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Building your own ULTRA4, Stock Modified, Stock,  Legends, or UTV? Find out all the rules before you start your build. All safety rules must be followed by all classes.

Pro Comp Stock – 4600 - 8.3

Rubicon Expess Modified – 4500 - 8.4

G2 Wheels Legends – 4800 - 8.4.11

UTV Class - 4900- 8.6

4900 - UTV Drivers: Classes have been simplified to one class.  Please consult the ULTRA4 Rulebook section 8.6 for KOH UTV rules for KOH UTV Race.

Ultra4 Chassis & Tech Sheet can be viewed here.

Should you have specific technical questions, you must cite the section of the rule book to which your question pertains and email our tech inspector at