The search for a smooth ride...
The search for a smooth ride led Russ Young and his roadster pickup from Bonneville back to his NorCal home and Dave Davidson's Vintage Hot Rod Design and Fabrication, a stone's throw away. Along with state-of-the-art equipment, Davidson also has vintage Amermac tire truing machines. Young has that big grin on his face thanks to the T's new demeanor.
It's said that hindsight is 20/20, but when it comes to the way street rodders view nostalgia we're often a little more shortsighted than that. Take the use of bias-ply tires as an example. They look cool, and on some cars there's just no other choice to make it right, but on the other hand there's a reason the rest of the automotive world rolls on radials. Just about every street rodder knows that radials ride and handle better, last longer, and so on, but we're willing to forget all that. However, there is one common complaint that most of us would do something about if we could and that's the vibration that can't be cured by balancing. In a nutshell the reason for this is that bias-ply tires are sometimes, well, the shape of a nutshell-they're not always perfectly round.
Russ Young has a perfect example of a hot rod that has to wear bias-ply tires; his Flathead-powered T just wouldn't be right with any other rubber. Unfortunately, the rubber it was equipped with were perfect examples of tires that would never be right. Balancing alone wouldn't get rid of a persistent vibration, but Young found the cure. During a discussion with a veteran hot rodder at Bonneville about all things vintage, Young was asked if he had shaved the tires on his roadster and was told that was the secret to a smooth ride. The problem was finding someone with the equipment to do it. Ironically, Young found that there were two Bonneville veterans practically in his backyard who had what he was looking for.
While some shops have a tire-truing...
While some shops have a tire-truing machine, this is the more rare tire warmer. It works out flat spots in the tire that result from setting and warms the rubber to soften it. As Young found, enough pressure is applied to the tire by the top roller to cause significant deflection of the tread.
This is an Amermac tire-truing...
This is an Amermac tire-truing machine. The wheel and tire is spun while the control handle on the left swings the cutter from side to side, the control on the right feeds the cutter into the tire, and the small control below it raises the drive for the tire. Note all the wheel adapters hanging below; they are double sided so each serves two bolt patterns.
Switches on the truing machine's...
Switches on the truing machine's control panel control the cutter's direction, the rotation of the tire, and a work lamp.
Here's the business end of...
Here's the business end of the machine: the cutter. Below the blade is the sharpening stone; it's used as necessary during the cutting operation.
Dave Davidson and John Beck have been racing together and setting records at the Salt Flats and dry lakes for over 20 years. Davidson is the proprietor of Vintage Hot Rod Design and Fabrication in Chico, California, a 15,000 square foot facility that does everything from maintenance and repairs to ground up, turnkey cars. Beck works out of the same facility and is one of the premier engine builders in the country who can provide anything from a restored Flathead to a trophy-winning sprint car engine. To top it off, these guys have what it takes to true bias-ply tires.
The equipment required to true out-of-round tires consists of two machines made by Amermac-one warms the tire, the other trims off the high spots and contours the tread. Once commonly found in tire shops, as bias-ply tires became far less common, the demand for tire truing and the equipment that did it faded away. As a result, many of these machines were just taking up valuable shop space and were sold for scrap. Fortunately, thanks to extremely robust construction, those machines that did survive are still capable of doing what they were designed to do. Davidson and Beck had been truing Bonneville tires for years with vintage Amermac machines, and with the growing popularity of bias-ply tires on street rods, it's a service they now offer to customers.
A mounting fixture with the...
A mounting fixture with the appropriate bolt pattern secures the wheel and tire assembly to the machine. Normally the fixture fits the lug nut side of the wheel, but for these wires Davidson had to make a special mount that sandwiched the mounting surface from both sides.
Once the wheel and tire is...
Once the wheel and tire is mounted in, the machine numbered templates are used to determine the shape of the tread. Before truing, tires were inflated to 30 psi.
A pair of adjustable bars...
A pair of adjustable bars is clamped into position based on the number on the previously used template. The cutter is then brought up to the tire tread by the feed control.
In this case, the sliding...
In this case, the sliding bars that position the tire were set on the number eight, corresponding with the number on the template.
Truing bias-ply tires can make an amazing difference in ride quality, and the amount of rubber removed has very little impact on tread life. However, there is one caveat, the procedure is usually reserved for new tires. The presence of any foreign objects in the tread can damage the cutter, so used tires aren't normally candidates for the process. How do you know if it needs to be done to new tires? Simple enough, spin 'em and see how round they are. If they're not true you now know the cure for out-of-round rollers.
Amermac
A Brief History and a New Beginning
Lillian Flynt was an Amermac employee for 39 years. As she explains it, in 1959,Roy Peacock Sr. owned a tire shop in Americus, Georgia, and saw a need for tire truing. He developed tire-shaving equipment, which he had manufactured by Greenfield Metal Products (GMP), also of Americus. Peacock formed Americus Manufacturing (later Amermac) to provide development, marketing, and support for this equipment. As it grew, GMP moved about 12 miles to Ellaville. In 1979, GMP purchased Amermac. By then the "vibration correction equipment" was used by the trucking industry and had found its way into auto racing.
This is the tire warmer in...
This is the tire warmer in action. An electric motor spins a roller that turns the tire; the pressure roller is controlled by air pressure. Note the guides on the sidewalls that keep the wheel and tire centered on the rollers.
The heat sensing gun shows...
The heat sensing gun shows the tire tread is up to 125 degrees.
Here, the crown in the tread...
Here, the crown in the tread of a 5.50-15 bias-ply tire can be seen.
As Davidson looks on, John...
As Davidson looks on, John Beck carefully feeds the cutter into the tire.
With the introduction of radial ply tires the need for truing declined and the equipment began to disappear from tire shops. GMP also manufactured metal closet shelving. With the severe decline in the housing market, GMP was forced to close its doors.
Wes Sprunk, the owner and president of TSISSG Tire Service Equipment (www.tsissg.com) had followed Amermac for years but had not been able to add it to his successful tire service equipment company. Finally, in October 2009, he was able to acquire the physical and intellectual assets of Amermac and is now making tire-truing equipment available once again.
Beck trues one tire while...
Beck trues one tire while another spins in the warmer.
As the cutter is fed into...
As the cutter is fed into the tire, it swings side to side on an arc established by the adjustable and numbered locating arms.
After truing the wheel and...
After truing the wheel and tire assembly, balancing is next. For the utmost in precision, Davidson built a trued-and-balanced hub to mount early Ford brake drum, wheel, and tire assemblies on his tire balancer.
There's rubber inside the...
There's rubber inside the machine that will never meet the road. The worst tire off the T was almost 3/16 inch out of round.
In cases where lots of rubber...
In cases where lots of rubber is removed from the tread it may take a considerable amount of weight to balance it.
Andrew Givens at the Honest...
Andrew Givens at the Honest Charley Garage provided a photo of their machine that shaves the tire on the vehicle. It's then placed on a balancer for fine tuning. He also mentioned the importance of indexing the wheel, so that it goes back on the vehicle the same way it came off.
Vintage Hot Rod Design and...
Vintage Hot Rod Design and Fabrication can handle any phase of car construction and has a retail area where you can find everything you need to build your own, including cool Hawaiian shirts to wear when its done.