I'm going to get my H1 car aligned today for VIR, and was looking for suggestions from guys (or girls) who have run a similar car on Hoosiers before. I'm new to the world of Hoosiers, but I think I remember hearing that the old ones loved a lot of negative camber. Does the same hold true for the new ones?

Last year I was running - 2.5 camber all around, o toe rear, 1/16th" (each) toe out in the front. Of course I was never sure if it should have been 1/16" total toe out, or 1/16" toe out per side, but total just seemed too small to do anything.

Any thoughts?


Matt


Modified by speedracer33 at 9:59 AM 7/23/2004

 

Got a pyrometer?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grumpy &raquo;</TD></TR><TR><TD CLASS="quote">Got a pyrometer?</TD></TR></TABLE>

Nope. I'm just looking for a good starting point right now. Oh, and an alignment that won't shred my Hoosiers again!

 

Same as before with a little less in the rear. Maybe 2.

Alot depends on how stiff the car is. If you have minimal body roll, then you need less negative camber. If the car pitches over, you might need as high as 3 in the front.

 

Ask to borrow mine at the track, if you'd like.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Catch 22 &raquo;</TD></TR><TR><TD CLASS="quote">Same as before with a little less in the rear. Maybe 2.

Alot depends on how stiff the car is. If you have minimal body roll, then you need less negative camber. If the car pitches over, you might need as high as 3 in the front.

</TD></TR></TABLE>

Thanks for the reply Scott. Right now I'm running 600lb fronts, with 800lb rears on a car that weighs 2320 including driver. Not a whole lot of roll, BUT when I had to run the 225/50/16 tires in the rear at Summit, they did rub a little on the fender lip (already rolled back) under heavy cornering, so there is definately *some* roll.

Grumpy - thanks for the offer, I just might take you up on that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by speedracer33 &raquo;</TD></TR><TR><TD CLASS="quote">they did rub a little on the fender lip (already rolled back) under heavy cornering, so there is definately *some* roll.</TD></TR></TABLE>

IMO that's because you're using 16 inch wheels.

The pyro will tell you everything. Very useful data.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by krshultz &raquo;</TD></TR><TR><TD CLASS="quote">

IMO that's because you're using 16 inch wheels.</TD></TR></TABLE>

If you don't mind humoring a mechanically inept driver, what makes you say this? Lack of tread flex due to the larger diameter wheel?

 

Fitment. That's a big, tall tire compared to what used to be on the car way back when it was stock.

 

Yo Matt
http://www.hoosierracingtire.com/rrtire.htm




TIRE CARE TIPS
FOR R3S04 & A3S04 TIRES
Printable Version

The R3S04 and A3S04 have been developed to improve wear and consistency without any sacrifice of performance. In many cases, the performance will even improve over previous models. The '04 tire models are an evolution in the continuing effort to provide the best tire for racers.

- Tire Break-In Procedure
- Tire Temperature Recommendations
- Chassis Setup Recommendations
- Tire Pressure Recommendations
- Things to Consider

Tire Break-In Procedure
Proper break-in will not affect initial performance but will increase the competitive life of the tire.

The procedure can be broken down into phases.

1st phase: The initial run
2nd phase: The length of the time the tire is allowed to "cure"

The Initial Run
The first laps for the tire are critical for setting up the durability and competitive life. The first session should consist of 10-15 minutes of running. The early part of the session should be run at an easy pace, with the speed gradually increased until the end of the session. The final lap should be run at the fastest possible speed. The intent is to achieve maximum tire temp on the last lap. At this point the car should be brought in and the tires allowed to cool at a normal rate. Optimally, the tires should be removed or have the car jacked up during this cooling.

During this process, the inflation pressure should be 3-5 psi higher than you would normally use. The best progression would have the driver taking 3-5 laps to accomplish this break-in. Each lap should be approximately 2-4 seconds a lap faster than the previous lap. The goal is to have the tire temp as high as possible on the last lap without "shocking" the tire during the warm up laps. In essence, no wheelspin, late braking, or sliding. The last lap should be at, or very close, the maximum possible temperature.

"Cure" Time
After completing the initial run phase, the length of time the tire is allowed to set is possibly more important. The barest minimum for this process to be beneficial is 24 hours. (Not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again.

Proper tire management is a difficult process. To accomplish this almost always requires a second set of wheels. The payoff is greatly increased competitive tire life.

Following the recommended break-in procedure will require a lot of planning to make it work. The benefits to doing it right include greatly increased tire life as well as consistent performance and durability under stress. Please make an effort to educate your team on the importance of this. It can save you a lot of money.

