IHRA answers this part for 29 of its classes. 0 of those answers permit the part outright and 29 permit it with stated conditions, leaving 0 that do not.
This is one body's answer, not the sport's. You are bound
by whichever body sanctions the event you enter. If you race more than one
series, build to the stricter answer. The differences are set out in
the rulebook comparison.
29 classes, grouped where the same rule gives the same
answer rather than listed one by one, because an answer that holds for a class usually holds for every class
that borrows its rules.
Aftermarket ride plate: if the rule your class applies reads
differently to you, or the rulebook has changed since this was read, ask.
We answer with the section we read it from, or that we have not read it.
Ask a rules question.