[cscobra]

My "old" 1952 MG TD and my current 1957 MGA both use finely splined hubs and relatively fine threads (12 per inch) on the knock-offs themselves. I use a lead hammer to check each "spinner" before and after every run and have never experienced any loosening.

Regarding my ERA 427 Cobra, I "indexed" my wheels to their best fit on the "pegs" (so five or six positions must be tried, depending upon the chosen type) to ensure that the wheel is truly flush with the hub. There is usually only one best fit from all of the positions. If this is not done, then the knock-off will never be tight enough (and will need to be continually tightened), handling will have "variations," and unusual tire wear will ensue. Once you find the best position, always keep the wheel in that same position relative to its hub.

If the indexing is done correctly, then no problems should occur. I use the same lead hammer previously mentioned to check each "Cobra spinner" before and after each run (longest run: 400 miles, with another check at a gas stop; total mileage now 1100 after one year post completion), and I have yet to experience any loosening of the knock-offs. I recently received the R-clips from Vintage Wheels (the manufacturer of my wheels) and I will add them just to be complete, but I choose to not mar my wheels with "safety wire" when I've had no problems for nearly 30 years with this type of wheel retention system. Any driver of these cars likely has the skillset necessary to recognize a knock-off coming loose and should have time to slow to a stop before the R-clip can wear through (which it probably would, given enough time to generate enough heat).

Bottom line: use the lead hammer regularly and consistently, and make sure that your wheels are properly indexed to their respective hubs.