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Old 04-13-2020, 08:41 PM
Tim White Tim White is offline
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Default Rear Trailing Arm

I posted this on the Facebook page as well.

This is just horrible rule writing:

9.1.6. American Sedan (AS) Specifications
GCR - 528

Original unmodified lower control arms (front and rear), and original unmodified front upper control arms must be retained. Vehicles with rear trailing arms may replace OEM arms with tubular arms. Arms must maintain stock length and serve no other purpose than locating rear axle assembly.

What is the difference between a rear lower control arm and a rear trailing arm? This is the only place in the AS rules that mention rear trailing arm and there is no definition. Control arm on the other hand is used over and over and is defined as such:

Suspension Control Arm – A beam or frame intended to limit the normal motion of the affected suspension part to predetermined paths.

If the intent is to allow any lower control arm of stock length then change the rule to actually say that. Don't make contradicting statements.

Last edited by Tim White; 04-13-2020 at 08:49 PM.
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Old 04-13-2020, 08:52 PM
Tim White Tim White is offline
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I see that trailing arm is defined as:

Trailing Arm A wheel control linkage locating the wheel in the fore/aft direction, which is attached to the car structure at the forward end of the arm, and to the wheel carrier at the rear of the arm.
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Old 04-13-2020, 10:50 PM
MarkMuddiman MarkMuddiman is offline
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There is a problem with the rule for the fox and SN95 Mustangs.
The stock arm also carries the stock anti-roll bar.
The rule doesn't allow stock anti-roll bars to attach to tubular arms.
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Old 04-25-2020, 04:35 AM
DHRMX5 DHRMX5 is offline
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Quote:
Originally Posted by Tim White View Post
I see that trailing arm is defined as:

Trailing Arm – A wheel control linkage locating the wheel in the fore/aft direction, which is attached to the car structure at the forward end of the arm, and to the wheel carrier at the rear of the arm.
Control arm is for straight axle.

Trailing arm is for IRS, based on this part of your post: "and to the wheel carrier at the rear of the arm"

Last edited by DHRMX5; 04-25-2020 at 04:40 AM. Reason: clarification
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Old 04-25-2020, 02:39 PM
MarkMuddiman MarkMuddiman is offline
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"Control arm" is a more generic term than "trailing arm", like finger and thumb a trailing arm (thumb) is a specific type of control arm (finger).

Similarly, "wheel carrier" is more generic than "straight axle" - a live axle housing is a wheel carrier. The example in the SCCA definition might be a little misleading since the term "wheel carrier" is not normally used for a solid axle.
Definitions of suspension components is confusing, as there are multiple names for the same things. As suspensions get invented, new names get created for specific angles, directions, shapes...
Between us we've used 3 terms for the rear axle (now 4). "Stick axle" makes 5.
Even using the term "axle" is potentially inaccurate and confusing. For a full floater, the hub is the "wheel carrier" but it is in turn carrier by the housing. The axle shaft plays no role in locating the wheel.
For a conventional setup (I don't even know if there is a term for non-floater) the integral axle/flange does actually carry the wheel, but it is part of an assembly including the housing that together make up the "wheel carrier".

So the rule text is actually accurate, but if you don't already know this, it's tough to figure it out.
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Old 04-25-2020, 02:47 PM
jimwheeler jimwheeler is offline
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This wheel hasn't been carried in a long time. don't be talking about the wheel like that.
signed, wheel
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