Why tire pressure is so important...

[iluvmacs]

I noticed this on my way back from work today. I had the tires pumped up to 38 psi because I like the feel and you get better gas mileage that way. What I didn't realize (duh) is that when the wheel balloons out from the center, all the force from turning is acting on a smaller area, essentially wearing it out faster.

This is from 3 months of "spirited driving" with 2 of those months at too high tire pressure.

Notice that the rear tires, although still at 38 psi show little signs of wear. That has a lot to do with the weight distribution of a front drive car, my driving habits, etc.

I have the tires set at 35 psi right now. I'll rotate them if I ever get out to a track day at beaverun or nelson ledges. If anyone knows the "optimum" pressure setting (balance between contact patch size and sidewall flex) I'd like to know it.

 

[tonkabui]

i'm not sure about the stock tires, but dave is running 39 front left and 37 for the rest on his goodyear eagle f1's. all those right hand turns really beat your front left tire to crap. turn 10 at beaverun is brutal on tires. have fun! oh yeah, the time he got was 1:22, i got 1:23 just to give you an idea of what we were running our first time out. dave just came back from a track day and got 1:20 when the track was dry.

as for daily, i left mine at 32 for normal driving, 35 for long freeway drives and 38 for spirited driving. i feathered the edges, so i'm not sure why yours didn't.

 

[iluvmacs]

what do you mean "feathered" the edges?

the problem I have is that normal driving for me is "spirited". I used to have a crappy car so i'm taking advantage of the protege.

 

[Douggie]

Don't see anything wrong with your tires in those pictures. The treads in the center belt is very shallow anyways. I run 36 psi ever since I had my car. Got 30K miles out of them.

 

[Action Jackson]

Not to knock you but are you sure you're cornering hard enough? I don't see any chunking on the tires shoulders. j/k.

But I can see that the middle is more worn than the sides.

As for optimum tire pressures for the track on the stockers. I ran crazy pressures and I found that 35 front and 33 rears worked well if I didn't want the rear end to rotate out.

If I set them even F=R, then I can lift throttle oversteer.

At one track day, I decided to adjust the pressures until I liked the control of the car.

Know what they were?

The next day they were 32/32 cold.

However these stockers could not last more than say 4 to 6 hard laps for me.

If you are bringing your car to the track, use other tires. But otherwise inflate them to at least 36 psi F/R and then use a good tire pressure gauge and in small increments lower max 1 psi at a time.

 

[iluvmacs]

I got a good deal on a set of 15" rims I had planned on using for winter tires. I don't know if I can come up with another set for racing tires. I know eventually I need some though.

Do you really get that few laps from the stock tires? That sucks...

Douggie: I was curious about that, but the difference from right to left bothered me. The rears still look brand new, no signs of wear to the naked eye. I thought that they might wear a little more evenly.

 

[Douggie]

I got a good deal on a set of 15" rims I had planned on using for winter tires. I don't know if I can come up with another set for racing tires. I know eventually I need some though.

Do you really get that few laps from the stock tires? That sucks...

Douggie: I was curious about that, but the difference from right to left bothered me. The rears still look brand new, no signs of wear to the naked eye. I thought that they might wear a little more evenly.

There are 4 main big grooves and each of them has a wear indicator (that little bump). Compare them and see if you really have more wear in the center.

And remember that the fronts DO wear out faster than the rears.

 

[tonkabui]

I got a good deal on a set of 15" rims I had planned on using for winter tires. I don't know if I can come up with another set for racing tires. I know eventually I need some though.

Do you really get that few laps from the stock tires? That sucks...

Douggie: I was curious about that, but the difference from right to left bothered me. The rears still look brand new, no signs of wear to the naked eye. I thought that they might wear a little more evenly.

dave's car with 3 beaverun track days on it had probably more wear than the 10K miles of driving he did on them. i'm not sure about the stockers cause they're not sticky, so they slide around a lot. i remember the jetta in my class that was squealing all over the track on his stock tires. his tires were not happy at all. i wouldn't doubt that the harder compound and its sliding around so much more will wear out the tires faster.

