FORMULAVEE.ORG

I've got rear drums that measure 9.14" compared to the max diameter stamped on the drum of 9.113". Time for new drums?

Mike

The GCR rules allow you to exceed wear parameters in the shop manual (or anywhere else) as you see fit (except for those parameters specifically mentioned .. like Cylinder bore diameter). If they are working fine and don't cause any other problems, no need to buy new ones .. yet .
Steve, FV80

Thanks Steve. I have not put them on since they were surfaced but they were OK before. I just want to be sure they are safe to run. I'm also getting new brake shoes so I hope the "oversize" drums won't be an issue.

Mike

Place your new shoes in the drum and make sure there is a slight gap, (.010 or more), at each end of the shoe. If there is no gap on the ends check the center with a feeler gauge. If you can insert a feeler in the middle of the shoe it's radius is off and you'll need to taper the ends to make contact with the center. If you don't it will cause poor performance and can cause hot spots on your newly thin drum. If you can find someone that still archs shoes all the better but it's illegal to do in licensed shops. It's bad for the lungs.