It’s no surprise that fads come and go in the automotive industry. The 1950s brought us moon disc wheel covers, chopped tops, frenched taillights, lake pipes, and more. Then in the ’60s, the enthusiasts were blessed with straight-axle gassers, killer wheels like American Racing’s Torq-Thrust, Radir’s Tri-Rib, Astro Supreme, and vibrant candy paint jobs. The ‘70s were full of more of the same with big-blocks, tunnel rams, and wild vans. And as technology changes, performance automotive companies keep pushing out new and improved components to meet modern needs.
One product that’s super-hot in the wheel market currently are beadlocks. We are seeing more and more of them on street cars, which brings up questions like “when do you need beadlock wheels?” and “what are their advantages?” Since we are currently building a full-size truck for the track, we thought this would be an opportune time to see if we need beadlocks or not. So, instead of listening to the internet, we decided to go straight to the source. Both RC Components and Mickey Thompson deal with high-horsepower race and street cars on a daily basis, and we knew they could answer any questions we might have.
What’s a Beadlock?
A beadlock is precisely as it sounds: a ring that bolts to the outside (and sometimes the inside with a double beadlock) of a wheel and is used to sandwich the tire’s bead between the ring and the wheel itself. This design locks the tire down and keeps the bead from rotating on the wheel when launching on a sticky surface. This is important not only to keep the bead from slipping but also to keep the bead seated. Centrifugal forces can separate the tire’s bead from the wheel at high speeds. If that were to happen, you could lose air from the tire, or in a worst-case scenario, it could come out of the seat and go flat immediately.
You might think that beadlocks originated from Top Fuel dragsters, but, that’s not the case. RJ Clutter from RC Components gave us some insight on this topic.
“Beadlocks originated in the off-road world for 4x4s due to airing down tires,” Clutter explained. “The first ones were on Dodge Military trucks called ‘combat wheels’ and were designed for quick and easy tire replacement during combat. However, the first beadlock wheel sold for off-road use was in 1980.”
As racecars started going fast throughout the years, racers looked for innovative ways to secure the tire to the wheels. They found some ways to keep slippage at a minimum, but their methods were quite archaic. For example, we’ve all seen guys drill out their wheels and then use screws to hold the bead. While this method has been used for years on bias-ply tires, it’s not recommended for radials. But, more on that in a minute.
Another way to secure a tire to the wheel is with glue. While this technique can be effective, there are no guidelines on how much or what type of glue to use that we’ve found for a racing application. Plus, who would want to deal with putting glue on a nice aluminum wheel?
When You Need Beadlocks
It seems like 99-percent of the fast guys on the track are running beadlock wheels. And since we are building a Silverado for the street class, we wanted to know if we would need beadlocks or standard wheels.
Clutter said, “It varies from one vehicle to another, but typically around 800 horsepower is when to start looking at a single beadlock. Then anything over 1200-1300 horsepower, a double beadlock should become standard.”
Since we plan to crank out 800-1,000 horsepower with the boosted truck, a single beadlock wheel is required. This brought up another question: are there any disadvantages to this locking design?
While some may be weight conscious with their racecars, we’re building a truck, and to us, and 99-percent of the fast racers out there, 12 additional pounds is a small price to pay to make sure the tire never rotates on the wheel. With that said and all of our questions answered, we ordered a set of RC Components Retro wheels in black with a polished barrel (also called “Eclipse Prism”). But, RC Components offers other finishes for this wheel, as well. Clutter said, “The Retro wheel is available in polished finish, Eclipse finish, Eclipse Prism, and chrome finish, and of course, is proudly made in the USA.”
We went with a 15×10-inch wheel on the rear in a custom offset, which is no problem for RC Components, for our Moser Muscle Pak rear axle we had narrowed and a 17×4.5-inch front wheel. -Caption
With the wheels on the way, it was time to turn our attention to the tires; for that, we turned to the experts at Mickey Thompson and spoke with the Motorsports Director, Jason Moulton.
Bias Ply Vs. Radials
Bias ply tires have been around for a long time and are the defacto choice for the majority of drag racers. However, radial tires, a relatively new technology compared to bias ply, are proving to be a more efficient design, with less rolling resistance. But our question was, which one is needed and under what circumstances?