 

[shinzen]

within about 5k miles I shredded my stock dunlops on the front- just crap tires IMHO- my kumhos have been way better, and cheaper- if you need a couple of cheap stockers, though- my rears are still in great shape and I'll sell em' cheap

 

[JOS3]

i dont know why so many people have had problems with the stock tires (dunno). my p5 is 2 years old and my tires are still in good condition. i dont drive like a grandma but i dalso dont drive like a ******* moron. i do tend to spin the tires from a stop when it rains, but that is my only complaint. ive driven through 2 winters with them and have never slid *knocks on wood.* i think people just need to be a little more careful. i usually kepp my tires inflated between 32-35 psi

 

[shinzen]

I can't believe you haven't slid jay- I used the stockers for one winter here in CO and they were horrid- and in raing they hydroplane like crazy- damn near died cause of them. I don't drive like a moron, but I am a bit spirited in the corners- and the results were mentioned already...

 

[Douggie]

i dont know why so many people have had problems with the stock tires (dunno). my p5 is 2 years old and my tires are still in good condition. i dont drive like a grandma but i dalso dont drive like a ******* moron. i do tend to spin the tires from a stop when it rains, but that is my only complaint. ive driven through 2 winters with them and have never slid *knocks on wood.* i think people just need to be a little more careful. i usually kepp my tires inflated between 32-35 psi

It depends on how demanding you are on your tires. Some people bring the stock dumlops for track and needless to say they suck in that situation (what did u expect from all season tires? ). I'd say for normal daily fast driving in dry conditions, they aren't THAT bad.

In rain, they DO suck. In snow it's barely okay. So in those situations, I just go easy on the gas pedal.

Will I buy those again? That's a definite NO. Actually I don't think anyone in this forum said that they would buy these again, so maybe that equates to the tire being sucky?

Remember that if you do a lot of high speed corners, you should up the PSI so that you have less tire flex and don't tear up the edges as much.

 

[iluvmacs]

My take on rain is that these tires are great. They have the tendency to hydroplane but the wet grip has been amazing compared to what I was used to.

Don't know about the snow. I'll find out soon enough if i can't get a set of snow tires.

 

[shinzen]

I think douggie has the best point there- they aren't the worst tires I have ever had, but for replacement, at $105 apiece dunlop can kiss it- kumhos are $80 apiece and way outperform them in every category- or for an even better summer tire the falkens are a great way to go....

 

[iluvmacs]

Agreed. I wouldn't pay $105 for those tires any day.

thanks for the posts. Is there any better place to buy tires than tirerack.com?

 

[Brian MP5T]

...
This is from 3 months of "spirited driving" with 2 of those months at too high tire pressure....

How is this for "SPIRITED DRIVING" ???

 

[Brian MP5T]

within about 5k miles I shredded my stock dunlops on the front- just crap tires IMHO- my kumhos have been way better, and cheaper- if you need a couple of cheap stockers, though- my rears are still in great shape and I'll sell em' cheap

The Dunlops are a good tire but I would not replace the OEM rubber when they wore out. There are some really great 15" tires out there for way less.

 

[Douggie]

Agreed. I wouldn't pay $105 for those tires any day.

thanks for the posts. Is there any better place to buy tires than tirerack.com?

Yeah, if the dumblops are down to like $60 a tire, then we MIGHT think about it. LOL

check out discounttiredirect.com as well. They have free shipping. They sell the Falken Ziex's at a pretty decent price.

 

[Rism]

mine are at at 29psi is that a good level for daily driving?

 

[mazdaowner123]

I run 35 psi front and rear for daily driving. 32 psi just has too much sidewall flex. You can really feel the 3psi difference, it makes the steering feel a LOT better. This is on bridgestone potenza s-03's though.

~brian