When talking about drag racing tires, the front tires are often discounted with being nothing more than along for the ride. Despite this stigma, there’s quite a bit of testing and development that goes into making frontrunners that are up to the grueling task of running over 250 mph. Mickey Thompson Performance Wheels and Tires has dedicated many years of time and effort to guarantee their wide range of front tires appeal to a verify of track-goers and the weekend street warriors.
Bearing in mind that Mickey Thompson produces such a wide range of tires, it can become a bit daunting to figure out what set of skinnies are appropriate for your particular combination. With the help of Tom Kundrik of Mickey Thompson, we sift through the under-the-radar science of front tires and hit on the different features of both radial and bias-ply front runners out there.
Something that gets brought up regularly, when talking about mixing radial and bias-ply tires, is the misconception that you can’t run bias-ply tires in the rear and radials tires in the front. In our chat with Kundrik, he weighed in on this particular topic.
The complete lineup of Mickey Thompson front runners are made in the U.S.A., with the expectation of their Dragster ET Fronts, which are manufactured in England.
If you’re looking to use a set of radial rears and a set of bias-ply tires on the front this perfectly acceptable as long you have a matching set on each individual axle, and vice versa”- Tommy Kundrick
“If you’re looking to use a set of radial rears and bias-ply tires on the front, this is perfectly acceptable as long you have a matching set on each individual front and rear axle, and vice versa,” Kundrik explains. “This misconception started back in the day, when you just had bias-ply, and radial tires were just coming into the marketplace; it would be commonplace to see someone with a radial tire switching out to a bias-ply without changing out the corresponding tire on the opposing axle , and that’s when you started to see a problem. For example, every Radial vs. The World car out there is running ET Front style bias-ply tires in conjunction with a set of ET Street Radial Pros in the rear.”
Adjusting Reaction Time With Tire Size And Air Pressure
“Increasing air pressure in the front tires can improve reaction times while decreasing pressure will increase the tire’s footprint on the starting line, which will result in a diminished response time of the car, “Kundrik says. “A lot of NHRA footbrake class racers will utilize this to further dial in their reaction time. I’ve witnessed Comp Eliminator racers on the starting line with the front tires almost flat, to keep from going red or yanking the tires out of the beams.”
While Mickey Thompson does not recommend this, a lot of racers have utilized this method to make last minute adjustments to their tuneup. M/T suggests their front runners be run at around 35 psi, dropping the pressure below this will result in a cupping of the tire, as it runs on the sidewall instead of the tread, which will inevitably affect the structural integrity of the tire.
Drag racers have continuously modulated tire pressure in order to adjust a vehicle’s reaction times during qualifying and in competition, as it is an effective means of altering how the car will react and perform.
The same size tire can be made to appear larger or smaller by adjusting the tire pressure. Less air gives the tire more of a flat look, which makes the footprint larger and tricks the photocells into thinking it is much larger than it is. Likewise, more air makes the tire much stiffer, making the photocell think the tire is much smaller than it is.
Just like increasing and decreasing air pressure,changing tire size will change the tires rollout. This kind of change in tire height will completely affect a vehicles’ reaction time.
The least amount of weight and tread will contribute to less rolling resistance. A radial tire will further lessen this effect, thanks to the tires resistance to growth while making a run down the track.”-Tommy Kundrick
Another factor that plays a role in reaction time is the height of the tire itself. When it come to tires, drastically changing your vehicle’s tire size with drastically alter your reaction time. This principle of reaction time adjustment is based on the rollout of the tire itself. A 28-inch tall tire will have more rollout, resulting in a slower response time, and a 26-inch tall tire will give you quicker reaction times because a smaller circumference results in less rollout, but will lead to a slower elapsed time. In retrospect, a larger tire will result in a quicker elapsed time, due to the decreased rolling resistance and because it allows the car to gain more forward momentum than a smaller diameter tire before the tires leave the stage beams.
“The least amount of weight and tread will contribute to less rolling resistance. A radial tire will further lessen this effect, thanks to the tires’ resistance to growth while making a run down the track, unlike its bias-ply counterpart. A tire that is 6-inches wide will naturally have more rolling resistance than a comparable 4-inch wide tire,” Kundrik explains
The Sportsman S/R is a very capable street/strip tire that is available in a multitude of sizes that are compatible with 15 and 17-inch drag wheels.
