guys wat kinda tyre pressure you peeps running for street. Bearing in mind i do alot of "spirited" driving, hehehehe. Wats the optimum pressure without prematurely wearing out your tyres?

 

street: 36 PSI all the way around

track: 39 PSI all the way around

 

Tire pressures as compared front to rear:
Higher front = understeer
Even = neutral to oversteer
Higher rear = oversteer

The stock setup on the door jam is for understeer (usually safer on streets). Be careful with an even to rear higher bias on the street. If you don't know how to handle oversteer you will be surprised ! I experimented with all three setups in autocrosses. I used to like a "loose" rear (oversteer). But, I have been getting my fastests times with a tight rear, because at extreme turns in autocross, the car rotates anyway with the understeer setup.

 

id say go with the factory recommended 34 front 32 rear.

Boba- who adheres to what Honda recommends most times.

 

I will second that vote for Factory Recommended Pressures... Check the sticker on the inside of the door.

 

I'd say go with the factory recommended 35 front 33 rear.

These pressures seem to work well on the track as well as on the street.

nsxtasy - who hates to correct the great Boba-Fett, because he's usually right, so he double-checked in the owner's manual before posting this.

 

DOhhhhh!


Boba- who may be wrong again, but he has been drinking e .

 

I ran mine 32-33 all the way around, and it worked great. On my GSR, I ran the rears lower than the fronts (35-37F, 31-32R), but the R is much more ballanced, and works with less of a difference front to rear.

Pressure depends on the outside temp, and totally varies from tire to tire. On the 010's they have a very stiff sidewall, and you can get away with running less pressure on the street.

For track & Auto-X, you have to do a roll over test (tire not the car, or your dog) with some chalk to find out the correct pressure to run.

No matter what, it comes down to your personal preference.


[Modified by FBP_1171, 7:57 AM 6/22/2001]

 

Is that factory recommended?

I was running those pressures because they made the car feel really neutral. I may even run them like that at the next auto-x because I felt a lot better running that way...

I got my best times at TGP with that setup (even though they heated up on the track)... so I just like it now. Any danger of tire rolling over at auto-x on the sidewall with those pressures in the re 010's?


[Modified by Black R, 11:18 AM 6/22/2001]

 

I run 37 front and 35 rear for 205/15/50 RE730s.
The higher pressure helps for the lower profile of the tires compared to stock.
I tried the stock pressures on these tires and the car was very noisy and cornering did not feel as crisp.

 

Yes, those 15-series profiles are REALLY low profile. But the sidewall height isn't all that much lower, thanks to those 50-inch wheels.

 

I was running 30lbs on all 4 after getting my wheels rotated(I'm assuming acura changed the pressure?). I changed back to factory recommended a few weeks later, and the difference was pretty dramatic. I would imagine the factory setting keep the most tread of the ground, and the car is definatly netural in corners.

 

I usually find my tires are at low PSIs when the dealer returns the car. I guess they set it to the PSI on the door jamb when the tires are hot. I check the pressure when the tires are cold.
Answering the original question, I have my tires set to 37F, 35R. These are 195/55 Dunlop SP9000s. Setting them to 35/33 gives me more sidewall squirm/squeal than I want for spirited driving. The problem with this setting is that after two summers I can see the tread is more worn in the center coz the pressures are higher than they are supposed to be.

jmb

 

Jones,

It's not just those settings. I had the same tires (SP9000 195/55-15) set to the factory 35F/33R on the GS-R and they wore faster in the middle. Right now mine are on the treadbars in the middle, but not along the sides of the tread.

I'm not sure why this is. Maybe the SP9000 tread pattern just wears that way?

 

I usually run about 35 or so on the street. I never try and let it get any lower. I also tend to get a little better gas milage that way too.

James

 

No. The original post got it backwards.

The general rule (and the way I always remember it) is:

Higher pressure = better traction
Better traction in front (where the wheels turn) = oversteer

 

My original post is based off of what I learned autocrossing and from Pro's within my autocross region. Maybe there is a difference with RWD cars? But, from my recent experience, whenever I increased pressure in the rear, the car rotated easier. So I assumed this was due to decrease in traction. Nonetheless, after all of my experimenting with pressures, the best setup felt like higher in front, compared to rear. Here is an idea (if you have the time): Test the pressures yourselves. Tomorrow, find a safe turn/parking lot and run a different bias (f/r) and see what happens, understeer/oversteer/neutral. I am curious. Also, please post what pressures you ran and whether you are running a FWD or RWD car. After testing, my Kumho V700's seem to perform better (@80-90 degree air temp) cold set at 35/33. I used to run 40/40 but I like the lower pressures better.

