The Delta-1 drag racing drive wheel, named for the change it will bring to drag racing, started as an idea for the ultimate Pro-Stock wheel in the mind of Scott Rider, Weld Racing’s V.P. of Engineering, in 2003. He conceived a wheel whose construction was materially skeletal. It would be the purest, simplest shape to connect the tire to the axle by placing metal only in the direct load paths on the drive wheel of a drag racing car and removing metal everywhere else. He sketched the basic shape of the ultimate drag wheel and moved on to other projects.
Scott’s involvement in drag racing competition as a driver and an engineer continued to give him insight into the racers’ wheel needs. He guided Weld Racing’s advancing Bead-Loc technology and served as a member of the Medlin Project group, an investigation into Nitro Car wheel and tire dynamics by John Force Racing, Goodyear, and Weld Racing.
When Weld Racing changed hands and became Weld Racing LLC in November of 2008, Scott saw the opportunity to bring the Delta-1 concept to reality. By then Scott realized that there needed to be multiple versions of the Delta-1 concept for various classes and that a Nitro version should be the top priority. Nitro cars put the most stress on wheels with the tremendous torque from their 8,000 horsepower engines, high centripetal loads from 300+ speeds, and radial loads from aerodynamic downforce. From the initial design for the SFI 15.4 wheel, the SFI 15.3 and 15.1 wheels could be designed to be lighter due to lower torque application, static loads, aerodynamic loads, and lower terminal speeds. A staggering number of hours spent in Computer Aided Design software and testing in Finite Element Analysis over 3 years by the engineering team resulted in a spartan design with a unique cross section for each application. The 1-Piece forged construction and 100% CNC machined shape offers optimum control of the wheel cross section for superb stress distribution, strength, and longevity.
The graph below illustrates the stiffness and strength of the Delta-1 vs. contemporary wheel construction. The detail of note is the linearity and low slope of the Delta-1 load vs. deflection graph line in red compared the other wheel in blue. The upward curve toward vertical of the blue curve indicates the wheel has reached its elastic limits and is now deforming. The flat red line of the Delta-1 indicates it is far from its elastic limits and has a deep reserve of strength. The amazing fact is that it is substantially lighter than the wheel beginning to fail in the graph!
Scott’s long experience with Bead-Loc development also contributed to the Delta-1. The very stiff, yet light, Bead-Loc rings are held in place with studs to ease installation and improve durability during tire changes. The Delta-1 wheels have a Bead-Loc™ bolt circle pattern that is very close to the tire bead. This improves the leverage of the Bead-Loc ring on the bead seat and makes the clamping force on the tire uniform throughout the tire bead seat improving bead retention and safety. To eliminate point-loading of the fasteners, the rings have hemispherical seats that mate with hemispherical titanium washers under the 12 -point stud nuts. When the Bead-Loc is torqued down it only contacts the tire and the hemispherical washers. It does not “toe-clamp” the tire by contacting the rim shell. This prevents a v-shaped bead channel that would force the tire bead out of the Bead-Loc ring at high speeds and loads. The result is a wheel and tire system integration with superior tire sidewall phase management and control.
The Delta-1 forged one piece drive wheel is the new bench mark for drag racing drive wheels. In its SFI 15.1, 15.3, and 15.4 versions it is the lightest, stiffest, and lowest rotational inertia 16” x 16” double Bead-Loc™ wheel built anywhere, yet it does not sacrifice safety for speed.
It is not often that a single bolt-on product will improve every performance aspect of your race car, from reaction time, to elapsed time, to top speed, to safety.
Additional features and benefits are:
Twice as stiff resisting bending load from axle than competitive wheels to drive straight down the track
Tire bead seats are 50% stronger to stay more round under extreme loading
True to less than 0.005” total indicated runout at the tire bead seat for vibration free speed
Rotational moment of inertia is 9.82 lb*ft^2, versus 18.47 lb*ft^2 for competitive SFI 15.4 wheels, a 47% reduction to improve acceleration
TF1 SFI 15.4 – weighs 29.3 lbs, TA1 SFI 15.3 – weighs 24.5 lbs, PM1 SFI 15.3 – weighs 23.0 lbs, PS1 SFI 15.1 – weighs 18.9 lbs
The Bead-Locs are retained by (18) 5/16” studs on the SFI 15.3 wheels and by (24) 3/8” studs on the SFI 15.4 TF1 wheel for ease of maintenance and secure tire clamping
The PS1 SFI 15.1 wheel utilizes a unique Ultra-Drive hub with segmented drive flanges for additional static weight reduction
Many features of the Delta-1 series are patent pending
The Delta-1 wheel line has four current members, all in 16” x 16”. The PS1 is designed for Pro Stock and other SFI 15.1 applications such as Super Gas and Top Dragster. The PM1 is designed for brutal Pro Mod cars with an SFI 15.3 recommendation. The TA1 bridges the gap between the PM1 SFI 15.3 Pro Mod wheel and the TF1 SFI 15.4 Top Fuel wheel for Top Alcohol Dragsters and Funny Cars that need more strength than a Pro Mod car, but not as much as a Fuel car. By designing wheels for specific needs, weight, the enemy of all racing cars is minimized while maintaining a high safety factor.
As in 2001 when Weld Racing introduced the one-piece forged front wheels for drag racing, a product revolution has begun from the home of innovation and applied technology. Weld Racing, made in the U.S.A.
For more information, visit www.weldracing.com
This story was originally published on July 2, 2012. 
