For the most part I agree with your comments. A few things to add though.
1. The equivalent of SP would be Improved Touring, not Touring. Touring in
Club Racing is more like Stock.
2. The IT rules already restrict cages to 8 points. 6 to the floor (main
hoop, front hoop, and two rear supports) and 2 forward to firewall (but not
forward to suspension). The rules also allow unlimited bars in between
these points. Taken to extreme, this can be advantageous.
3. Reconciling SCCA rules with NHRA rules is next to impossible. Either
could change at any point without input from the other body. The NHRA rules
for cages already disallow Autopower style bolt-in cages. "All required
rear braces must be installed at a
minimum angle of 30-degrees from vertical, and must be welded in. Side bar
must pass the driver at a point midway between the shoulder and elbow." My
IT and SP legal Autopower cage does not meet the requirements quoted above.
Alistair Hastings
----- Original Message -----
From: <dg50@daimlerchrysler.com>
To: <autox@autox.team.net>
Sent: Wednesday, October 11, 2000 12:24 PM
Subject: Roll Bar Rules Changes - Serious Stuff Here!
> OK gang, I've got something serious to discuss today.
>
> The roll bar rules we have currently, suck.
>
> As far as I can tell, we have:
>
> - a ruleset for Stock
> - a ruleset for Street Prepared (and thus SM by inheritence)
> - a ruleset for Showroom Stock road racing
> - a ruleset for whatever the SP equivelent is for road racing (Touring?)
> - a ruleset for the NHRA
>
> It would be a Very Good Thing if the rules for roll bars/cages could be
> unified in such a way that there was a clear and obvious progression and
> cross-legality between roll structures. To wit:
>
> 1) Stock class and Showroom Stock road racing should share the same rules
> 2) SP, SM, and Touring should share the same rules
> 3) An NHRA legal bar/cage should be legal in SP and SM, and it would be
> nice if it could be made legal in Stock class too.
>
> Here's the major bullet points:
>
> - Roll structures should be considered safety equipment. While it is true
> that there may be some performance-enhansing chassis stiffening going on
> (and the rules should be worded to restrict this performance enhansing
> aspect as much as possible without compromising safety - a roll structure
> should not be a "must have" performance-enhancing item for autocross) the
> main point of a roll structure is to protect the driver in case of the
> shiny side going down.
>
> - The likelyhood of an event ocurring at an autocross that would require a
> roll structure to defend against is fairly low. However, many autocross
> cars see double or triple duty as drag cars and track day cars. (I see few
> autocross/road race cars outside of Prepared) The NHRA requires a roll bar
> at 11.99 or faster. Most track day (Solo 1) sanctioning bodies require
some
> sort of roll structure. Nobody's car should be made illegal for Solo
> competition because they added a piece of safety equipment.
>
> - While there is a performance aspect to the installation of a roll
> structure, there's also the weight consideration. Any roll structure is
> going to add roughly 70 lbs to a car. With this in mind, minor interior
> trim removal etc. to accomodate the bar is a non-issue performance wise.
>
> Here are the NHRA regs for roll structures, edited for applicability (ie,
> no dragsters, sub-9 second cars, etc)
>
> ------------------------------------------------------------
>
> 4.10 ROLL BARS
>
> All roll bars must be within 6-inches (15.2 cm) of the rear, or side, of
> the driver's head, extend in height at least 3-inches (7.6 cm) above the
> driver's helmet with driver in normal driving position, and be at least as
> wide as the driver's shoulders or within 1-inch (2.5 cm) of the driver's
> door. Roll bar must be adequately supported or cross-braced to prevent
> forward or lateral collapse of roll bar. Rear braces must be of the same
> diameter and wall thickness as the roll bar and intersect with the roll
bar
> at a point not more than 5-inches (12.7 cm) from the top of the roll bar.
> Sidebar must be included on driver's side. The side bar must pass the
> driver at a point midway
> between the shoulder and elbow. All vehicles with OEM frame must have roll
> bar attached to frame; installation of frame connectors on unibody cars
> does not constitute a frame and therefore it is not necessary to have the
> roll bar attached to the frame. Unibody cars with stock floor and firewall
> (wheel tubs permitted) may attach roll bar with 6-inch (15.2 cm) x 6-inch
> (15.2 cm) x .125-inch (3.2 mm) steel plates on top and bottom of floor
> bolted together with at least four 3/8-inch (9.53 mm) bolts and nuts, or
> weld main hoop to rocker sill area with .125-inch (3.2 mm) reinforcing
> plates. All 4130 chrome moly welding must be done by approved TIG Heliarc
> process;
> mild steel (or ST51) welding must be approved MIG wire feed or approved
TIG
> heliarc process. Welding must be free of slag and porosity. Any grinding
of
> welds prohibited. See illustration (Drawing 12).
