A Guide to Sway Bars
How do I choose the correct Sway Bar for me?
Sway Bar choice and set up can be complicated, so here are some pointers to help you.
Why do I need different materials and what should I use?
Sway Bars are usually made in two different materials, 4340 and 300M.
4340 is a superb material and is used to make half shafts and Sway bars.It is a cost effective solution and can be heat treated. It has a good core strength and its elastic properties make it ideal for Sway Bars.(Gigglepin Racing use 4340 28 spline Sway Bars in Bad Penny).
300M is a level up and unequalled in strength and elastic properties, all our 35 spline Sway Bars are made from this material. Used in the very best race cars for half shafts and Sway Bars, it is the “go-to” material for those that need the very best. (Gigglepin Racing's Little Lady uses a 300M 35 spline Sway Bar).
What size Sway Bar do I need?
First choose which shaft size (28 spline or 35 spline) you require. As a pointer 28 spline (1.2”, 30.48mm) are used in most trail rigs, smaller race cars and in the front of bigger race cars as well. 35 spline (1.5”, 38.1mm) shafts tend to be used in bigger, heavier cars particularly for rear end applications.
'Bar Length' and 'Active Diameter' are the next things to consider. The diagram below shows how to measure your bar to get the correct length:
Overall Length is the total length of your Sway Bar, and you need to allow enough room to fit the bushings which are 1/4” (6.35mm) wide, and the arms which are 1.25” (31.75mm) wide. Don’t forget you need two of each.
Active Length is the working length of your bar and dictates the force the bar will deliver. This is calculated by overall length of bar, minus the spline length and bush seating area.
Active Diameter is the diameter of the Active Length and together they give you the power of the bar.
EG: The shorter the bar, the more powerful it will become. However, the shorter the bar, the less flex it will have.
Sway Bar Arms
There several choices for arms dependant on the length you require.
At Gigglepin we stock the most common arms used for 28 spline and 35 spline applications.
We can offer billet aluminium, steel self-build, or just the splined ends, dependant on your application.The longer the arm, the less power your Sway Bar will have.
You might still be a bit confused, so here is an example: Gigglepin Racing's Bad Penny uses a 4340 35” (889mm) 28 spline bar, with a 1” (25.4mm) Active Diameter and a 23.5” (597mm) Active Length. The arms are Comp 28 billet units, 15” (381mm) long, and use 10.63” (270mm) 7075 link arms, with 1/2” ball joints that are mounted halfway up the rear trailing arms. The mounting tube for this set up is: Length 32”(813mm), Internal 1.5” (38.1mm), External 1.75” (44.45mm).
There are also various Sway Bar poundage calculators on line that might help you.
Please note: bars do not come with bushings and these need to be purchased separately.
What Do I Need to Buy?
To build your Sway Bar kit you will need the following:
- 1x Sway Bar of your choice
- 1x Pair of Sway Bar Arms or Arm Builder kit components
- 2x Sway Bar Bushes
These can all be found on the previous page.
To complete your kit you will also need Sway Bar Links, Link Joints and possibly a Mounting Tube.
Contact Gigglepin if you need help finding these items.