Using metal cable to attach defuser / undertray to chassis

[openwheeler37]

I would like to redo how my defuser and floor is secured to the chassis. Right now there are aluminum brackets secure the defuser and undertray to the chassis and it seems to stiff. I have noticed many cars using metal cable to accomplish this. What gauge cable is best and what is the best / cleanest way to crimp the cable ends? These http://www.officedepot.com/a/product...er=45799785716 seem to crude (and not very aero efficient) and these ... http://www.bettymills.com/shop/produ...Fc5DMgodiRUAUA... crimps require a special swaging tool. Thanks for the help.

[dereklola]

On my Lola F3000 the original Lola design used
- rigid fasteners for the diffuser (bolted into the gearcase), and
- cables for the side floors.

My assumption is that the diffuser is not likely to hit ground whereas the side floors are - using cable there allows a small upward deflection but the cables prevent downward deflection from ground effect downforce.

They have screw adjustment at one end similar to throttle cables - maybe they are (or could be) HD throttle cables.

Having said all that I replaced a couple of the cables with rigid aluminum strips (3/4 x 1/8 x about 12" long) and in spite of several 'groundings' there has been no permanent distortion - maybe they are thin enough to deflect slightly.

Regarding the ferrule type cable clamps - I used those to support my trailer shelves (with plastic covered cable!) - still OK after 10 years. Just used long handled pliers to crimp them.

[Purple Frog]

The diffuser to chassis connection should be very stiff.

Teams use cables to support the outer back corners of the diffuser to prevent downward deflection under high speed load..
One advantage to good strong cables is that they allow the corner of the diffuser to ride up over curbs, but never get too low when fully loaded.

The best do require special crimping tools. Shops that maintain sailboats also can build them, if you don't have a race supplier nearby.

[glenn cooper]

McMaster/Carr or Pegasus.
DONE!

[S Lathrop]

I have used aircraft cables and fittings to support the diffusers. 1/8 is my perferred size. See Wicks or Aircraft Spruce. I have a crimping tool that is required for crimping the cable ferrels. I use the tool to maintain farm fences. Same tool works for airplanes.

Having all that stuff, I like to use stainless strips instead. 3/4 wide by ,035 thick.

[JohnPaul]

zip ties and duct tape.......that's what Norm tells me....

[openwheeler37]

Thanks everyone! I will leave the diffuser solid mounted. The local hardware / farm supply store has a large assortment of stainless cables, crimps and accessories so I have access to the parts needed just wasn't sure what size cable and clamps to use. I will also check with Pegasus and McMaster ... If all else fails I guess it's zip ties and duct tape!

[dereklola]

I like to use stainless strips - 3/4 wide by .035 thick.

Do you just bend the end (when necessary) - or use a small angle bracket, yoke etc?

My Lola has some marvelous little end fittings which strike me as unnecessary complications.

[kea]

We've been making them the same way as our tension and push-pull cables for many years.
http://www.racing-stuff.com/control_cable.htm

[S Lathrop]

Do you just bend the end (when necessary) - or use a small angle bracket, yoke etc?

My Lola has some marvelous little end fittings which strike me as unnecessary complications.

Just bend and bolt works well enough. You could use a 1/4 thick aluminum block with a redius on one edge where the strap bends around the block.

[brownslane]

Here is a pic of the splitter supports I built with some off-the-shelf parts from Aircraft Spruce.

http://s241.photobucket.com/user/bro..._5685.jpg.html


The center barrel is threaded with LH on one side, RH on the other. The ends are left and right as well. So turning the turnbuckle one way tightens it, the opposite direction loosens it. Lock wiring ensures it doesn't change tension.


You can also have the ends swaged onto aircraft control cables, so you can build these to any length you like. I like the adjustability as you are guaranteed a nice tight fit, even as the parts may shift a little after a few races.

Tom