Yes they are for rimlocks.
back in the day the tyre pressure was a lot lower than used in tyres now days.
When I first got mine I ran 14 & 16 psi which was not enough to keep the tyre on the rim.
Eventually I tried higher pressures and now run 20 & 25.
Previously I would spin a case enough to rip a valve at least 2 or 3 times a year.
What thought adverse handleing due to high tyre pressure engine up being loose bolts and a cracked mounting plate.
