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The Truth About Torsion Bars

There are several options for developing a front suspension and one such design commonly found on light and medium duty trucks involves the enigmatic torsion bars.  The technology affords the comfort and control of an independent suspension while remaining robust enough for tough truck duties. Additionally, the geometry of a torsion bar system provides ample space for the various other drivetrain components like engines and four-wheel-drive bits.

But what do torsion bars do?

Drag and zoom the  diagram to see how torsion bars (magenta) sit in relation to the control arms (blue).

Although they accomplish very similar tasks, torsion bars function very differently than traditional coil or leaf springs. While a typical spring compresses vertically (up and down), a torsion bar provides its tension by a twisting action. One end of a torsion bar is rigidly attached to a frame cross member while the other is attached to a control arm pivot. As the control arm moves, the torsion bar’s resistance to twisting provides the springing effect.

I like big trucks and I cannot lie. Can torsion bars lift?

Our favorite feature of torsion bars is that they are super-simple to adjust for ride height. There’s even an adjustment screw, installed at the factory, near the end attached to the frame. The downside is that there isn’t that much adjustment available in stock guise and when the torsion bars are set to maximum height, the truck’s ride tends to turn horribly harsh. The upside, however, is that there are ample products available that afford up to 3” of lift from factory torsion bars without mucking up the ride quality.

This sounds complicated. Can I torsion bar at home?

The easiest way to safely lift your factory torsion bars is to upgrade the torsion keys. Torsion keys are machined steel plates that hang out on the frame ends of torsion bars and their job is to facilitate the adjustments in ride height. With a decent set of jack stands and a torsion bar unloading tool (readily available for purchase and easy to rent from major auto parts stores), the average handyperson can have a set installed in an hour or so. A professional shop may even be able to get it done in less time. Check out the video to the right where Supreme Suspensions’ fearless racing truck driver, Wade Wyman, demonstrates the installation of a set of torsion keys.

That seems fairly simple. Is there anything else I should know?

As with any other time you change the ride height of your vehicle, it’s always good practice to have an alignment performed when you’re done. The slightest change in suspension angles can have a big impact on the vehicle’s alignment and you’d hate to trash a set of tires that likely cost a fair bit more than the torsion keys that you’ve just installed.

1995-2011 Ford Ranger Front Suspension Lift Kit 4WD 4×4

  • 2x Front Lift Steel Torsion Keys
  • Installation instructions
PRODUCT ID# 11363
$89.95

1997-2003 Ford F-150 1″ to 3″ Adjustable Front Steel Torsion Keys Suspension Leveling Lift Kit 4WD 4×4

  • 2x Front Lift Steel Torsion Keys
  • Installation Instructions
PRODUCT ID# 13468
$84.95

2001-2010 Chevy Silverado / GMC Sierra 1500HD 2500HD 3500HD Front Suspension Lift Kit & Shock Extenders 4WD 4×4

  • 2x Front Lift Steel Torsion Keys
  • 2x Shock Extenders
  • Installation instructions
PRODUCT ID# 1537
$104.95

2011-2015 Chevy Silverado / GMC Sierra 2500HD 3500HD Front Suspension Lift Kit & Shock Extenders 4WD 4×4

  • 2x Front Lift Steel Torsion Keys
  • 2x Front Shock Extenders with Hardware
  • Installation Instructions
PRODUCT ID# 1071
$144.95

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