“Generally speaking, we recommend using a bias ply tire when a racer utilizes a clutch and running a radial in an automatic.” Moulton continues, “Of course, there will always be a situation where a radial will work with a stick-shifted car, but that will depend on the power level and how you drive it. But for most applications, the bias ply tire is more forgiving on the driveline when you drop the clutch.”
At this point, we knew that a radial was the way to go with the tire selection for the truck because it’s an automatic — a TCI TH400, to be exact. And since it will see limited street duties, like cruises and to and from the track, the radial made even more sense.
“When you’re on the street, the drivability and handling of radial is the best choice,” Moulton confirmed. “When you put the radial on the track, the radial can always be quicker than the bias ply due to less rolling resistance.”
Radials And Beadlocks
Of course, by now, we already had a set of RC Components beadlock wheels on the way, but we wanted to get Mr. Moulton’s input on our tire and wheel combination while we had him on the line. So, we asked him about securing the tires to the wheels, which unraveled a significant bit of information. He said, “We tell people to mark the tire and wheel, and if the marks move a considerable amount [at once] or continually pass after pass, it’s time to get beadlocks. At that point, you’re getting enough traction out of the tire that something has to give.”
Don’t Get Screwed
As we mentioned before, radial tires don’t absorb as much power as a bias ply, making them quicker. A Top Fuel racecar, for instance, uses bias ply tires – you can see how much energy is absorbed as these monsters wad the tires up on launch in. the image below. A radial has a much stiffer sidewall that doesn’t flex like the bias ply. Ultimately, this is why it’s a horrible idea to use screws to hold a radial tire to the wheel.
“When you screw a bias ply tire to a wheel, the sidewall will absorb a lot of energy, so it’s not putting that much stress on the bead and trying to rotate it on the wheel,” Moulton explained. “On a radial, there’s so much energy at the bead that the screw can’t hold it. So as it rotates, the screw acts like a knife and cuts the plies right off the bead, which is catastrophic.”
While this series of unfortunate events sounds terrible, it’s much worse than you might think. This problem doesn’t usually occur during the launch at low speed but rather at high speed. Moulton said, “This failure typically transpires at the top end of the racetrack when the driver lets off the gas, which is the worst possible scenario. So we never, ever recommend rim screws.”
So if your buddy is thinking about rim screws and radials, be sure to talk him out of it. The company even has a technical bulletin on this subject if you need more help to persuade them toward a beadlock wheel.
Mickey Thompson ET Street R
The radial selection for our truck was a simple one — we needed a high-performance radial that is D.O.T. legal, which led us to Mickey Thompson’s ET Street R for the rear. “The ET Street R is a race tire that you can drive on the street, obviously under dry conditions only,” Moulton explained. “This tire uses the same technology and compound used in our ET Street Radial Pros. So the ET Street R is a race-bred tire that is a competent street tire, as well.”
ET Street R Specs:
- D.O.T. approved for street use
- Minimal tread void provides excellent tread contact
- Available in most popular sizes
- Tubeless construction provides a leak-free seal without the expense and hassle of tubes
Initially, we opted for 15-inch wheels on the truck’s rear and 17-inch for the front because we like the look. However, there are some performance advantages to doing a 15-inch tire and wheel combination on the back for added consistency at the track. Moulton said, “by adding section height (a taller sidewall) to the rear tires, you’re allowing the sidewall to absorb more energy, even though it’s a radial. But, it also depends on the horsepower level. If you have a 14-second car, you’re not going to see a difference. But, if you have an 8-second vehicle, there’s definitely a chance you can see the difference between the two tires.”
Mount And Balance
After a couple of weeks, we had our custom-offset RC Components wheels in hand and a set of Mickey Thompson tires. For the rear, we went with a 275/60/15 ET Street Rs and up front, we chose Sportsman S/R tires in 28/6.00R/17. We loaded the new combination up and headed to our good friends over at 4 Wheel Performance for mounting and balancing. Jeremy Nichols mated the pairs together for us before balancing them. The most cumbersome part of the process was torquing the beadlocks down on the rear wheels. It isn’t a big deal, it just takes some time to get all of the bolts torqued.
With the tires and wheels back home, it was time to utilize the five-lug swap that we had just done a few weeks earlier. So we mounted the tires and wheels on the Silverado and torqued the RC Components lug nuts before setting the truck back on the ground. And I have to admit, I will go out of my way to walk by the Silverado with its new package, which in my honest opinion, looks killer. Now, if we can just finish this truck and get to the track, that would be fantastic!