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Classicswede 27/27mm sway bars

A hollow bar does not lose much stiffness. D^4, yadda.
I would not put more than a 19 on the rear unless I was road racing, and it was a last resort.
On the front I prefer a 23 over a 25.
 
That too. All these rear bars are way too big. I like 25/19 on my 940 although it's still too much rear bar. I think we run 23/16 on the race 245. Whatever the biggest factory front and smallest factory rear are. The 900 gets more sway bar because it's a big couch of a machine.
 
With more rear sway bar you lose what little traction you have on corner exit due to lack of rear suspension articulation. This is an especially big deal with an open diff.
 
Good reading on hollow sway bars: http://terminator-cobra.com/Sway%20Bar%20Tech.pdf

sway-bar-formula-840x.jpg


Did some math using these and the dimensions I had on hand (940 front sway bar, just an example)

27 mm bar with 0.188" wall thickness (wall thickness admittedly pulled out of my butt/stolen from Hotchkis in that PDF):

482.56 lb/in torsional stiffness (please note this isn't at the wheel, motion ratio from wheel to end link applies)

25 mm solid bar:

430.63 lb/in torsional stiffness

OD^4 trumps all, indeed.
 
interesting, thanks.

ipd sells the front and rears together, with
25-25
or
25-22
combos.

for a good compromise on a fun street car, stock height,
25mm front and the 19mm I have from a 79GT vs 25mm front and nothing?
 
Would a stiff rear sway bar be good for drifting?

only if you want to be the slowest car at the drift event with unpredictable behavior.

Initially a welded diff with a big bar and 60psi will get you sideways, but it's really slow. It's predictably sideways, so it can be used to teach you slide control. That becomes a hindrance as you get better at drifting and want to do more high speed skids.

I'm currently running no rear bar, 235-255 width rear tires at 30psi, and I still want more rear grip!
 
Initially a welded diff with a big bar and 60psi will get you sideways, but it's really slow. It's predictably sideways, so it can be used to teach you slide control. That becomes a hindrance as you get better at drifting and want to do more high speed skids.

I'm currently running no rear bar, 235-255 width rear tires at 30psi, and I still want more rear grip!

Thanks!
 
The 27mm hollow tube works out very close to the 25mm solid bar so comprable stiffness with less weight.
They have been on my dads donkey 240 for a couple of years and work perfectly fine on it. The balance feels good and much reduced body roll. Gaz adjustable dampers front and rear, 40mm lowering springs front and cargo springs rear.
I prefer a little less bar at the rear compared to front. 240's do not drive nice with no rear bar and the thicker the front one is the worse if feels and the more the car will sway and fish tail.
Anti roll bars are a final suspension refinement and does greatly come down to driver preference
 
It seems like a basic "How suspensions are tuned" might be in order with many of these threads. I am by no means an expert, but I have a pretty good handle of the maths involved and pretty decent practical experience if all you want is a car that handles well, and that you can exploit with confidence.

In a nutshell, suspension tuning is the science of managing weight transfer. Traction at the tire pretty much dictates how far you can go. Less traction? You have to have "softer" suspension. More traction? You need "stiffer" suspension. Obviously, there is a crapload more to it than just this, but it's a really, really good starting point. Got a 27mm rear bar on 205 section width Nankang Lion Claws or whatever? Yeah, I bet it's sketchy as hell. Likewise, running slicks with stock springs, shocks, and sways and I bet it rolls over like a 5 dollar prostitute when the sailors come to town.

It is, after all, called a suspension "system". It's about balance, grasshopper.
 
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