Since I had to do some research on the different "Budd caps" (inner wheel nuts) that are available on the market, in order to find the most suitable style for the rear of the M916-M920 trucks, I figured I should share my findings with the board.
This should be of interest to anyone that is putting singles with HEMTT wheels on the rear of these trucks.
As I mentioned above, the issue is the fact that the original wheel studs are to short for this conversion and the single style wheel nuts will not engage more then about 5/8 of am inch of thread. This is not acceptable and dangerous!
One option I have seen, is to just only use the extra long inner nuts (Budd caps) that are used with aluminum wheels. I personally do not like to use the "inners" by themselves. They have a very narrow tapered lip that is not intended to hold the wheel on without an outer wheel and a larger outer wheel nut against it.
This is why I use the system with the "blind" inner wheel as described in the previous thread. In addition it gives me a little extra track on the rear, making the difference between the rear axles and the front axle less pronounced.
It is very important though to use the 'Budd caps' that are best suited for this specific application.
Here are some pics of the different Budd caps that I have found:
-The shortest one on the left is a stock inner wheel nut as used on most dual steel wheel applications.
-The next one over to the right is an extended 'inner' that is only longer on the outside threads and is intended for applications where an inner steel wheel is combined with an outer aluminum wheel.
-Next to it is a 'inner' that is used with dual aluminum wheels but standard lengh inner threads.
-And finally, on the right is the one that I use and recommend for the HEMTT wheels. It has the extended length on the outside threads and it has FULL LENGTH TREADS on the inside, to catch as much of the factory wheel studs as possible.
One more thing: Any of the 'inners', that have the extra shoulder on the inside of the taper, can only be used with a 'blind' inner wheel plate that is 5/8" or thicker. If the plates are thinner then that, I recommend the use of the 'steel inner / aluminum outer' style 'Budd caps' (second from the left in the pic).
Soni
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