Tire Temperature Recommendations
For best performance the expected temperature range will vary from track to track. Generally, optimum traction will be generated when the pit lane temps show 180-200 degrees for R3S04 tires. The A3S04 tire typically runs best at 120-140 degrees. Note: Use of static infra-red pyrometers is an inaccurate method to monitor tire temps.

Chassis Setup Recommendations
For optimum performance the Hoosier P-Metric radial tires require about 3 degrees of camber. There will be a trade off in maximum performance to maximize wear. Generally, 1/2 degrees less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.

The Hoosier tires typically offer better performance with spring/shock rates higher than previous brands you may have run.

Tire Pressure Recommendations
Hoosier tires typically require higher pressures than other brands. Autocross applications require higher ranges of pressure; road racing tends toward the lower end of the recommended pressures.

Reference the following chart for suggested pressures:

Vehicle size
Recommended Hot Pressure
Cold Pressure

1800-2200 lbs.
39-42
30-36

2200-2600 lbs.
40-43
31-37

2600-3000 lbs.
42-46
32-37

over 3000 lbs.
43-48
32-38


Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.

One characteristic of the Hoosier P-Metric radial tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure may improve the "feel" of the tire however it will also lower the performance and increase the wear on the tire, particularly on the outside tread edge.

The above chart is a general recommendation which is intended for a standard configuration vehicle (i.e. front engine, rear wheel drive). Factors which can radically affect your pressure set up would include front wheel drive, independent rear suspension, rear engine, McPherson vs. control arm front suspension.

Front Wheel Drive
Vehicles configured with FWD are probably the most difficult application for a tire setup. The combination of steering, braking and accelerating on the front tires, combined with higher corner weights for the front positions produce a harsh environment for the tire. These vehicles will typically have a strut type of suspension which limits camber gain. All these factors result in conditions which require the tire do more work than a simple chart for pressures can accommodate.

In severe cases front tire pressures for FWD vehicles can run in the 48-52 psi (hot). In cases where the tire size is limited to a relatively small tire, the required pressure can run even higher. The front to rear pressure differential on FWD cars can have extreme ranges of inflation, depending on the driver preference, suspension tuning, and track configuration.

Independent rear suspension
With IRS and proper geometry up front, tire pressures can be reduced from the recommendations listed above. When there is adequate camber gain and good roll control, the Hoosier radial tire will perform very well at the reduced air pressure. This results in a bigger "sweet spot" and easier control at the limit.

When tuning at reduced pressures use the following formula to determine the minimum safe pressure: Divide the total vehicle weight, including fuel and driver, by 100 to arrive at the minimum safe pressure. Example: Your car weighs 2750 lbs. as raced. The minimum safe (cold) pressure is 27.5 psi.

Extreme care should be taken when tuning at reduced pressure. Tire damage can occur that is not visible to external inspection.

Vehicles equipped with independent rear suspension (IRS) have a distinct advantage over non-IRS cars when using radial tires. This is true for two reasons. First, it is possible to setup some amount of static negative camber on IRS suspensions, if needed. Second, the IRS geometry can provide the proper camber gain to achieve the dynamic camber needed for a radial tire. This is a great benefit because it then becomes possible to better address front tire grip when the rear of the car can be optimized closer to the tire's potential.
THINGS TO CONSIDER
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use.

Due to extremely light construction, Hoosier tires have a much lower polar moment than other radial tires. This translates to a very low rotational mass, which is a good thing for performance applications. The down side to this feature is that the tires do not resist "spikes" in braking force as well as a heavier tire might. As a result, there is a tendency for drivers to "flatspot" a tire the first time really getting to the limit. Vehicles equipped with ABS will benefit from its use. If you do not use ABS it is recommended that you make an effort to minimize stabbing the brakes until you have some experience with the feel of the tire under hard braking.

The light construction also provides less protection from impact damage and punctures. Off course excursions or running over debris on the track will likely result in tire damage.

The tires are not directional. Once some wear has occurred it may be desirable to flip the tire on the wheel in order to even out the wear and maximize tire life.

Wheel Widths
Wheel width dramatically affects wear and performance of the Hoosier P-Metric radial tires.

There is about a one inch window of optimum width. The trick is to figure out that window. A good rule of thumb to use for determining proper width is to use the tread width of the tire. Measure the tread width. Plus or minus 1/2 inch from the tread dimension will indicate the proper rim sizing. It is possible to use narrower wheels, but at a sacrifice to shoulder wear and cornering power.

