My Elio Alternate Project Is Underway.

[84mpg]

Cutting Rear Axle Beam:

Existing, large car manufacturer: “We need to have our engineers study the best approach. We’ll scan it, model it and do some simulations. We’ll need to run it by some teams and get their input. Might be next quarter before we can reach agreement where to make the cut on the beam”

Mark: “I’ll cut it right here and make it work...”

 

[JEBar]

sounds about right ...

 

[Mark BEX]

Cutting Rear Axle Beam:

Existing, large car manufacturer: “We need to have our engineers study the best approach"

I don't think there was much engineering going on with that beam, darn tube is 5mm thick (almost 1/4")!

It's 60mm/2.3" diameter, they could have easily gone for say 75 x 3mm/3" x 1/8", which is a tube size for many RWD rear axles tubes, and would have been lighter, but stronger. 2mm would be fine even, but you are at long term rust risk then.

It coincidentally is the same size tube as they use for the link bush casings for it, red arrows, like someone said "One size for all" ... that part may work out well for me yet, as I may use those bushes in the left over tube after I have cut the 2 ends off, we will see.

 

[Mark BEX]

Working out a rear swingarm, for the rear wheel of course.

Couldn't be a more simple design really, a couple of lasered extra brackets for the 2nd swing arm,

... which are simply 2" box tube, and another 2" box tube up front across the chassis.

Just working out the hard part, swingarm bushes, hoping some Toyota HiLux ones are going to work out :-).

 

[Mark BEX]

Had a good find today for the rear swingarm bushes, and for many projects into the future.

I have wasted countless hours looking for a good bush for control arms and trailing arms over the years, there is so many of them, and the manufacturers seem hell bent on not using standard sized tubing for the casing, and that's the issue, the casing.

Well, here is my answer, the Chev Colorado, 2004 to 2012, 2WD upper control arm bushes. Perfect.
My tube here is common 48mm x 2.5 wall, one of the most common sizes around, also the next thickness up, 3.2 mm, is a World standard for scaffolding tube.

My tube is only a light hammer tap fit, which is too loose for a bush, but after welding the casings into place, the welding will shrink it to a press fit.

 

[Mark BEX]

This is roughly what the rear end looks like, a bit blocky looking in this 3D though.
I don't need "Ohh, pretty!" at this stage, so bear it

It will be pivoting on the rear roll cage legs, pink here.

 

[84mpg]

I've wondered... When there's a setup like this, does it put more stress/forces on one side the the frame (roll cage in this case) than say a 4-wheeled vehicle? I guess the amount of stresses would be about the same as a 4-wheeled independent suspension vehicle, right?

(Just "looks" like there's a more possibility of flexing, twisting, etc...)

 

[JEBar]

I'm looking forward to seeing how you will rig up the suspension for the rear tire

 

[Mark BEX]

I've wondered... When there's a setup like this, does it put more stress/forces on one side the the frame (roll cage in this case) than say a 4-wheeled vehicle? I guess the amount of stresses would be about the same as a 4-wheeled independent suspension vehicle, right?

(Just "looks" like there's a more possibility of flexing, twisting, etc...)

No. it's a very basic 3D without any bracing, don't look too much into it.

It is even more important on a reverse trike to have secure alignment of the rear wheel at all times to prevent rear steering. One of the reasons the front tube is so wide, is to minimise angular movement through having the pivot bushes spaced as far apart as possible.

I'm looking forward to seeing how you will rig up the suspension for the rear tire

I'll bounce something in there.

I'm hoping to use a front strut at the rear, I figure the basic weight distribution will be aprox 66/33, eg; same spring rate for all 3 wheels. I see already I have options to change the motion ratio simply by putting the strut forward, or rearward of the axle line, so not too worried.

 

[JEBar]

I'm hoping to use a front strut at the rear, I figure the basic weight distribution will be aprox 66/33, eg; same spring rate for all 3 wheels. I see already I have options to change the motion ratio simply by putting the strut forward, or rearward of the axle line, so not too worried.

I like the strut idea .... with the motor and driver so far forward, I'd of thought the weight distribution would have been higher than 66 ... that said, I'm sure you will adjust accordingly