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Sway Bar Tech

rattle_snake

rattle_snake

Fuckwits
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Chandler, AZ
Didn't find a thread specific to sway bar tech so share some info, pics or experience on:
  • Selecting bar diameter and arm length (given application and use)
  • Tuning
  • Link length, arm angle
  • Mounting and packaging to clear
    • track bar mount
    • steering box
    • Big tires at lock
  • Reuse of OEM sway bars
  • Making your own (materials, methods)
:flipoff2:
 
Bar diameter is only part of the equation. Arm length and length of the bar also play a part in the rate. This is a chart from Speedway Engineering. Values are calculated at 5 degrees of twist on an Intercomp sway bar tester.
37-1/2" X 1" — 48 Spline Solid Sway Bars
8"8 1/2"9"9 1/2"10"10 1/2"11"11 1/2"12"12 1/2"13"13 1/2"14"14 1/2"15"
3/4"11010497938984807673716865636159
13/16"14914113212512011310810399959188858279
7/8"193182171163155147141134129124118114111106103
15/16"237224210200191180173164158152146141136131127
1"276261244233222210201191184177169164158152147
1 – 1/16"334316296282269254244232223215205198192184179
1 – 1/8"393372348331316299289272262252241233225217210
1 – 3/16"447423396377360340326310298287275265257246239
1 – 1/4"519491459437417395378359346333318308298286277
 
37-1/2" X 1-1/4" — 49 Spline Solid Sway Bars
8"8 1/2"9"9 1/2"10"10 1/2"11"11 1/2"12"12 1/2"13"13 1/2"14"14 1/2"15"
3/4"1231161091049993908582797573706866
13/16"1601511421351291221171111071039895928885
7/8"206195182173166157150143137132126122118113110
15/16"263249233222211200192182175169161156151145140
1"320303284270257243233222213206196190184176171
1 – 1/16"389368344328313296283269259250239231223214208
1 – 1/8"460435408388370350335319307295282273264254246
1 – 3/16"546516484460439415398378364350335324313301292
1 – 1/4"617584547520497470450428411396379366354340330
1 – 5/16"734691652618587559534510490470452435420405392
1 – 3/8"864812768727691658628601576553532512494477461
1 – 7/16"1000941889827800762727696667640616593572552534
1 – 1/2"114010731013960912869829793761730703676653629609
 
37-1/2" x 1-1/4" — 49 Spline Hollow Sway Bars
8"8 1/2"9"9 1/2"10"10 1/2"11"11 1/2"12"12 1/2"13"13 1/2"14"14 1/2"15"
.91"12712011310710297938885827875737068
.94"1601511421351291221171111071039895928885
.97"191181170161154146140133128123118114110106102
1.0"226214200190182172165156150145139134130124121
1.03"257243228217207196188178171165158153148142137
1.06"296280262249238225216205197190182175170163158
1.09"331314294280267252242230221213204197190183177
1.12"379358335319305288276262252243232225217209202
1.15"426403377359343324310295284273261253244235227
1.18"464439411392374353339322310298285275266256248
1.21"510482452430410388372353340328313303293281273
1.25"553523490466445421403383369355339328317305295
1.31"704666624594567536514488470452432418404388376
1.38"829784734699667630604574552532509492475457443
1.44"893845791753718679651619595573548530512492477
1.50"957905848807770728698663638615588568549528511
 
I’ll have to find the sway bar calculator I used but you input length of the bar, diameter and length of arm.

My front sway bar is super soft, like 50 lb spring rate. I figured it wanted it to take up some sway on road but not too much off-road.
 
PXL_20220126_231400103.jpg
 
06h3 its the first one I've seen mounted on the front axle. Seems to work well
 
No idea. Im sure someone much smarter then me can chime in
 
Very cool topic, it'll be fun to follow along

gt1guy said:
How do you figure out how many lbs of bar rate are needed to hold X degrees of body roll?
Click to expand...

The reality is it's pretty hard to make any direct connection like that, due to the context of each build being so different than the next. The primary factors on the bar config itself are the bars primary rate, the length (motion ratio) of the arms, and the angle of the arms from horizontal (viewed from the side). Any of those 3 variables changing impact the amount of force the bar is applying through the end links in any given configuration.

Then on the body side, you have sprung weight, spring rates, and how close the front and rear roll centers are to the center of gravity. Any of those 3 variables changing dictate by how effective that force from the bar is applied to the chassis.

All that basically saying the same bar rate will act differently in every chassis. So for those of you willing to share details about your rig, the more technical details the better to understand what's really happening! :beer:
 
gt1guy said:
How do you figure out how many lbs of bar rate are needed to hold X degrees of body roll?
Click to expand...
Math, lots of math.:flipoff2:

If you have the ability to solve articulated suspension geometry, know spring rates, slider stops, cg, weight, sway bar arm length, sway bar tube length, g force (or side hill angle), you can create a curve showing bar rate vs roll angle.
 
Maybe I am wrong, so feel free to correct. I do not recall the exact number, but most bars do not like to twist very far, before breaking. Because of that, you can take the amount of twist, and calculate the arm length, to allow the full amount of travel in the suspension.
 
Has anyone built a sway bar that the arms double as cantilever arms for shock packaging? A friend and I were bench building talking about the concept recently
 
posford said:
Has anyone built a sway bar that the arms double as cantilever arms for shock packaging? A friend and I were bench building talking about the concept recently
Click to expand...
Yeah it's been done, and it's super nifty. People have used full front wheel hubs for cantilever pivot points, then run a sway bar between them with slugs or locking hubs to engage/disengage the sway bar. My old cantilever buggy I never finished was set up like that front and rear with turned down kingpin 60 hubs. I'd definitely use unit bearings these days though, probably the same ones I would run on the axles

IMG_0017.JPG
 
AgitatedPancake said:
Yeah it's been done, and it's super nifty. People have used full front wheel hubs for cantilever pivot points, then run a sway bar between them with slugs or locking hubs to engage/disengage the sway bar. My old cantilever buggy I never finished was set up like that front and rear with turned down kingpin 60 hubs. I'd definitely use unit bearings these days though, probably the same ones I would run on the axles

IMG_0017.JPG
Click to expand...
What did you plan to use for the actual bar that had a matching spline count? Or plan to hob a spline on whatever you bought?
 
posford said:
What did you plan to use for the actual bar that had a matching spline count? Or plan to hob a spline on whatever you bought?
Click to expand...
Just a 35 spline axle shaft. Turned down as needed, but at least in the rear it was a very long bar with long arms so I was going to start at the spline minor diameter.

Bebop, that's a cool setup I haven't seen before. Was there a build on it, forum or SM?
 
Treefrog said:
That definitely an interesting set up. Any idea on travel numbers?
Click to expand...
They keep it pretty tight.

It's a massive, professional effort to win the Ultra4 Europe championship.

AgitatedPancake said:
Bebop, that's a cool setup I haven't seen before. Was there a build on it, forum or SM?
Click to expand...

It's all here :

www.facebook.com

Reulsport Offroad team

Reulsport Offroad team. 2,126 likes · 137 talking about this. Nous sommes actifs dans la compétition automobile tout terrains
www.facebook.com www.facebook.com

They don't share many infos.
 
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