Factory Front Sway Bar Diameter

[Racket]

@P. A. Schilke ?

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[P. A. Schilke]

@P. A. Schilke ?

Hi John,

Al is correct that increasing roll stiffness at the front will promote more understeer. By design and tuning, the truck understeers as almost drivers are more comfortable with understeer and more unsettled with oversteer. Some folks use the term Push and Loose. (read NASCAR...). So making the front bar more effective due to the aftermarket bushings will change the roll stiffness balance and introduce more understeer. If this is your desire, then you are on the right track. If in fact you want to tighten up the car you might need to add a rear bar to keep the roll stiffness balance front to rear close to what you currently have.

Put another way, The tires have the greatest slip angle on the stiffest end of the truck, currently the front of the truck. That is why I question just installing a Helwig bar without an associated adjustment tweek at the front to maintain balance. I ask the question...do you expect to loosen up the truck? If so...add the Helwig bar.

Make sense?

best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[Racket]

Hi John,

Al is correct that increasing roll stiffness at the front will promote more understeer. By design and tuning, the truck understeers as almost drivers are more comfortable with understeer and more unsettled with oversteer. Some folks use the term Push and Loose. (read NASCAR...). So making the front bar more effective due to the aftermarket bushings will change the roll stiffness balance and introduce more understeer. If this is your desire, then you are on the right track. If in fact you want to tighten up the car you might need to add a rear bar to keep the roll stiffness balance front to rear close to what you currently have.

Put another way, The tires have the greatest slip angle on the stiffest end of the truck, currently the front of the truck. That is why I question just installing a Helwig bar without an associated adjustment tweek at the front to maintain balance. I ask the question...do you expect to loosen up the truck? If so...add the Helwig bar.

Make sense?

best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

Thanks Phil. You've done a nice job of validating all if us in this thread I think (?).

IIRC Helwig recommended the rear sway bar for trucks primarily used for towing.

I don't see stiffening the front a degree - I'm not considering a larger bar - would be a step towards considering a rear bar, but I don't tow exclusively. I've raised my front suspension one and a half inches to sort off level the appearance which I presume has pre-loaded the suspension. I'm less satisfied about how the front end pitches into turns. I feel one front corner is being asked to carry a lot more traction than I am comfortable with.

Already considering new tires since that's usually a go-to for handling.

....still no replacement bushings in urethane out there.

 

[Racket]

I've since changed my rear springs to the softer UK multi-leafs to go with the Eibachs and added Sumo progressive bump stops. It's changed the rear behavior and I'm still looking to bring the front up in initial turn in. The small change the front Eibachs provided changed things already that I'dliketo 'correct.' In another thread Addco has introduced a big front bar that would reasonably require a rear bar and Hellwig is the only option. For a 'street' truck It's some serious coin and would take a lot of adjustment. Addco says our stock bar is 27.5mm so a generic bushing is going to be near impossible to find.

In lieu of the Hellwig rear bar the Roadmaster rear active suspension would be a thought, although I'm not a huge fan of the extra complexity.

When swaybars reach the end of their performance limits lateral traction becomes an 'issue' that a truck - depending on how it's being utilized can have catastrophic results.

 

[Racket]

With my handy dandy new electronical caliper I can confirm the front factory sway bar is indeed 27mm in diameter at the frame bushing and 100mm bolt to bolt for the bracket. As of yet I haven't found any quality replacements. An option I might pursue would be getting smaller diameter bushings and have a machine shop open them up?

 

[RedDakooter05]

With my handy dandy new electronical caliper I can confirm the front factory sway bar is indeed 27mm in diameter at the frame bushing and 100mm bolt to bolt for the bracket. As of yet I haven't found any quality replacements. An option I might pursue would be getting smaller diameter bushings and have a machine shop open them up?

That's what I'd do, although do the task myself.

Some sandpaper and patience you can bore a bushing nicely. Or just pay to have a shop bore it I guess.

Im poor so I tend to do things myself when I can.

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