The tire that has literally upheld Mickey Thompson’s name is the ET Fronts, one of the cornerstones of Mickey Thompson’s product lineup. Utilizing a bias-ply design and a nylon and rubber construction, much like there bias-ply ET Drag rear tires, this tire has superior resistance to chunking and a harder rubber compound that wears slower than rear slicks. The ultra-lightweight ET Fronts come in a wide range of sizes, from your standard Dragster 22/2.5/17 (PN 3004) to the new 27.5/4.0/17 (PN 30093), which is designed to in conjunction with a 17-inch wheel to optimize brake caliper clearance.
The ET Front is the go-to front tire for anyone who is looking to break records in a door car, dragsters, and land speed vehicles. It’s ultra-lightweight tubeless construction reduces rolling resistance and is capable of consistently performing under high-speed conditions.
These sets of pictures identify the different types of tread patterns that are currently available. The ET Front (left) has a low rolling resistance design for improved speed and control on a drag racing surface. The Sportsman (middle) blends track use with street-ability, thanks to its raised grooved thread pattern, while the Sportsman S/R is a full blow light-weight radial that performs with the best at the track.
A lot of late-model owners have begun slapping skinnies on the front and making their way to the dragstrip, and these new tires allow to choose between a DOT approved radial and a bys-ply 17-inch front runners”-Tom Kundrik
As late-model vehicles have made their presence more pronounced at the drag strip, it’s become apparent that factory 13-inch and larger brake setups found on these cars create a problem when attempting to strap on a set of bigs and littles. These 17-inch frontrunners now allow a weekend racer to get away from grinding calipers and using spacers in order to fit a set of 15-inch skinnies.
“We actually started this new 17-inch lineup in the Sportsman S/R version and it bled into the production of our ET Fronts. A lot of late-model owners have begun slapping skinnies on the front and making their way to the dragstrip, and these new tires allow them to choose between a DOT-approved radial and a bias-ply 17-inch front runners,” Kundrik explains.
Have a heavier track-going vehicle? The Sportsman bias-ply is the go-to for many racers that are looking for a lightweight front runner that carries a greater load rating without sacrificing the performance they need during competition.
The Sportsman series of bias-ply tires are designed for the racer who has a street/strip setup that will perform flawlessly at the track and get you home without having to change over to a different set of tires. Another reason for considering this type of tire is that the ET Fronts are not ideal for heavier drag racing vehicles, as they carry a C-load rating (a designation in reference to a tire’s load carrying capacity; in this case, ‘C” is usually designed for a light truck application). Other than carrying a DOT approved rating, these bias-ply tires employ a more aggressive tire pattern design, which helps manage the uncertainties that arise during a cruise to the track or to a local car show.
Check out the tread pattern on Mickey Thompson’s Sportsman S/R’s! These tire not only look cool but are completely functional on the street and the strip radial tires but they carry a DOT approved rating.
If street driving is more your style, with the occasional trip down the track, the Sportsman S/R radial is a viable option for anyone who wants to run a radial 4-inch frontrunner. The radial construction improves the ride quality and vastly improves tire life — perks that have led the Sportsman S/R to become commonplace in the hot rodding community. The tread construction has further contributed to this tires’ street-ability; the unique flame tread pattern provides better traction in wet conditions when you’re subjected to nature’s fury.
Both our True SStreet and Evil 8.5 project cars are utilizing the Sportsman S/R radials.
“Both the Sportsman and Sportsman S/R’s are put through their paces on an endurance test before gaining their DOT rating — the same testing that is subjected to our entire range of DOT-approved radials,” Kundrik informed us during our conversation. “This test requires the tire be to spun to 80 mph for 24 hours while loaded against a drum to simulate standard road conditions.”
Taking all this into account, the next time your land-locked missile needs a new set of front shoes, you’ll be better equipt to optimize tire performance, further opening the door to setting up a consistent starting line-killer by dialing in your reaction time with tire high and air pressure, giving you that edge you’re looking for … whether it be in a heads-up race in NHRA Pro Mod or at your local track bracket racing.