Street Rod Torsion Bar - Suspension Alternatives - Rod and Custom Magazine

So, Where Are The Springs? Torsion Bars for Street Rods

Harry Nicks was a man on a mission. At the wheel of his immaculate ’29 roadster, he was looking carefully for broken pavement, railroad tracks, potholes, and other irregularities in the asphalt.

He didn’t want to miss them, though. While most rodders would drive city blocks out of their way to avoid such hazards, Harry wanted to hit them—at speed. And there we were, riding shotgun, wondering how many fillings we were going to knock loose when Harry found his dream pothole.

But that didn’t happen. Oh, we hit the hole all right. The roadster dipped, rebounded, and settled. No loose fillings, no jarred kidneys, no muss, no fuss. A new Corvette would have bounced harder in that hole than Harry’s roadster. You see, Harry’s ’29 is different than most. Look closely under its track nose and you won’t see buggy springs along the dropped axle. You won’t see any springs, in fact. Shocks, sure, but no springs. They’re tucked neatly away in the frame.

Harry’s roadster is fitted with front and rear torsion bars. The front bars are housed within the boxed framerails, and the rears run parallel to the split links that locate the axle. It’s a tidy installation, but more than that, it gives Harry’s fenderless ’29 something few old roadsters have: a new-car ride.

Harry runs Nicks Old Car Specialty, a full-service shop in Southern California that builds and restores hot rods, musclecars, and old sports cars. As Harry put it, “We do everything here: body and paint, engine building, chassis building, everything except chrome and upholstery.” Now that includes fabricating custom frames with torsion bars for “just about anything from a ’27 to a ’34,” says George Eckardt, who works with Harry and who engineered the suspension system. At this point, the “just about” qualifier means the system is designed to work with solid axles; R&D on independent suspensions will come later. “But we can accommodate any rear axle,” George tells us, “from a 9-inch to a quickchange, and even a Pro Street axle.” Also on the drawing boards—or at least in George’s mind—are torsion-bar systems for ’40 Fords and other full-bodied street rods.

The genesis of the system came from George, who wanted to build a ’33 with an Indy-type suspension and torsion bars in the frame. However, the first real application was on Harry’s ’29. Remarkably, George didn’t draft the system on some powerful CAD-CAM computer. He did it the old-fashioned way, with a pencil, calculator, and paper.

The torsion bars aren’t salvage-yard specials; they’re brand-new tubular (not solid) bars custom-made to George’s length, diameter, and rate specifications. They sit inside a tube, ride on moly-filled nylon bushings, and attach to the axles through lever arms and adjustable links.

When we asked George how he determined spring rates for a given application, we could tell he didn’t want to reveal too many trade secrets. “There are formulas, lots of formulas,” he began, and then smiled and stopped talking. The bottom line is this: If you provide George with some basic information about what kind of car you’re building and its intended engine and driveline, he can pretty much figure out how much weight will be sitting on each axle and plan the spring rates from there.

Actually, most of the planning goes into the length of the lever arms, not the dimensions of the torsion bars. Since the cars currently under construction are so similar in terms of weight, George has been able to order a batch of bars with the same rate. He then tailors that rate to the specific car by varying the length of the arms.

Since the arm applies leverage from the axle link to the bar, shortening the arm reduces its leverage and therefore increases the spring rate. It doesn’t take much of a change in arm length to make a big difference in rate. George told us that changing the length of the lever arm by as little as ¼ or ½ inch can alter the effective spring rate by 25 pounds or more. Further ride tuning can be done via the 12 settings on the HAL QA1 shocks that you can order with your chassis.

Note the “order with your chassis” phrase. The Nicks torsion-bar system cannot be easily retrofitted onto a chassis originally designed for conventional springs. “It can be done, but there’d be so much work involved that you’d be better off starting from scratch,” George told us. “Everything in the system is custom-built and built to fit. Nothing is adapted from somewhere else.

Everything is designed to work with everything else.” So with all the time and effort, not to mention expense, that you’d need to make this system fit another chassis, you might as well start fresh.

Besides, Harry won’t sell just the torsion bars. He doesn’t want someone to try and cobble together a system just to wind up dissatisfied. He’d rather do it right the first time and keep his customers happy. “You call us, tell us what you want, and we’ll build it.”

That’s how Harry wants to run the torsion-bar portion of his business. He doesn’t envision an inventory of frames stacked in a storage room. He’ll build them one at a time to order. There are currently three torsion-bar chassis under construction in Harry’s shop, two for ’32s and one for a ’27 T that’s going on ’32 rails.

Since Harry’s is a full-service shop, you can order your chassis in just about any stage of completion. His standard chassis will include the suspension, dropped front and 9-inch rear axles, disc brakes at all four corners, master cylinder, brake pedal, and all brake lines plumbed. If you want the gas tank installed and plumbed, they’ll do that. “Hell, we’ll build the entire car if they want,” said Harry.

Since these chassis are custom jobs, they’re not inexpensive. The standard roller we just described will sell for around $21,500. That’s serious money no matter how you look at it. But if you have any doubts about justifying the cost or any worries about how well the system works, go visit Harry. Let him take you for a ride on the busted-up streets around his shop. You’ll come back a believer.