[Editor’s Note: This article originally appeared in the May 2015 issue of Grassroots Motorsports, back when Bob Woodman Tires was still in business.]
Though the time period “avenue tire” is stretched fairly skinny in terms of the present crop of R-compound DOT monitor and autocross tires, there’s nonetheless an enormous distinction between these almost bald gumballs and true racing slicks.
Racing slicks are usually lighter, stickier and extra responsive than their street-bred counterparts. In any case, slicks don’t have to fulfill DOT necessities for the issues that make a avenue tire civil. Due to falling costs and elevated availability—for each new tires in addition to takeoffs—we’re additionally seeing extra slicks in our world than ever earlier than.
Regardless of the efficiency benefit supplied by racing slicks, many drivers are nonetheless apprehensive about making the leap—even when their racing guidelines permit it.
Certainly, we had been in the same state of affairs not too long ago after we added a Formulation 500 automobile to our venture roster. Along with folks not considering we had been cool anymore, we confronted the problem of tuning and driving a automobile on true race slicks moderately than the DOT rubber we’d been utilizing for 3 many years. Racing slicks not solely look totally different, however they’re a very distinctive animal, proper?
For some recommendation, we turned to Bob Woodman of Bob Woodman Tires. It’s no coincidence that he and the enterprise share a reputation, and it’s no coincidence that he’s a wealth of data as regards to the variations between DOT stickies and slicks. He sells and providers just about something spherical, black and rubber that an individual can race on. Right here’s a few of his recommendation.
Tip 1: Harness Warmth
Each DOT tires and slicks want a specific amount of tire temperature to work correctly. Nevertheless, slicks are a lot much less forgiving of too little or an excessive amount of warmth. Every producer has a desired working vary for specific tire compounds.
DOT tires are usually slightly extra forgiving when chilly—particularly in autocross compounds, that are designed to work at near-ambient ranges of warmth. Slicks, alternatively, don’t work properly in any respect till they attain their minimal working temp.
Each slicks and DOT tires endure a scarcity of grip when overheated, however slicks may also endure structural harm after they get too scorching. This overheating can dramatically shorten the lifetime of the tire and even result in untimely failure.
Tip 2: Apply Strain
Correct tire pressures are at all times important, however simply as with tire temps, slicks are a lot much less forgiving of improper pressures than DOT tires. (It’s possible you’ll be seeing a theme right here.)
This distinction is due partially to how racing slicks are constructed, but in addition to the truth that a slick-shod automobile usually sports activities very excessive spring and damper charges, making for a really stiff chassis. Tire sidewall deflection then turns into a measurable issue within the whole spring charge, making strain that rather more necessary.
Woodman additionally cautions that he typically sees tire pressures which are too low. As with an excessive amount of warmth, this will result in catastrophe. Higher to start out excessive and work your approach down than the opposite approach round.
Tip 3: Monitor Tire Temperatures
Most of what you discovered about tire tuning applies to slicks: You’ll nonetheless be searching for even tire temps throughout the tread face when tuning the suspension.
One caveat, although: Some radial-construction slicks produce their greatest grip when displaying slightly extra warmth on the within edges. Excessive temps within the middle of the tread normally imply tire pressures are too excessive, whereas increased temps on one edge or the opposite are normally the operate of wheel camber. This logic applies to each DOT tires and slicks, by the way in which.
Tip 4: Anticipate Extra Grip—to a Level
Slicks might be much less forgiving on monitor, too, however not within the methods you may assume. Slicks typically have a really excessive contact patch-to-weight ratio, so lateral grip will definitely be drastically improved.
Since you’re working at increased cornering ranges, nevertheless, breakaway can appear that rather more abrupt. Nevertheless, most good fashionable slicks are moderately predictable when stored inside their excellent working temperatures.
Braking efficiency can really be the largest distinction between DOT tires and slicks. Regardless of their extra grip, slicks normally have a a lot decrease weight than equally sized DOT tires, giving them much less rotational inertia and making brake lockup much less predictable. Non-ABS vehicles will generally tend to flat-spot slicks, particularly with an inexperienced driver simply making the transition from DOT tires.
Tip 5: Observe Tire Put on
Identical to DOT tires, tire put on removes rubber from the tread floor of slicks. Consequently, the tread will get thinner with use.
Most slicks have molded-in dimples that make tire put on measurable, nevertheless. This characteristic is extraordinarily beneficial for monitoring their well being.
Like uneven tire temps, uneven put on throughout the tread face can point out the necessity for chassis changes. Put on charge may also offer you a sign of total tire well being. For instance, our mild Formulation 500 will in all probability by no means put on a set of tires all the way down to the twine earlier than they get heat-cycled to the purpose the place they’re not efficient.
Put on charges must be constant all through the aggressive lifetime of the tire. If you happen to discover a tire not carrying as a lot over a given quantity of monitor time, meaning it’s getting tougher and due to this fact much less sticky.
Tip 6: Beef Up the Chassis
If all you do is slap on some slicks, you’re not getting almost the complete profit. Due to their extremely grippy nature, slicks like a strong, predictable platform. Additionally, due to that very same grip, you’ll be placing masses into your chassis that it by no means skilled on DOT tires. So chassis preparation turns into extremely necessary, because you need to get rid of as many variables as attainable.
In a production-based automobile, this normally means bushings are your weak hyperlink—they usually’ll in all probability trigger essentially the most frustration while you’re making the swap. The grip from slicks can deflect OEM bushings far previous the purpose the place they will keep secure alignment. In reality, slicks can push OEM bushings far sufficient that they danger failure or structural breakdown. A change to slicks must also imply a change away from rubber bushings as a lot as your guidelines bundle permits.
Since slicks permit for such excessive grip ranges and fast response instances, chances are high you’ll must retune the chassis to take full benefit of all this new tire functionality. Fortunately, the identical methods you used to tune your chassis on DOT tires—measuring tire temps, recording section instances and utilizing knowledge acquisition—switch over properly to slicks.
Simply perceive the significance of a strong platform and develop from there to seek out the fitting setup. It could be so simple as altering springs and shock settings, or it might take plenty of tuning. Lengthy story brief: This shouldn’t be a mid-season change. Make the soar to slicks when you possibly can commit time to correct testing.
Tip 7: Correctly Retailer Your Slicks
Don’t wreck these fancy slicks between races. Improper storage is among the most vital limiting components of their shelf life.
Two of the largest killers of rubber are UV mild and ozone. After all, you possibly can’t do a lot about these components at an outside occasion, however away from the monitor it’s a unique story. Slicks must be saved at reasonable temperatures and away from UV mild and ozone.
Place slicks in thick, black, plastic rubbish luggage to cut back UV publicity, and preserve them away from ozone-generating units like arc welders and heavy-duty electrical motors. By no means permit slicks to freeze—in the event that they do, it is best to in all probability retire them.
