||When did they change and for what class? usually they have a thicker wall ||ERW equivalent.
2004 GCR, announced in FasTracks sometime in 2003. Existing cages grandfathered, new logbooks require DOM
18.1.6. Material: A. Seamless, or DOM (Drawn Over Mandrel) mild steel tubing (SAE 1010, 1020,
1025) or equivalent, or alloy steel tubing (SAE, 4130) shall be used for all roll cage structures. Proof of use of alloy steel is the responsibility of the entrant.
Looks to me that, as another poster said, ERW is often called "seamless", then this paragraph would seam to allow ERW. look for a future "errors & omissions" addendum.
||> ||> Most race rules in the US call for the DOM product, not seamless. ||>
||> ||I have several rule books from several oval-track organizations in my ||shop. ||> || ||> ||While many mention "seamless tubing", I cannot find a single one that ||> ||specifically requires DOM. ||> || ||> ||Even my NASCAR Cup rule book states: ||> || ||> ||"20-17.4 Round, magnetic steel tubing 1-3/4 inches by 0.090 inch ||minimum ||> ||seamless roll-over bars are compulsory for the basic roll cage (diagrams ||#4 ||> ||and #5), and must be NASCAR approved. Aluminum and other soft metals not ||> ||permitted. Roll bar connections must be welded." ||> || ||> ||Admittedly, Cup car builders would prefer to use DOM over ERW, but in ||the ||> ||USA, ERW is considered to be "seamless", and - in spite of the previous ||> ||poster's statement - ERW would be acceptable since NASCAR does NOT ||> ||specifically require DOM. ||> || ||> ||And, the rule also puts to rest another old wives' tale in that the only ||> ||NASCAR requirement is that the roll bars be welded - not TIG welded, not ||> ||MIG welded...just welded. ||> || ||> ||Again, chassis builders will use what they believe to be the best ||process ||> ||for their own application. ||> || ||> ||Bob Paulin - R.A.C.E. ||> ||Race Car Chassis Analysis & Setup Services ||>
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