IHRA answers this part for 29 of its classes. 29 of those answers are permissions, with or without limits attached, and 0 are not.
This is one body's answer, not the sport's. You are bound
by whichever body sanctions the event you enter, and where both govern you,
you are held to the stricter of the two. The differences are set out in
the rulebook comparison.
Where it stands, class by class
29 classes, grouped by the answer rather than listed one by
one, because an answer that holds for a class usually holds for every class
that borrows its rules.
Legal, within limits 27 classes
Replacement bumpers and side rails may be used provided they create no hazard. A permanently affixed nose bumper remains required. · J.13, I.17
DD.1 says exterior bumpers are not required, while I.17 requires a permanently affixed nose bumper on every craft not originally built without one, and section DD never claims to override section I, so ask the series before removing anything. · DD.1, I.17
DD.3 waives exterior bumpers for this class, where I.17 still requires a permanently affixed nose bumper, and nothing in section DD says it displaces a section I safety rule, which leaves this unresolved rather than permitted. · DD.3, I.17
Replacement bumpers and side rails: 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.