You Need to Hook it Up! Part Two

By: Roger Hewson

Welcome back to class students. After reading the first installment of our mini-series on putting the power to the ground in your front-wheel-drive car, there should be a decent understanding of how the chassis on your FWD should be set up. In this installment we are going to get down to some of the simpler reasons you spin tires at the drag strip and how the wrong choice in tires will kill the way your car comes out of the hole.


We have all tried to go fast without decent tires at the track. Everyone has seen the “drag racer” with the EK Civic powered by a built B20 trying to get the power to the ground through a four-puck race clutch, Type R gears with no LSD and 17 inch Volk TE37 wheels. The pricey wheels are wrapped with a set of 215/40/17 Champro tires bought for $30 at Cooters Discount Alignment and Rubber and he or she can’t figure out why the car spins the tires through fourth gear no matter how much smoke they make in the burnout box. Hmm…


So what’s going on here? What can be done to get our fictitious friend mentioned above flying down the track? Like we said in Part One, for every action, there is a reaction. Some simple problem solving should help out our knowledge-challenged buddy. Let’s try to figure out what he is doing wrong here.


Bigger sidewalls on a higher profile tire act as a cushion.

First of all, the tire is the most important thing there is when it comes to putting power to the ground. Who hasn’t seen a tire commercial going on and on like a broken record about the four little patches which separate you from the road? Anyone who knows anything about cars will tell you tires are critical to traction just like feet are critical to walking.


To find out more we went right to the source and spoke two of the most respected tire companies when it comes to drag racing; Mickey Thompson and BFGoodrich. We pretty much got the exact same stories from their tire engineers regarding what works and what doesn’t. Jason Moulton of Mickey Thompson and Oscar Pereda of BFGoodrich gave us the skinny on what the right meats are to use on your FWD car and why.


Both Pereda and Moulton recommend changing to a wheel and tire combination that gives you as much sidewall as possible. “The sidewall of the tire absorbs power when you launch the car aggressively,” says Pereda. “This goes for a dedicated drag tire or just a regular street tire.” The bigger sidewalls on a higher profile tire act as a cushion and soften the shock to the contact patch of the tire helping to prevent wheel spin. The larger the sidewall, the more cushion area there is to absorb shock allowing a harder launch or more power to be applied.


This is especially true when it comes to a dedicated drag tire like the BF Goodrich Drag Radial or the Mickey Thompson Sportsman because their sidewalls are designed to absorb the energy which causes wheel spin by being softer so they wrinkle at lower air pressures, making them stretch like a rubber band. “The smaller the wheel the more sidewall you can run and the more elastic the tire is going to be when launched,” says Moulton. “But you can only go so small with a wheel and so big with the sidewall before changing how tall the tire is and messing with the gearing or running into fitment or stability issues,” says Moulton. So how do we know what tire size and type to run?


Before we figure out what size we want, we need to know what type of tire we are going to run, normally either a bias ply or radial. The terms bias ply and radial have to do with the construction of the tire and how the belts of the tires are wound and assembled. The construction of the bias ply tire is much more pliable than the radial because the arrangement of the nylon belts which give the tire it’s shape and strength are woven at 30 or 40 degree angles. When a Radial tire is made the nylon (or steel) belting is woven in a radial pattern and there are usually more layers woven in for more strength.


Because the bias ply tire is so much more pliable high horsepower cars like to run them because they tend to expand and grow taller at high speeds, allowing the car to run more mph at the end of the track. They also tend to wrinkle much easier at lower pressures than radials do without deformation of the contact patch. The downside is because of how pliable they are they tend to walk more meaning the car will dance side to side while driving because the sidewalls are not stiff enough to prevent the car from moving around. This can be a bit unsettling at over 100 miles per hour in a FWD car considering these are the wheels you steer with. One person told me the best thing to do is just hang on and hold the wheel straight. Radials, because of their sturdier construction are much more street friendly which comes into play if you don’t have the bankroll to buy a wheel/tire combo solely for the track.


BFGoodrich developed a special compound for their FWD Drag Radial, making the tire more controllable

Running a radial like the BFGoodrich Drag Radial on the street would feel no different than having a typical radial tire on your car. When you get to the track the difference can be felt with almost slick-like traction out of the hole. Theory would tell you the radial construction of the BFGoodrich tire would put it at a disadvantage on the starting line against a bias ply tire, but it’s not completely true. Paul Efantis would pull the front tires off the ground regularly when he was driving his Toyota Supra in 2003.


“Progressiveness is one of the keys to the success of the BFGoodrich Drag Radial,” says Pereda. “A tire has to break loose progressively or you’re not going to be able to control it.” BFGoodrich developed a special compound for their FWD Drag Radial which made the tire extra controllable after breaking loose and realized it would work well on both front and rear-wheel-drive tires and improved the entire Drag Radial line. “Our tires are very gentle when they let go, easy to control,” says Pereda.


What all of this means to our EK buddy is a few things. If he wants to keep the big Volk wheels and run a 17-inch BFGoodrich Drag Radial he can. Running a smaller wheel is a problem for some people who need the clearance because of big brake setups. The low profile tire is not going to hook nearly as well as a tire on a 13 or 14 inch wheel with a ton of sidewall, but it will be a huge step in the right direction. When the Drag Radials break loose they will do so with plenty of warning and will be very controllable. It still will not allow the EK Civic driver to come out of the hole with the authority they might want to, but they can lay into the throttle much earlier then was possible before.


The tire size is related to the goal of the racer.

“The tire size is related to the goal of the racer,” says Moulton. “If you are bracket
racing, use the tallest, widest tire you can fit for consistency and if you are
heads-up racing, use the smallest tire that will get the job done.” So we need to look at how often the car is raced, and what kind of racing our little friend does. Remember this is just an example. You can apply it to whatever you drive, just change the variables to suit your needs.


A car with modest power doesn’t need a huge tire like the turbo cars run. An ideal setup if the car does not have a set of big brakes is a set of 13-inch wheels with the shortest, fattest tires allowed without running into wheel spin problems on the starting line. Like we mentioned above how well the car is going to hook up depends on how serious the owner of the car is willing to get. A set of 215/40/17 Drag Radials will have some serious bite, but they will not give you the slingshot launch of a pair of tall BFGoodrich Drag Radials or Mickey Thompson ET Streets mounted on a set of 13 or 14 inch wheels would have. Now how about those clutches and LSDs?


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