1st Gen RX7 rear lower links

[Tak]

Good conversation, and an example of what is wrong with the SCCA rules process. The conservative interpretation of the GCR tells us that it is legal to take a lower trailing arm/traction bar from a junk yard, remove a rubber bushing, and replace it with some precision machined sleeves and spherical bearings. But it is not legal to buy a readily available piece (circle track radius rod), that does exactly the same funtion as the heavily modified piece, costs less, and is easier to implement.
Doesn't this sound like the ECU rule? Or the Coil over rule?
Instead of focusing on liberal vs conservative interpretation, shouldn't we focus on updating a 30+ year old rule?

Let's go back to the intent of the IT rules. What was the intent of the original traction bar rule? I believe it was to enable solid axle cars to be lowered safely to the limits of the rules (and by safe I mean both reliability and functionally--a car that spits out drive shaft U-joints is not safe; neither is a car that has snap oversteer because of a bind or bottoming issue). Consider the rules allowance for cars of the time with semi-trailing arms (BMW 2002 and Datsun 510)--they are allowed to slot the trailing arm mounting points to correct camber and toe when the car is lowered. This is consistent with safely lowering the car per the definition above. Similarly, most of the solid axle cars of the day had axles located by leaf springs only. A means of lateral location was necessary for functional safety (predictable handling)--hence the panhard rule.

We would serve ourselves much better to develop basic intent of what the rules should be, rather than bickering about the rear suspension links of a now out dated and uncompetitive IT car. The ITAC took the first steps when they rewrote the overall class intent statement a few years ago. We need to help them help us by developing consensus on a reasonable list of high level intent. What is the intent of suspension modifications? What is the intent of chassis stripping? What is the intent of engine modifications? Stuff for a new thread...

Tak
#29 ITA (an Rx-7)
SFR, SCCA
And yes, my car has 5 traction bars locating the rear axle.

[ddewhurst]

***And yes, my car has 5 traction bars locating the rear axle.***

Mine did also. Two traction bars with foam bushings & three traction bars with adjustable rod ends. No one wrote paper, they looked, they smiled & they walked away thinking

[lateapex911]

Currently Tak, the rules allow you to take your stock arms and tack weld in spherical bearings, you don't have to machine cassettes or sleeves. In this circumstance, you do need some high clearance spacers, as i think you know.

Now, it is not legal to just add rod ends to the existing links after lopping off the ends.