You’ve spent all week tuning the car to prepare for the big race. Managing practice time and expensive practice tires is an important part of race weekend preparation. Practice usually centers on race set up and long runs. But, soon it will be time to qualify. During practice your team feels they have the car dialed in for race conditions and the driver reports the car feels great on long runs. Everyone on the team is happy as the consensus is that you have a good race set up for the car.
To get the most of practice and in race adjustments a good tire specialist is a must. JOES Racing Products Sales Manager and Gene Price Motorsports Tire Specialist Robert Osaki is a multi-championship winner. Rob brings the right tools to the track and meticulously cares for tire sets to 1/10 pound accuracy.
Since the car is fast and the competition in the pit area is staring at their stopwatches when your car is on the track, your team is confident that when the green drops that the car will be in contention for the win. In practice the car is fast on fresh rubber and when the “new” comes off the rubber the car is still fast in comparison to the competition. The race set up has been tweaked to find every ounce of comfortable speed.
Preparations begin for qualifying and a new competition begins. A fast car in practice is grand, but it is amazing how much can change during a qualifying run. You can only win the race if your qualifying time is fast enough to make the show – a front row start certainly helps your odds of winning.
Measuring corner speed helps to determine if qualifying tricks are increasing your corner speed. If you are scuffing qualifying tires in qualifying trim it is essential to record corner times and compare the corner time results to corner speed from practice laps in race trim.
At a big race, there are 40 cars and only 28 will make the A-main. Even with a car that grabs attention on practice time sheets – a good qualifying effort is needed to make the show. Fast practice laps mean nothing when the green waves for 2 laps of white knuckle driving to lay down a number to get you in the show. A fast car in practice that doesn't qualify well is insanely disappointing. A green, white, checker for qualifying is intense and getting the most from qualifying takes the work of an entire team supported by clean and comfortable laps from your driver.
Replacing the practice set with qualifying sticker tires comes with risk. Bolting on a set of sticker tires will add speed to your well-tuned car – or so it is hoped. New qualifying tires should bring you more speed on the qualifying clock, but often the car is tuned so well on good practice rubber that too often something is lost when new qualifying tires are bolted on. Sometimes the change in the balance of the car is changed by new rubber and added speed that you hoped for from a new set over and above the practice set is lost in that unknown space where the single socks that come out of your Washer and Dryer are found.
During practice – the practice set has had plenty of runs and the stagger and tire pressures have multiple opportunities to be set to perfection. Now comes the sticker set - fresh off the truck and you have one shot at getting the pressure and sizes right to match the balance built with your practice session tires.
Over the years, I utilized a few tricks that helped ensure a good qualifying effort when the rules or race conditions required a new set of tires for qualifying. Often, rules allowed for scuffing the sticker tires which is the perfect time to test how the car would react in taped up in qualifying trim.
How you deal with tires and adjustments for qualifying is up to much debate and each crew chief has their own bag of tricks for Late Model Qualifying trim.
Matching up the tire sets from practice to qualifying is critical. Unfortunately, when you have a practice set and a qualifying/race set it is not always possible to match up the sizes exactly between your practice and race set. It has always been my philosophy that you can’t stretch tires to make them bigger – they are what they are from the factory and the size is determined at the time of manufacture. Too often teams measure tires after they over inflate them hoping they will grow to get the need stagger. While cold, the excessive pressure used to stretch tires does seem to make tires grow. But, then the tire gets hot and the anticipated growth in size from “stretching” disappears as it is an illusion and the balloon effect shrinks to the factory size as soon as operating temperature is reached. Often teams get got in this mistake. It is my belief that with bias ply tires that you have a two pound window to adjust size. If you can’t match sets up with 2 pounds plus or minus of tire pressure then you need to go to the tire truck and get the right size from the factory. Two pounds is the absolute maximum variation to adjust stagger as more than that changes spring rates far too much – I prefer matching practice pressures exactly and strive to stay within only a one pound variation.
If the practice set and qualifying/race set are different sizes at each corner then it is a good idea (mandatory) to drag out the scales and adjust the cross weight to equal the practice set cross weight. Two pounds of pressure changes wedge more than you think – just add two pounds the next time you weigh your car and watch the scale numbers go nuts.
