The Mod You Didn’t Know You Need!

In the car world there are 4 go to mods that every car guy (or girl) goes to off the bat.

  • Lowering springs
  • Wheels
  • Intake
  • Exhaust

These are the core essentials, whether you are building a 200mph drag car, or your first car. Before I get some flack for this, yes – you might get coil overs or some other cheap/ghetto form of lowering your car like cutting coils, but the point is this: you are lowering the car.

Lowering your car isn’t as simple as just swapping some springs, or bolting in a coilover kit. Auto manufacturers spend literal millions on engineering the suspension geometry to be safe, and react like it should to bumps, braking, and steering input. When you buy a aftermarket set of lowering springs or coilovers you upset this geometry.

Even if the coilovers are at stock height, the cycle of motion in the aftermarket spring may be different and cause a single parameter of the suspension or steering to be out of the allowable working range.

In other words, just putting springs on your car can take your $40,000 sports car and make it drive and feel like a $400 clunker. Don’t worry… there is a solution!

This solution is a Bumpsteer Kit.
To picture what it does, first know that there are many kinds of suspension, I know most my readers are Mustang enthusiasts so I will focus mostly on 1979-2018 Mustang style suspension known as MacPherson Strut. When your car left the factory, the lower control arm and the steering arm (tie rod) had parallel movement, meaning that there was never a bind or a arch of motion different from each other. In this case there would be no need for a Bumpsteer kit, since everything is in a good working range of motion.

However, when you lower your car, you upset this parallel movement The control arm and steering arm no longer move in unison. How low you take your car from the stock height will determine how severe and when you feel the bumpsteer. You will feel the bumpsteer when you upset the steering, be it a bump, dip, or uneven surface on the road.

Here are some examples of extreme lowered cars, these pictures show very where the relationship of angle between the lower control arm and the tie rod. If either of these cars did not have the bumpsteer kit it is very obvious how much of a bind and toe bind the steering would be in.
Note: both these cars use 94/95 spindles and would benefit from a 96+ style spindle
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In both the examples above the bumpsteer kit uses shims, as most the kits on the market do. This is a very time consuming task as each time you take or add a shim to the stud then measure the needed “bump” with a bumpsteer gauge. However, there is a new product on the market, a “shimless” bumpsteer kit that allows you to keep the stud bolted to the spindle and simply turn a threaded body as needed. This makes the time needed to dial in a bumpsteer kit significantly less and a lot less headache.
sn95-shimless-bumpsteer

If you think that dialing in your bumpsteer kit might be over whelming don’t worry, there are a few solutions. First would be just getting your angle close, this is typically perfect for street use and a HUGE improvement over not having a setup at all. Second, would be contacting a local track shop, in our immediate market we suggest Chicane23 (chicane23.com), they can typically have the kit installed in a day or 2. Lastly, buying a bumpsteer gauge yourself and dialing it in.  To set the bumpsteer on a conventional spring setup, the spring has to come out, reinstall the strut, set the bumpsteer, and then reinstall the spring with strut. This process has to be done to allow the control arm and tie rod to fully articulate.

Here is a visual example of what bumpsteer is.

While the above video is describing the rear suspension of the concept applies to front suspension as well.

Please feel free to contact us at Sales@dashengst.com for recommendations for your bumpsteer kit.
http://www.dashengst.com/bumpsteer

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