[project] The Ultimate Track 205

[davenport 51]

Look forward to seeing it all assembled..

[Cameron 16]

I'll put up a CAD screenshot later so you can see what I mean.

[Cameron 16]

Both lower front wishbones done.

 

[Cameron 16]

Got the front upper wishbones done today.

 

 

 

 

I decided to TIG without a T-shirt on today, due to it being 17 million degrees in the unit, and now I have a reverse vest tan from where my mask shielded my neck. I look ridiculous.

[Para 82 2 Cars]

I don't know much about TIG work but I can still admire this and see how good that is

[davenport 51]

Lmfao......

 

 

lovely weather for welding hey!!!

[2052NV 24]

Im a total noob so sorry if this is a dumb question but why are the arms not on adjustable threads for setting up wheel alignment and tuning etc??

[Cameron 16]

Not a dumb question but I did explain a few posts ago. The only settings I need to change are camber and toe, and I have adjustable track rods for toe and shims between the upper wishbone clevis and the upright for camber. Using rod ends (rose joints) is heavier and weaker than plain sphericals, but also adjusting wishbone lengths changes more than just static camber and I don't want that.

[GeorgeXS 32]

To illustrate Cam's point on using shims between the upright and the upper wishbone clevis. The arrow shows the shim location on a similar setup, take away shims to increase negative camber, add shims to reduce it.

 

 

As Cam has said this method avoids changing the KPI (King pin inclination) and castor as the balljoint locations stay the same.

[2052NV 24]

ahhhh ic!

[welshpug 1,622]

simple and clever at the same time

[Cameron 16]

All the best ideas are!

I'll have a whole load of shims laser cut from different thicknesses of alooooominum, then have them colour coded so I can change settings easily without having to measure anything. Handily the combinations work out in 0.25Deg increments, or near enough.

Edited July 16, 2013 by Cameron

[allanallen 528 2 Cars]

No disrespect but doesn't your lack of adjustability mean the space frame needs to be absolutely bang on to get your wheelbase, width etc correct? It's all well and good making shims to 2 decimal places but fabrication generally isn't that accurate.

What's the plan if you 'tweak' the frame in an off or being a bit over enthusiastic over a kerb?

[Cameron 16]

Yeah it does but I'd have a tolerance on wheelbase & track much the same as any production car would, albeit a little tighter. The space-frame would need to be bang on in order to have identical geometry side-side with adjustable wishbones, so it just depends which one you want to have a tolerance on - track / wheelbase or suspension geometry & kinematics. If you look on any decent race car (single seaters especially) you won't find rod ends on the wishbones, especially not at the outer balljoints.

 

Hopefully I won't be having any accidents big enough to bend the chassis, but if I do I imagine I'll have to get it on the jig to cut off & re-make the damaged sections. The wishbones are weaker than the frame, so in minor accidents will just bend.

 

The shims are standard wire guage and metric in commonly available sheet metal thicknesses - 0.91mm = 20swg, 1.63mm = 16swg etc etc.

Edited July 16, 2013 by Cameron

[johniban 59 1 Cars]

i was going to say, you have all the jig, and i guess you are going to keep it incase you to damage the chassis?

[Adrian W 0]

There have been a few instances lately here in australia of Elise's breaking the bolts shown in the above picture. I don't think aluminium should be used as it can crush with an impact and let the bolts slacken a little and then break when the load increases. Elise's use steel shims in that spot.

[Cameron 16]

I'm not all that surprised looking at the offset between the UBJ and the mounting point, and also the clamped area. My upper clevis mounts in double shear and has zero offset as well as a much larger area, so hopefully it will be ok to use aluminium shims. Time will tell, I guess; I can always swap to steel shims if I have issues, they're very simple laser cut parts.

[Toddy 7]

How come no bracing bar between the wishbone?

[welshpug 1,622]

I'd guess its been designed properly so doesn't need one

[Rippthrough 98]

I'd guess its been designed properly so doesn't need one

 

This.

 

If your joints are loaded correctly you don't require one, it's triangulated by the chassis.

[Cameron 16]

Amen to that.

 

In other news, I PICK UP MY GEARBOX TOMORROW! :D

[Rippthrough 98]

And then drop it on your toes when he hands you the bill?

[EdCherry 34 1 Cars]

The bracing bar you see between wishbones is often anti-intrusion into the chassis rather than to add any triangulation, certainly with proper race cars.

 

I would have personally gone for rod ends after working with numerous space framed and monocoque chassis, the ability to correct faults within the chassis in production is a big help. I haven't found a car yet that measures up within an acceptable tolerance.

 

I personally can't see any reason why you would have a problem with using the aluminium shims. Once again from previous experience with numerous race cars that use that setup I have only ever used aluminium and only been supplied aluminium by the manufacturers.

 

Keep the good work up Cam.

[Cameron 16]

Cheers Ed, will be buying dampers soon btw.

[EdCherry 34 1 Cars]

Sounds good, might have some internal bits you could be interested in!