Quote:
Originally Posted by M249cummins
(Post 2663382)
why is it you don't see too many people run traction bars on the front? I have a 6in lift and got some pretty decent wrap and wondered why you never see bars on the front axle, why is that?
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A little late for this one, but I think I have an answer. It's a bit unrelated but certainly dovetails into your question. When cars were first made back in the early 20th century. The original suspension systems were designed to articulate as the existing roads at the time were usually unpaved and usually in bad shape. The Model T featured large diameter tires, high ground clearance and traverse leaf springs. You can find old photos of Model T's with their axles all crossed up. But as paved roads spread across the country and cars could drive faster, those early suspension systems were inadequate, and the suspensions began to evolve for the higher road speeds. The traverse leaf spring was replaced by a pair of longitudinal leaf springs which was a huge improvement.
Longitudinal leaf springs have a few quirks that designers had to adapt to. To get a soft or smooth ride, you needed to use longer leaf springs. However when a leaf spring deflects, the length of the spring changes slightly. As the suspension travels up and down, half of the spring pivots from the fixed hanger end, while the other half of the spring moves fore and aft slightly. As a result, the axle also happens to move fore and aft a little too. It's acceptable to allow the rear axle to have a slight fore and aft motion when the suspension flexes, but the front axle controls steering and if one side of the axle articulates, it creates a slight tiller effect and the entire axle pivots and makes steering a lot more vague. At highway speeds this is unacceptable. So what the manufacturers did was to limit the front suspension, and they usually went with much shorter leaf springs in the front, which helped shorten the fore and aft movement of the axle during suspension movement and suspension travel was limited to a fraction of the rear. Then cars began to receive IFS
This short front leaf spring design concept was carried on to trucks and continued decades later. So if you happen to look at a typical leaf spring equipped pick up, you'll see that the front springs are shorter than the rear springs and the suspension travel was also much less than the rear. There probably wasn't ever a problem with the need for a front traction bar because short leaf springs take more effort to wrap up, or maybe engines were lower powered but fast forward to today and a lot has changed. Trucks are more powerful than ever before, tire size grew, gears ratios are deeper, suspensions are lifted, and now we have the need for a front traction bar. But then again, leaf springs aren't being used as much anymore either.
Theres no reason that you can't install a traction bar on the front axle. The same physics apply for a front leaf sprung axle as it does for a rear.
You can do a 4 link, or ladder bar if you want, but keep in mind that axles have to articulate so any traction bar you add, must not prevent the suspension from flexing. This will add complexity to your design, but it is doable and it has been done.
Ed