P.S> this kind of debate I like, even though it may have been covered before. instead of all of this OT stuff

 

It's not any different between FWD and RWD, because the front tires steer the car in either setup. So it's always (theoretically) increased pressure in the FRONT = more oversteer.

I don't know why your experience was different. The only thing I can think of is that, beyond a certain point, if your pressures are very high, increasing pressure MAY decrease traction. But the general rule is in the other direction.

 

hang on...... less pressure = more traction, even tho the tyres sidewall will flex more, the ultimate grip is greater than a tyre that has more air pressure, vice versa......

this is up for debate, but its what ive always learned and known, even in my days of racing RC cars, same rules apply.


[Modified by N1 Spec, 6:41 AM 6/23/2001]

 

38...im serious...its the only way my tyres dont wear unevenly....god if you were spending $1200 every 3 months on tyres, youd take such measures also.

 

I normally run 35f/ 33r and today I tried out 35f / 35 f .. The car definitely rotated much easier with lift-throttle, but it was also easier to get it to understeer too. I guess it made it easier to rotate because I was able to get it to understeer at a lower speed at which point I can lift the throttle and induce oversteer.

 

Can someone then clear up the issue regarding oversteer & understeer, I think if the front tyres are underpressured, the car will trends to oversteer, is it right?

 

Everything I've heard contradicts this. Raise the rear tire pressure or increase the rear stiffness to oversteer more on the ITR. Plus, my experience has been that when I increase the rear pressure, the car rotates easier (sometimes too much), whether it be autocross or on the road course!

And, from a theory standpoint, lower pressure should produce better traction, no? The tire will conform more to the surface of the road and give a LARGER contact patch, since the size of the contact patch only has to do with the weight of the car and the tire pressure!

 

Lets also think about dragsters. The top fuel dragsters have like 5psi (ok, maybe not that low but it is low) in their rear tires. They seem to get better traction at lower pressures. Obviously the tires are designed for the super low pressures, but if higher pressures = more traction, then they would design tires for higher pressure. As I stated previously, my experience has always been higher pressures in the rear compared to pressures in the front created an oversteer situation within my car. This past autocross, a competitor with a rwd car was having traction problems, and he decided to increase his pressures for more traction. I thought that was the wrong thing to do, but I am definitely not an expert. I am not sure if it worked. Basically, the best thing to do will be to test different pressures with different car configurations (AWD, FWD, RWD and not worrying about front engine, mid-engined, rear engined, that would get to crazy).

 

Guys,

Here is my understanding based on these posts from the past and personal experience.

With a FWD, it's not necessarily more in the front or rear to get oversteer/understeer.

What I was told is to do this:

1) Set the front tire pressure so that the tires do not roll over too much. Using white shoe polish on the tire helps. **EDIT** then check the polish to see how far you rolled in a turn.
2) Once the front is not rolling over and it not too overinflated, you adjust the rears to dial in oversteer/understeer. More pressure makes the rear easier to turn=more oversteer=less traction.

This was a reversal of what I had always thought: run more pressure in front and less in the rear to get more oversteer. You could have more pressure in the front than the rear depending on your setup, but you do add pressure to the rear to get oversteer.

I think the traction to psi varies, for example, if you had 10 psi in the rears, you would prob get oversteer since there would be no traction. The contact patch would be large, but no pressure to hold car? I'm not sure why, but if you have a flat on your bike it gets all squirrely, lol.

If you have a ton of psi in the rear, it will also get looser, since you are getting away from the optimal contact patch (I guess).

So, I think you can generally say that you add psi to the end you want to rotate more, but it also works the opposite way at the extreme...

**EDIT The dragster does get better traction with low pressure, but it's a different type of tire and the traction is in a straight line. Picture your car with little/no tire pressure in the rear, it would be all wishy washy, probably because there is no sidewall to support the car??

Thoughts?

FB