>
> Roll bar must be padded anywhere driver's helmet may contact it while in
> driving position. Adequate padding must have minimum 1/4-inch (6.35 mm)
> compression or meet SFI Spec 45.1.
>
> 4.11 ROLL CAGE
>
> All cage structures must be designed in an attempt to protect the driver
> from any angle, 360-degrees. All 4130 chrome-moly tube welding must be
done
> by approved TIG heliarc process; mild steel tube welding must be approved
> MIG wire feed or TIG heliarc process. Welding must be free of slag and
> porosity. any grinding of welds prohibited. Additionally, roll cage must
be
> padded any where the driver's helmet may contact it while in the driving
> position. TAD, TAFC, Pro Stock, Funny Car & Top Fuel padding must meet SFI
> Spec 45.1.
>
> Open Bodied cars
>
> When driver is in driving position in an open bodied car, roll cage must
be
> at least 3-inches (76 mm) in front of helmet.
>
> Full Bodied Cars
>
> On full bodied car, with driver in driving position, helmet must be in
> front of main hoop. If helmet is behind or under main hoop, additional
> tubing same size and thickness as roll cage must be added to protect
> driver. Main hoop may be laid back or forward but driver must be
> encapsulated within the required roll cage components.
>
> All cage structures must have in their construction cross bar for seat
> bracing and as the shoulder harness attachment point; cross bar must be
> installed no more than 4-inches (102 mm) below, and not above, the
driver's
> shoulders or to side bar. All required rear braces must be installed at a
> minimum angle of 30-degrees from vertical, and must be welded in. Side bar
> must pass the driver at a point midway between the shoulder and elbow.
>
> Swing out side bar permitted on O.E.M. full bodied car 7.50 (*4.50) E.T.
> and slower. The following requirements (a through d) will be enforced on
> cars certified after 1/1/98, on all cars 1/1/99.
>
> a. 1 5/8-inch (41.2 mm) O.D. x .083-inch (2.1 mm) (CM) or .118-inch (3.0
> mm) (MS) minimum. Bolts / pins must be 3/8-inch (9.5 mm) diameter steel,
> minimum and in double shear at both ends.
>
> b. Male or female clevis(es) permitted. Male clevis must use two minimum
> 1/8-inch (3.2 mm) thick brackets (CM or MS) welded to each roll cage
> upright; female must use minimum 1/4-inch (5.4 mm) thick bracket (CM or
MS)
> welded to each roll cage upright. Pins must be within 8-inches (204 mm) of
> the vertical portion of both the forward and main hoops. A half cup
backing
> device must be welded to the vertical portion of the main hoop (inward
> side) or the upper end of the swing out bar (outward side), minimum
> .118-inch (3.0 mm) wall (CM or MS) extending at least 1 5/8-inch (41.2 mm)
> past the center of the pins. A clevis assembly utilizing a minimum
> .350-inch (8.90 mm) thick male component and two minimum .175-inch (4.45
> mm) thick female components may use a 1/2-inch (12.7 mm) diameter grade 5
> bolt, and does not require a half cup backing device.
>
> c. Sliding sleeves of 1 3/8-inch (35 mm) x .083-inch (2.1 mm) CM or .118
> (3.0 mm) MS, with minimum 2-inch (51 mm) engagement, are permitted in lieu
> of the upper pin/cup.
>
> d. All bolt/pin holes in the swing out bar must have at least one hole
> diameter of material around the outside of the hole.
>
> ----------------------------------------------------
>
> Based on this, and my (admittedly sketchy) understanding of the road
racing
> GCR, it seems that the following criteria should be acceptable:
>
> 1) For Stock class, any bar of up to 6 mounting points (main hoop, two
> rearward main hoop supports, two forward main hoop supports, which may or
> may not have an additional front hoop which may tie into the rear hoop but
> not connect to the chassis at any other point) bolted in using sandwich
> plates.
>
> 2) For Street Prepared and Street Modified, as per Stock Class but with
> welding of the attachment points permitted
>
> Comments? Can anybody see any contradiction between what the NHRA wants
and
> what the GCR requires?
>
> DG
>
>
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