Rollcenter Correction Clarification
#25873 from Bill Lamkin · Rule change · TB 19-04 (2019-04 Fastrack)
Note from CRB: 9.1.5.E.5.b.2 in “Suspension and Steering Level 2: Suspension Components”
states that “Suspension control arms, bushings, bearings, and ball joints are unrestricted.”
However, allowance to ream out ANY tapered hole from a stock ball joint does not exist, unless
being done to a specifically unrestricted component, like a suspension control arm. This is not
the intent to restrict in that manner, and should be clarified:
In GCR section 9.1.5.E.5.b.2, add wording as follows:
“Suspension bushings, bearings, and ball joints are unrestricted. Tapered holes can be drilled
or reamed, to allow a bolt to be used in place of a ball joint.”
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Note from CRB 9.1.5.E.2.o.5 in “Final Drive” states that “Axle shafts, bearings, bearing
carriers, hubs, and universal joints/CV joints are unrestricted.” Therefore any of those items,
all of which are defined in the GCR, that are part of the final drivetrain system of the vehicle,
are indeed unrestricted. However, this rule would not apply to a non-driven axle, as it is not
part of the drivetrain. It is agreed that allowing unrestricted bearings and hubs should not be
limited to only the driven axle, and it should be applied to both axles/at any wheel:
In GCR section 9.1.5.E.5.b. add wording as follows:
“6. Wheel bearings and hubs are unrestricted.”