The Trigo instructions state that the threaded stud should only protude 5/8" (.625) from the face of the adapter, the adapter is 3/8" (.375) thick. This means the stud is to be 1.0" from the brake rotor face. If this dimension is dismissed and not taken into account, the internal hex or star tool will be progresively (and perhaps unkowingly) pushed out as the nut is being tightened down on the stud, causing a minimal length of the tool to be engaged at the exact time the most torque is being applied. Then if care is not taken to keep the tool correctly engaged (IE: torque wrench cocked to one side using one hand) the twisting force can be applied and spread open the end of the nut as some have experienced. So a word to the wise...it may be necessary to remove the studs and ultimately have their legnth reduced and then be reinstalled. This is a very important step. With the .750 diameter tapered nuts installed and securing the adapter, the diameter of the holes in the wheel are 49/64ths (.765) leaving a .015 clearance. The holes in the wheel are a little over (unmeasured at this point) 1.000" deep.
Those with a keen eye will notice these adapters use 6 in lieu of 5 threaded studs and Trigo nuts on a 4.25 bolt circle. I had my heart set on putting FIA wheels on a Ford 9" rear end. These wheels require a 6 pin pattern because of the mounting pad on the OEM style FIA wheels. Trigo had yet to bring their own FIA wheel to market that was patterned to use a common 5 pin adapter. I purchased the adapters blank from Trigo and machined my own 6 hole pattern (4.25" diameter) and had the new axles machined for the same pattern.
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