it has no where else to go. In a tire, being spun at thousands of RPM the air is going to be forced against the sides of the tire.

 

[Old Pa]

Quote:

Originally Posted by TWIFOSP Absolutely. Indy F1 cars have fairly low pressure in their tires. Around 18-20 PSI. This is when the car is racing however. When the car is being rolled around and not driving, the pressure can be as low as 10 psi, and when the car is moved at slow speeds, they literally have to spin burn the tires to get the pressure up. This pressure is lowered 1. because the pressure increases that much when the tires get extremely hot at those speeds, and 2. the spinning force of the tire throws the lower pressure to the outside wall inflating the tire. It's more heat expansion than the spinning force, but it's part of the increase in PSI. Think about a basic turbine based air compressor. It works by spinning a large turbine and "throwing" the air to the outsides of the circular wall. The air is compressed because it has no where else to go. In a tire, being spun at thousands of RPM the air is going to be forced against the sides of the tire.

I understand the gas law problem and believe the changes in air pressure to be primarily (if not exclusively) thermodynamic. Racing tire compounds have to be warmed up to be effective; hence tire warmers, warm up laps, and burn outs. All of this is done to get tire compounds to their effective operating temperature ranges. Any significant increase in air pressurization pressure, while planned for, is a function of increased tire operating temperature, not centrifugal forces.

The comparison to the compressor of a jet engine is even more direct. You forgot to mention that the intake air is mixed with jet fuel and then burned while compressed to harness the fuel's energy in heat and increased burning volume to drive the compressor blades themselves while providing thrust. Jet engine turnbine speeds are many magnitudes that of a revolving vehicle tire, however, and the flow [atterns and pressures of air/fuel mixture through a jet engine do not equate to the static condition of pressurizing air within a pneumatic tire.

I believe that heat from flexation during tire operation rather than any centrifugal effect on the air spinning with the tire to be the cause of elevated pressure of the air within the tire.

 

[TWIFOSP]

Quote:

Originally Posted by Old Pa I understand the gas law problem and believe the changes in air pressure to be primarily (if not exclusively) thermodynamic. Racing tire compounds have to be warmed up to be effective; hence tire warmers, warm up laps, and burn outs. All of this is done to get tire compounds to their effective operating temperature ranges. Any significant increase in air pressurization pressure, while planned for, is a function of increased tire operating temperature, not centrifugal forces. The comparison to the compressor of a jet engine is even more direct. You forgot to mention that the intake air is mixed with jet fuel and then burned while compressed to harness the fuel's energy in heat and increased burning volume to drive the compressor blades themselves while providing thrust. Jet engine turnbine speeds are many magnitudes that of a revolving vehicle tire, however, and the flow [atterns and pressures of air/fuel mixture through a jet engine do not equate to the static condition of pressurizing air within a pneumatic tire. I believe that heat from flexation during tire operation rather than any centrifugal effect on the air spinning with the tire to be the cause of elevated pressure of the air within the tire.

I actually wasn't referring to an jet engine, but a regular air compressor. You don't need fuel and ignition to compress air. I tend to agree, they have nothing to do with eachother. It's probably a good thing I never brought that up. I didn't forget to mention anything, as they aren't mutually exclusive.

Several regular air compressors work this way, to compress air only, not to provide thrust. Water compressors too. They just sling air to the outside of a circular surface and it's forced to be compressed.

A turbo for a car engine works the same way (driven off of another turbine connected to compression side driven via exhaust gases).

Your dryer also does this, though it doesn't compress anything. When your dryer spins, the clothes are locked to the outside.

Think of those carnival rides where you stand in a cylinder and it rapidly spins and the floor drops out, and you're stuck to the wall.

Think of the motorcycle dare devels who drive fast around a sphere or cylinder and stick to the walls.

Enough examples?

Actually, most tires in F1 racing don't even use regular air, they use nitrogen to combat heat expansion and keep pressure solid. Of couse heat expansion still plays a very large role. But simple physics dictate that once you begin rotating an object, the forces will expand to the outside of the object. Even the tire slack that is caused by the lower pressure will be thrown to the outside, making the tire "fuller".

The main point of tire warmup isn't really pressure anyway, it's to heat the compound of the tire so it is sticky.

Anyhow, we've successfully derailed this thread by a significant amount so this will be my last post on this subject.

I concede the points concerning snow driving, as you're right, in Austin TX we don't get much

As far as tire pressure, remain skeptical if you like, doesn't bother me or the laws of physics

 

[Old Pa]

Quote:

Originally Posted by TWIFOSP Your dryer also does this, though it doesn't compress anything. When your dryer spins, the clothes are locked to the outside.

What about the dryer vent? Mighty hard to get clothes dry if it was a closed system. My dryer "tumbles". This is not your best analogy. Maybe you should go with the washer spin cycle. But we all understand centrifugal forces; we're just not buying they significantly change air inflation pressures at normal highway speeds.

Quote:

The main point of tire warmup isn't really pressure anyway, it's to heat the compound of the tire so it is sticky.

Which is what I said.

Quote:

As far as tire pressure, remain skeptical if you like, doesn't bother me or the laws of physics

Which are also not bothered when their names are mispronounced.

Attempted esotirica has a way of distracting.

So I'm pretty much here standing behind everything I've said up until now; buy appropriate tires for your purpose and fill them with enough air for their operating environment.

 

[apnk]

Quote:

Originally Posted by wallijonn If I lived in snow country I would have to buy a Suburu all wheel drive. If you're stuck in Idaho or North Dakota you'll most probably be driving a 4x4 pickup with oversized tires and a lifted body. There, 30 inches of snow is common.

Or a Jeep.

I have a AWD Jeep Grand Cherokee. I have some Bridgestone tires on it and they have sweet traction and long lives. I am not sure of their car tires though.