I've always called 'em clamping rings. What they're for is stock wheels that aren't lug-centric - they're hub centric so they have flat lug holes instead of conical seat. You put the rings on, and the rings have like 60 degree conical lug seats that take the stock style lug nuts.
Pretty sure every dually truck in the GMT400 style body uses them with stock wheels. Even my '94 3500HD uses them...in 10 lug.
Richard
Post was last edited on Dec 27, 2011 02:05. Edited 1
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