Q&A: Talking 7075 Alloy Driveshafts With Mark Williams

By Lindsey Fisher of Dragzine.com
Posted on Aug 2, 2013 in Drivetrain on Dragzine.com


The right driveshaft can mean success on the track as much as it can mean disaster. That’s why it’s so important to weigh the options when it comes to choosing a performance driveshaft for your performance vehicle.

A leading name in the industry since 1964, Mark Williams knows this well and has dedicated decades to becoming one of the most self-sufficient automotive design, manufacturing and testing companies in the racing industry. Specializing in racing and industrial driveshafts, and other driveline related products, the latest in driveline technology is exactly what MW aims to give to their customers. So we recently reached out to them to give us the scoop on their technologically advanced 7075 Aluminum Alloy driveshafts.
The 7075 Alloy Driveshaft
Among the driveshafts in the Mark Williams 7075 Alloy lineup is a direct replacement shaft for the GT500 Ford Mustang. The only slip-style shaft that Mark Williams produces, this replaces the stock two-piece driveshaft in the Shelby and offers a stronger and lighter choice for the high torque and 150+ mph speeds the production car is capable of.

Available in two different sizes (3.5-inch x .125-inch for 1350 U-joints, and 4-inch x .100-inch for 1480 U-joints), the 7075 alloy driveshaft exceeds SFI 43.1 specifications and is custom built for your application’s length requirements. The 7075 alloy driveshafts also feature 7075-T6 end yokes, exclusive Hi-Impact 1350 or billet 1480 series U-joints, and universal bolts for easy installation.

Adding to the component’s strength, the 7075 driveshaft goes through a patented Accu-bond process during manufacturing, which Williams’ states, far exceeds the strength of weld bonding for added performance and strength of the overall component. This means no weak spots where heat from a weld has compromised the strength of the aluminum.

At just 13.7 pounds, we’re talking about a serious weight-to strength advantage for the 7075 alloy driveshafts. This means less rotating and static weight in your car, less power that’s needed to spin the driveshaft, and more power that can be put to use breaking records on the track.

We sat down with the man whose name the company bears, Mark Williams, to learn more about the 7075 driveshafts and the benefits that they offer.

DragZine: What makes the 7075 Alloy driveshafts different than the other driveshafts that you offer?

Mark Williams: “7075 aluminum material strength is approximately double the strength of a 6061 aluminum shaft. Because 7075 is not weldable by conventional means, our shafts are manufactured using a patented bonding process. The thinner wall allows a lighter shaft and higher maximum operating RPM than conventional aluminum and steel parts. The additional strength from the bonding process allows us to build a shaft that will withstand the abuse of Pro Modified drag cars, featuring our 1480 series universal joint transmission and differential yokes.”

DZ: What applications would benefit most from installing a 7075 Alloy driveshaft?

MW: "Any application, street, strip or oval track, where rotating mass and strength are a concern, will benefit from using this shaft. The Pro Stock and Competition Eliminator classes currently use this shaft the most.”

DZ: You offer three different driveshafts with 7075 Alloy end yokes but just one driveshaft made completely of 7075 aluminum.

Can you explain the differences between these three driveshafts and how each of them would be beneficial to vehicle owners?

MW: “The three shafts that use the bonding process have either 7075, 6061, or carbon fiber tubes. 7075 tubes allow us to make a lighter and stronger driveshaft than the 6061 tube. This is the preferred driveshaft where cost is not an issue.”

“Carbon fiber is used in applications where length is an issue, and power is less. Cost is also a deciding factor with carbon fiber. There is a real advantage to having a bonded driveshaft as opposed to a welded shaft in terms of strength. A welded shaft will always have a weak spot surrounding the weld where the heat from welding affects the heat treat of the aluminum."

DZ: Do you offer 7075 Alloy driveshafts for all racing applications or just specific vehicles?

MW: “Just about any application that uses a 1350 or 1480 series joint can utilize the 7075 shaft. The main application limitations are maximum operating angles of the universal joints.”

DZ: How should a competitive racer go about choosing the best driveshaft for their specific application?

MW: “The choice of shafts has two design factors that are inter-related. They are the shaft length and the maximum RPM the shaft will see. A longer shaft requires a larger diameter tube size. The lighter the material and increased stiffness increases the RPM (critical speed) the shaft can operate at. The critical speed limitation is when the RPM and the natural frequency of the shaft coincide. The harmonics multiply and create an unstable rotating mass, resulting in a jump rope-like effect on the driveshaft. Too much time at the critical speed will result in the driveshaft destroying itself.”

DZ: What else should people know about your products, specifically your 7075 Alloy driveshaft options?

The 3-1/2-inch diameter Accu-Bond 7075 aluminum driveshaft with an exclusive 7075 Aluminum tube, 7075-T6 end yokes, 1350 series U-Joints. This shaft features exclusive Hi-Impact 1350 series U-Joints.

MW:
“All the 7075 aluminum shafts exceed the SFI 43.1 specifications by a wide margin. We manufacture a new model of 7075 driveshaft with an internal slip joint that replaces the trouble prone two-piece Mustang driveshaft. Currently these shafts are being used in the Shelby GT500 and GT1000 cars.”

“These have proven to be the only product that will withstand the abuse of these factory hot rods. Driveshaft safety should be a great concern. Investing in a quality product just makes good sense from a safety perspective as well as a performance perspective.”

Driveshafts like these from Mark Williams define modern manufacturing and technology, with a design and material structure that creates the best of both world’s for drag racers with lightweight characteristics that don’t sacrifice the much-needed strength and durability that’s just important to racers as weight. If you’re in the market for a driveshaft upgrade, we hope that this information will help guide you toward the purchase that best fits the needs of your application.

   
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