"Measured" rim vs. "Recommended" rim
In our printed product catalog and on our website tire specifications you will see two columns of information regarding rim dimensions. In most cases, the "measured rim" and the "recommended rim" will be the same. However in the case of DOT tires, the information may appear contradictory.

The reason for the differences lies in the Department of Transportation requirements for publishing tire dimensions on any tire that carries a DOT certification. Each tire size has a specific rim that must be used when taking measurements for tire comparison. This is intended to allow consumers a consistent way to compare tire sizes between brands.

With respect to the Hoosier P-Metric line, the recommended rim size will typically be wider than the DOT standardized wheel.

The fact that a tire will "fit" on a rim is not an indication that it will work effectively in that condition. Radial tires are extremely sensitive to wheel widths. The performance characteristics of the tire can change significantly within the recommended range of application. Mounting a tire on a rim that is outside of the recommendation is not a good idea.

Driving Style/Braking
Driving style has also shown to significantly effect tire wear. Drivers who achieve their speed by "tossing" the car run the risk of increased tire wear. Radial tires develop their highest cornering power at relatively low slip angles. Smooth, tidy driving yields faster lap times and better tire wear.

The braking feel of the Hoosier R3S04 tire is very vague at the threshold. This is particularly true for "sticker" tires. Drivers need to develop a sensitivity for the limits under braking. This takes time and practice. Failure to apply this will result in flatspotted tires.

Particular care needs to be taken when selecting brake pad compounds. It is possible to have a pad that is too agressive. This will make it very difficult to develop good braking fell for threshold braking.

Rain Tires
The Hoosier D.O.T. Radial tires are extremely good in dry conditions, however they do not make very good wet weather tires. Having dedicated rain tires available will be necessary for your team to be properly prepared. Hoosier makes a D.O.T. approved bias-ply tire called a "Dirt Stocker" that has been proven to be far superior to any competitors tire as long as it is a steady "wet" condition. Check with your Hoosier representative for size availability.

Hoosier Racing Tire also offers a D.O.T. Radial Wet tire. This tire has a molded tread of symmetrical design. Check the product catalog for the available sizes. The compound for these tires is intended for wet weather use only.

Hoosier also offers a non-D.O.T. radial rain tire based directly on the P-Metric R3S04 tire. The tread depth is 8/32" and the pattern is the same tread design found on the R3S04. They have been allowed in BMW Club racing and many other sports car clubs as well. Mounting instructions can be found in the “Road Racing FAQ” section of the website. The list of available sizes can be found in the "road racing/tire specs” section of our website.

When using rain tires, always increase your starting air pressure 2-4 psi over your dry tire pressures.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamSlowdotOrg &raquo;</TD></TR><TR><TD CLASS="quote">Fitment. That's a big, tall tire compared to what used to be on the car way back when it was stock. </TD></TR></TABLE>

185/60/14 = 71.4" circumference, 22.7" diameter

205/45/16 = 73.1" circumference, 23.3" diameter (2.3% taller than stock)

225/50/16 = 78.1" circumference, 24.9" diameter (9.3% taller than stock)


The 225 is definately taller than stock, but I thought that maybe Karl was referring to something deeper having to do with flex since he specifically blamed the wheel size instead of the tire size. I probably just looked too far into it.

The Kumho 710 will be available in 215/40/16 - which is only .1% taller.

 

SPORTS CAR D.O.T. - RADIAL (A3S04 & R3S04)