Purging the air out of tires 3 times is a proven amount to get the most air out of the tires and replace it with moisture free nitrogen which limits heat induced pressure growth. A purge tool helps to drain air while preventing air from re-entering tires that have been purged with nitrogen.
Now it is time to decide how much nitrogen to put in the tires for the 2 lap qualifying run. Science and witchcraft come into play. Your practice tires were measured hot after a 10 or 15 lap run and they had time to grow to full pressure from heat buildup. The full pressure needs to be carefully recorded so you can have an idea of how much nitrogen pressure to run for your qualifying session.
Since qualifying is generally just two laps, I would be aggressive with adding pressure for qualifying runs as it was my goal to build heat fast. Ideally, qualifying starting pressure would be enough to get the tires “too hot” and pressure build up goes past ideal right at the exit of turn 4 as the car is headed for the checker. My goal would be to have all four tires come in at one additional pound than hot practice pressures. For me, this meant sending the car out with plenty of nitrogen pressure and the qualifying starting pressure would be only one pound less than my “hot” practice pressures – each team should experiment, but since it is a two lap run then adding pressure is a must.
A quality tire gauge that measures in 1/10th pound increments will help your team to make fine pressure adjustments to create repeatable speed.
Once the new qualifying set is matched up and the car has been re-scaled then the sway bar load can be adjusted to mirror your proven practice set up. Careful tracking of sway bar load is needed and re-setting the sway bar for a perfect match was mandatory with my cars that sat on the pole. The more notes taken with the practice set increases the odds that speed will be gained when new tires are bolted on for qualifying. Depending on the tendency of the car on a given day, I often added a touch of sway bar pre-load for qualifying to keep the car stable for the driver. I would vary the amount and add ¼ turn, a half turn or maybe even a full turn of sway bar pre-load. Other times I would just leave the sway bar the same as used in practice.
A quality sway bar mounting system makes it easy to add turns of sway bar preload as needed. You can put in load quickly and return it exactly to your baseline by keeping good notes.
Another “trick” to build quick qualifying tire heat in the LF is to add a ¼” bump washer on the LF tie rod end. For race set ups I run .004 to .008 bump out on the LF. A ¼” Bump shim adds bump steer – the extra grip from sticker tires cover the excessive bump from my race set up and the added bump action helps to get heat in the LF tire quickly – since it is a two lap run I have found that this little trick helps the car to cut in the middle for qualifying by getting heat into the LF quickly. I pre-measure the toe change from the ¼” bump shim installation in the shop so I know exactly how far to adjust the tire rod length saving time and ensuring I can get back to my race set up toe adjustment quickly. By doing the work in the shop – I save time at the track and am easily able to add the ¼” LF bump shim for a quick qualifying run. Your team may only want to add a 1/8” bump shim – trial and error work fine for this speed secret.
Adding a bump washer to create excess bump steer on the LF can build quick heat to help the LF stick during a qualifying run.
During qualifying, I know the driver is going to leave it all out there and the driver is counting on the car to stick. To allow for the aggressive qualifying run I add 1 turn of front brake for qualifying as an insurance policy preventing the car from becoming loose in as the driver piles the car deep in the corners for qualifying. A little goes a long way and if you go too far with this insurance policy then you face making the car brake tight due to adding too much front brake. The idea is to add just a little as you know the driver is going to drive harder in a 2 lap run as compare to the smooth rhythm utilized in practice sessions.
Brake Balance adjusters with ball detents allow your crew to adjust the brake balance in quarter turn increments. Sometimes adding just a half turn of front brake helps the car for the aggressive laps turned in by top drivers.
In addition to adding a little extra bump to the LF, I also toe out the front tires more for qualifying stability. I typically only run 1/32 or 1/16th of toe out for a race set up. For qualifying, I up the toe out to 1/8” on larger tracks and maybe 3/16” on small tracks. The added toe out creates stability for a two lap run and helps to build tire heat quickly.
Adding small amount of negative camber at the RF coupled with an extra amount of Positive Camber on the LF will help the car turn for 2 laps – just throw in a 1/16th shim as you want to add a little everywhere verses going nuts with one qualifying adjustment. The added camber would burn up the tires on a long run, but stickers will cut better for a two lap qualifying run.
