Pass TECH?

[RICK]

As I recall, the rule book states that all rear suspension members/links are required to have a 1/4 inch metal "sling".
     I got this 5/16 surplus cable that came from BOEING aircraft,  Is that going to be enough to get me through the Tech Inspection?


       Thanks    RICK

[Sumner]

Rick I'm glad you brought this up as I'm going to have to do something also and forgot all about it .

I lightened the picture up a little as I was having a hard time seeing exactly what you had done.  I'll be interested in the answer.

c ya, Sum

[JackD]

Does the fastening method match the strength of the suitable material ?
A double wrap around the object and then to the same fastener would be stronger with out a lot of stuff.

[Bob Drury]

Rick, the first thing I would do is get rid of the triangulated link, and install a panhard bar.  Those things are meant for drag racing only.  If you read any reputable chassis manufacturers catalog, they state that the triangular link is Not for street or any application other than straight.  If your car gets sideways, the stress on that bar becomes almost unthinkable.........................

[Bob Drury]

Rick, in looking at your four link brackets, it appears that you could attach a flat bar loop bracket from the lowest attachment hole of the upper four link bar, and drop it down under the lower bar.  The upper bar shouldn't need anything, because the bolt thru the lower hole (holding the new loop bracket) would prevent it from coming out of the upper bracket.

[interested bystander]

Mr Drury is absolutly on target re his advice to scrap the triangular link- it's a drag race only adaption (although it does work like a panahrd bar- but has NO side load strength)- Panhard bars are good enough  for NASCAR, although a Watts linkage is probably more exact -but not "tunable" as a panhard bar for roll center changes and wheel loading.
Because the lower 4 link bar essentially does the "pushing" of the car down the course-I'd favor adding diagonal link forward up to the main frame from somewhere near the bottom of the lower attachment holes of the 4 link bracket to transfer the "push" load into the main structure.

[hitz]

Rick,
  I think your cable idea has advantages over the strap method. I believe the straps are meant to keep the arm from falling on the ground and pitch poling. Once the axle moves back from from the point of failure it can fall out from a strap. With a more forward mounted cable anchor it would even limit the amount the axle moved back.
  When using cable clamps the "u" bolt part of the clamp goes over the short "dead" end of the cable, not the saddle part. The old construction saying is" you never put a saddle on a dead horse".
  Lots of street rods use triangulated upper bars and no other triangulation. They don't pull the axle sideways when it articulates either!

  Of course at speed, if a heim or anchor bolt breaks it might not make a lot of difference because it is not going to be going straigt any way!!
 
  Harv

[SPARKY]

Guys, by definition SLING denotes two side parts--not one and a clamp---the sling has to be mounted far enough from the end, and the "sling" mounted in such a way as there can be no "ESCAPE"---it needs to be a separate piece and attachment point---year before last---someone got to go home with out running over this very subject...---

a very ROOKIE inspector...

[Bob Drury]

Hitz, when you speak of street rods using upper four link triangulation, yes they do, with "both uppen bars triangulated", not a single, diagonal link.  As I stated before, no reputable chassis manufacturer will recomend a single diagonal link for obvious reasons.  If and when a diagonal link should break, the rear end housing will probably leave the premiss, if you get my drift..........................

[jimmy six]

I can not see the top one very well but from the pictures, if I was inspecting your car I would let it run...Both bars need to be protected and the front trianglular one may need protecting too depending on the inspector.. Good Luck..(I won't be there to do it so I would do everything; remember the rules are just the minimum) J.D.

[RICK]

If the intent of this rule is to keep a suspension member from contacting the track surface if it were to fail?,,,,Then I feel comfortable in my attempt to comply.

 Lets face it,,,the rule book is written to keep us SAFE and play fair. Its GOOD. But at times can be vague.   That why we have these forums, poles, questions,etc.,,,,

  In my application, 'four link', the bottom bar is in compression and the top bar in extension. If one was to break, it could be held up off of the track surface with a simple piece of 8lb test fishing line.
  So my 5/16  cable is kinda overkill.
  As far as the diagional link goes,,, it would only fall as far as on top of the driveshaft.


     thanks,   RICK

[russ jensen]

not quite on subject; however... lower arm front mting bracket appears to need some help. looks like it needs a brace or gusset to   cross tubing to keep it from bending for & aft and a angle brace of small diam tubing  for sideways stability.  side note, the angles of the 2 arms  as setup in pic will probably result in no supension at all under load, fought this in stock car forever, rember misery is porportional to the number of holes in  mtng bracket.

[jimmy six]

Rick, I only mentioned the cross link because in a catastrophic failure the drive shaft may also be missing.. I know other very thorogh inspectors would also mention it. J.D.

[hitz]

Lots of good info and food for thought on this thread.

  That's the best thing about this forum! This type of banter helps the new builders (like me) a great deal. Keep up the good work!

  Harv