Item
Number Tire Size Tread
Pattern Tread
Width Approx.
Dia
Circ Recom.
Rim Measured
Rim * Section
Width A3S04
Auto
Cross R3S04
Road Race
46300 P185/60ZR-13 M* 6.5" 21.6" 68" 6-7" 5.5" 7.6" X
46305 P205/60ZR-13 M* 8.0" 22.7" 71.4" 7-8" 6.0" 9.0" X
46307 P225/45ZR-13 M* 8.6" 20.7" 65" 8-9" 7.5" 9.0" X X
46310 P225/50ZR-13 M* 8.3" 21.8" 68.5" 8-9" 7.0" 9.1" X X
46400 P195/55ZR-14 M* 6.8" 22.7" 71.2" 6-7" 6.0" 7.6" X
46405 P205/55ZR-14 M* 8.0" 22.6" 71.0" 7-8" 6.5" 8.6" X X
46410 P205/60ZR-14 M* 7.3" 23.5" 73.8" 7-8" 6.0" 8.1" X
46415 P225/50ZR-14 M* 8.8" 22.8" 71.5" 7-9" 7.0" 9.3" X X
46500 P205/50ZR-15 M* 8.0" 22.8" 71.5" 6-8" 6.5" 8.6" X X
46505 P215/60ZR-15 M* 7.7" 24.9" 78.4" 7-8" 6.5" 9.2" X
46510 P225/45ZR-15 M* 8.8" 22.8" 71.5" 7-9" 7.5" 9.6" X X
46515 P225/50ZR-15 M* 8.2" 23.4" 73.6" 7-9" 7.0" 9.0" X
46520 P225/55ZR-15 M* 8.7" 24.5" 77.1" 7-9" 7.0" 9.4" X
46525 P245/50ZR-15 M* 9.2" 24.4" 76.7" 7-9" 8.0" 10.2" X
46540 P275/50ZR-15 M* 10.3" 25.3" 79.5" 8.0-10.5" 8.5" 11.3" X
46600 P205/45ZR-16 M* 8.1" 22.8" 71.5" 6-8" 7.0" 8.6" X X
46610 P225/50ZR-16 M* 8.8" 24.6" 77.3" 7-9" 7.0" 9.5" X X
46615 P245/45ZR-16 M* 9.2" 24.4" 76.7" 7-9" 8.0" 10.2" X X
46620 P255/50ZR-16 M* 9.8" 25.8" 81.0" 8-10" 8.0" 10.7" X X
46630 P275/45ZR-16 M* 10.3" 25.3" 79.5" 8.0-10.5" 9.0" 11.2" X X
46700 P205/40ZR-17 M* 8.1" 22.8" 71.5" 6-8" 7.0" 8.6" X
46710 P225/45ZR-17 M* 8.8" 24.6" 77.3" 8-9" 7.5" 9.5" X X
46715 P245/40ZR-17 M* 9.2" 24.5" 76.8" 8.5-9.5" 8.0" 10.2" X X
46720 P245/45ZR-17 M* 9.3" 25.3" 79.5" 8.5-9.5" 8.0" 9.8" X
46725 P255/45ZR-17 M* 9.8" 25.8" 81.5" 9-10" 8.5" 10.7" X
46730 P275/40ZR-17 M* 10.3" 25.2" 79.1" 9-11" 9.5" 11.2" X X
46735 P315/35ZR-17 M* 11.4" 25.6" 80.4" 10.5-12.0" 11.0" 12.6" X X
46740 P335/35ZR-17 M* 12.4" 25.6" 80.4" 11.5"-13.0" 12.0" 13.6" X X
46810 P225/40ZR-18 M* 8.8" 24.6" 77.3" 7.5-9.0" 8.0" 9.5" X X
46820 P245/35ZR-18 M* 9.1" 24.4" 76.7" 8.5-9.5" 8.0" 9.8" X X
46825 P245/40ZR-18 M* 9.3" 25.3" 79.6" 8.5-9.5" 9.0" 10.5" X
46835 P275/35ZR-18 M* 10.3" 25.2" 79.1" 9.5-11.0" 9.5" 11.2" X X
46840 P285/30ZR-18 M* 10.9" 24.6" 77.3" 10.5-11.5" 10.0" 11.4" X X
46845 P305/30ZR-18 M* 11.4" 25.6" 80.4" 11-12" 11.0" 12.4" X X
46850 P335/30ZR-18 M* 12.4" 25.6" 80.4" 12-13" 12" 13.5" X X

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Catch 22 &raquo;</TD></TR><TR><TD CLASS="quote">Alot depends on how stiff the car is. If you have minimal body roll, then you need less negative camber. </TD></TR></TABLE>
This doesn't seem right to me. These cars gain negative camber as they get lower no? I'd think the more pliant the suspension, the more negative camber you gain in cornering, the less static negative camber you'd want to begin with. Conversely, it seems to me that the stiffest examples of these cars run very large amounts of negative camber.

 

Who is doing your alignment?

 

A FWD car with a lower roll center, and less body roll, will throw less "weight" over the outside shoulder of the outside front tire.

When I had 400/600lb springs on my Integra I was at 2.75 degrees negative in the front and still seeing outside 1/3 temperatures too high and excess shoulder wear. When I went to 800/1200 suddenly I had slightly high INSIDE front tire temps and more wear on the inside of the front tires. Reducing the negative camber to 2.5 on the LF and 2.3 on the RF solved the problem beautifully. The reduction in camber also improved straight line braking.