Pulling the front bumper cover out as far as the rules allow (and then some) on the front side of the front tires gives you added down force at the front of the car. Down force always outweighs drag on tracks 1 mile and under. Adjustable fender braces make for an easy adjustment if your rules allow it. Stretch out the nose as far as you can to plant the nose.
Utilizing Adjustable fender braces allows your team to quickly pull out the nose flare in front of the front tires – the extra down force helps the front stick when new tires tighten up the car on a qualifying run. You can also pull in the quarter panels a small amount behind the rear tires to help the car slip through the air during qualifying.
To stick the nose taping off the front grill, brake openings and any ducts that cool the rear end or driver are a good idea. As much tape as possible is the rule with one giant exception. Short track teams run the same engine for many weeks if not all year. The teams on TV can bolt in new engines faster than you can change underwear. If you tape off the front so much that the car spits out water in a two lap qualifying run you have gone too far. Overheating the engine even once is not a good trade – be sure that enough air gets to the radiator for cooling. The small amount of cool air you let in the front will not slow your car down enough to risk engine overheating – let a little air in the grill opening. You can experiment with leaving the bottom of the grill open 1” or so and compare how the car reacts compared to leaving a 1” opening at the top of the grill. An opening at the bottom of the grill will pull in more air than an opening at the top of the grill.
All the above qualifying tricks help the front tires to stick. Go too far with these small adjustments and the car can become loose. Experience, testing and good note taking tell you which tracks are loose or tight for qualifying. Adjustments must consider the track characteristics so some of the tips have to be toned down for tendencies of a given track. Common sense and moderation go a long way here.
Extra front grip for qualifying gives driver the ability to turn the car under the hard driving needed to get in the show. New tires often tighten up the car so adjustments that keep the front tires digging into the track can make sense. Testing while scuffing a sticker set is really the best way to find out and these ideas should be added into your program. Every time sticker tires go on it is a good time to test the effects of qualifying trim. Confidence gained on a test run in qualifying trim will help your driver lay down the best number when it matters most.
To balance the ideas you used to plant the front tires you can use your adjustable rear spoiler supports to stand up the rear spoiler 2 or 3 degrees. The rear spoiler does more than most people think so just a few degrees of extra spoiler angle will help compensate for the front qualifying adjustments helping you to balance the extremes used for a two lap run. The idea is to stretch several adjustments to the limit due to the quick run. It pays to pre-set all of these suggestions in the shop and test them whenever you switch from good practice tires to a new set that can be scuffed in preparation for qualifying.
Twisting the spoiler supports to add rear spoiler angle can add needed rear down force for qualifying to keep the car in balance with the adjustments made in the front.
On small tracks such as quarter mile tracks – there is little reason to run a full load of fuel in a 22 gallon fuel cell. The fuel tank is up high and behind the axle. Moving the fuel weight into lower lead weight mounted low is a speed secret that really works well. If you don’t need 22 gallons to finish the race then lead in the low in the car will increase speed. There is no need to be a hero and you can run several gallons of extra fuel so you never risk running out. That said – you can move a bunch of swinging weight that is up high and behind the axle and use lead mounted low to increase the adjustability of your car. If you always run on a small ¼ mile track and only run 50 lap races then permanently installing a small tank will make your car more adjustable and will move swinging weight into lead blocks lowering your center of gravity. Safety first always prevails so if you run a full size tank on a light fuel load then always install approved bladder foam manufactured by fuel cell companies to fill the area created by a reduced fuel load. Consult your fuel cell manufacture and install approved materials.
These ideas are just suggestions – use a few of them or all of them. You can tone the suggestions down or get more aggressive based on your driver, track, car and local rules. Better yet, you can think of all the tiny improvements that will work with sticker tires for a two lap qualifying run. Those that drive the limit of aggressive adjustments will make gains in qualifying speed. Those that go too far will change the balance negatively and qualifying in practice trim could have worked out better. The teams that use tricks to climb the speed chart will find the secret to write your name at the top of the pole.
Go Forward-Move Ahead
Jeff Butcher
3/5/13
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