On each corner, I have two lower links, and one trailing arm. They all weigh the same, at 555g including the threaded ends.
I got to thinking – can I save weight by going to t45 or even mild steel. The answer is a strong yes, for little machining/fabrication effort.
The table below shows the comparison between what I have now, moving to mild steel and T45
The summary is I will save 1.5 kg. Not only that but half of that is unsprung mass as well. All of it is suspension mass, so whenever the wheel moves, it has to. This is a bonus. More T45, Vicar. NOW.
In the spirit of “if you’re going to change anything, change EVERYTHING”, I have almost finished the brackets for the height-adjustable suspension. As well as making the suspension height-adjustable, I’m junking the old wishbones for the following reasons:
- I’m going to t45 oval tubing for extra strength
- I’m going to spherical bearings rather than bushes (ugh – bushes)
- I want to make the suspension height adjustable so I can lower it when I need to
The welding rod here shows the line of force that actually happens, and the angles it has to go through. Firstly nearest you is the angle through the bottom ball-joint. That’s quite severe. the second is at the chassis bracket where it will have the bracket under torsional force.
In order to get the bracket just where I needed it, and at 90 degrees to the line of force I made a simple jig – one hole to locate against the ball joint, and one there the bracket bolt goes through. The jig was machined to be a tight 90 degree fit against the bracket so it would always be perpendicular to the line of force.
And here it is up close. The wishbone will have a 3/8ths spherical bearing that slots into the bracket there, and then the bracket can be height adjusted by moving it up the slots.
The bracket is then reinforced at the back and welded to the chassis.
So, Julian took a look at the brackets (from afar, through this site) and called “that’s a bit heavy looking”. I did a bit of thinking, and got the grinder out. The results are below:
- Original Weight: 380g
- chopping 5mm from the outer face and changing the chamfered corner: 60g
- polishing out the welds: 20g
- chamfering the long edges: 10g.
So the end result is a reduction in weight of 24%. Worth the effort for a few minuets work. Now… to the personal diet.