Dunno, I'm not an engineer or anything so I could be completely wrong. Once again I'm just doing what the pyrometer and the wear bars says is right &lt;shrug&gt;.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 6ghatch &raquo;</TD></TR><TR><TD CLASS="quote">Who is doing your alignment? </TD></TR></TABLE>

Sometimes I forget you live around the corner from me. I take it down to Valley Forge Auto in Broomall. They mount all my tires for me, and do the alignments. They take really good care of me there.

 

Best way to see if you are running enough camber is by a pyrometer like others said. However, if your alignment is slightly off, your outside or inside of the tires may get affected by it.

I always though that the more body roll a car has in a corner, the more negative camber the suspension geometry generates. That's why if you lower a car, you'll obtain more negative camber.

It would be interesting for someone to explain the truth behind this.

 

I think its the difference between static and dynamic suspension loading. This is the reason (as it was explained to me by a certain guru) that progressive rate springs aren't ideal for the track. Once the suspension compresses enough to add the camber and the springs "firm up" the damage is already done (so to speak) as the car is already weight transferred and pitched over.
Same goes for camber and tire wear if I'm understanding it correctly. A softer setup may add more camber as the suspension compresses, but by the time its working you're already all loaded up on the outside of the outside front tire.

But I could be completely wrong.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Catch 22 &raquo;</TD></TR><TR><TD CLASS="quote">A softer setup may add more camber as the suspension compresses, but by the time its working you're already all loaded up on the outside of the outside front tire.</TD></TR></TABLE>

Ok, that does make sense.

 

we don't gain as much negative camber in bump as we loose in roll. someone else might actually have real numbers here, but the rough approximation i use is 1/8" bump on the outside front per degree of roll. -1 degree of camber gain in pure bump of 1". say the ouside front compresses 1" in roll, that would equate to roughly 8* of chassis roll with a total camber loss of +7*. this is real rough and dirty and doesn't include a lot of other factors, but it's close.

nate

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">we don't gain as much negative camber in bump as we loose in roll. someone else might actually have real numbers here, but the rough approximation i use is 1/8" bump on the outside front per degree of roll. -1 degree of camber gain in pure bump of 1". say the ouside front compresses 1" in roll, that would equate to roughly 8* of chassis roll with a total camber loss of +7*. this is real rough and dirty and doesn't include a lot of other factors, but it's close.
</TD></TR></TABLE>

So exactly what I said, just with engineerese added.

Where's Rinde? I'm sure he can muddy things up really well for us.

 

I am surprised. If you gave me two identical Civics/Teggies the only difference being twice the spring on one of them, I'd suggest more camber on the stiffly sprung one. I don't know the semantics, just would be my stab. I do wonder if your pyrometer readings are taking into account the changes of bolt-in roll-bar to welded 8pt cage or from non-LSD to LSD - cannot exactly remember when you went to the stiffer springs - do recall Tom taking tire temp readings at Kershaw on the cage+lsd+stiffer setup.

 

Yes, that weekend at CMP was the 2nd outing on the new suspension (the first was a month earlier at VIR where you and Bookler handed me my *** because God himself couldn't have made that car turn) and Tom was helping point things in the right direction. The previous year the car DID have the welded cage and LSD, but was still on the softer springs and smaller rear bar.

That was when it was decided that I needed to reduce front camber. Inside temps and wear were high and the car was pushing on corner exit. This was with 800f/1200r and a 22mm rear bar. Less camber made the front tire temps look much better and improved cornering. Later the 24mm adjustable rear bar was added and the car got pretty damned good.

I have noticed (just visually) that the SWC cars seem to be running less camber this year with the RA1s than they did with the street tires last year. But I'll admit that they still seem to be pretty high (3ish is my guess) and very stiffly sprung. Maybe this is a function of not really caring about tire wear???
Just guessing here, Maybe we should quiz Chris D. on this at the next race. He's still the car boss for Shauna M. AFAIK and knew Hemmingson's car nose to tail, so he's been intimate with both the TS and RA setups.

 

Typical Honda:

Set the Static Camber to Zero (for discussions sake only).

Compress the front of the car - the camber goes negative.

Roll the car - the outside wheel camber goes postive, and the inside wheel goes negative.

So you set your static camber to give some small negative camber at the terminal dynamic roll position.

Stiffer car may reasonably be presumed to require less static negative camber.

But, as others have said, let your tires temps tell you what they want.

Scott, who resents the imputation that I would muddy things up, but appreciates the expectation that I would do it well...