Basic Wheel Bolt Information:
- Stock Bugeye lug bolt length = 1 1/2" with original front drum brakes
- Stock Bugeye lug nuts are conical/tapered/cone shaped
- Minator chrome wheel nuts = 3/8' - 24 with 1 3/16" threaded closed end nut
Why do I need to measure my lug bolts with non-stock (aftermarket) wheels?
Unless specifically mentioned from the manufacturer that OEM wheel bolts can be used with your after-market wheel, it’s
important to always re-measure the lug bolt length. Some aftermarket wheels will have a thicker mounting pad (surface of the wheel that mounts against the hub of the vehicle). If that is the case, the stock wheel studs may be too short for the threads to pull properly. You need at least 9-10 engaged threads, (minimum).
Another "Rule of Thumb" to calculate thread engagement is to multiply the lug's threaded diameter by 1.5. For example:
3/8" x 1.5 = 9/16" length of engagement
9/16" x 24 TPI = 13.5 threads
In my case, after measuring the stock lug's exposed threads, extending through the hub/drum, and subtracting the wheel mounting pad, I had 9/16" of engaged threads. Still, that seemed to be on the "light" side of things to be safe with the 5' x 13' Minator wheel and 175 x 70 13 tire combination.
Extended Wheel Lugs and Verifying Engagement
This is an excerpt from the MG-Cars.info forum:
"The minimum required length of thread engagement is dependent on the relative strength of the male and female thread components and whilst the stud is usually good, unfortunately the same cannot be said for the nuts where it is possible that a much reduced strength of material has been used. In the limit, the bolted connection should should fail by tension in the stud and not thread stripping in either component. A further allowance should also be made in respect of thread wear that is far more likely to occur in wheel bolting than any other connection on the vehicle due to their more repeated use however caution must be used as thread lubricants may significantly reduce friction to result in failure due to excessive loading even at the stipulated tightening torque value. Better to only lightly oil threads and to replace, primarily the nuts, every few years or around 10/12 torque tightening operations."
"Scarlet's" Specific Wheel/Bolt Information:
Extended Wheel Stud length = 3/8-24 UNF x 2" (50mm)
Minator chrome wheel nuts = 3/8' - 24 with 1 3/16" threaded closed end nut
Minator 5' x 13" Spoke Alloy
The Minator Alloy wheel is based on the design made popular in the USA by Panasport. My Minator version is made by "KN" in the UK.
After ALL of my measuring and test-fitting, I still wanted to be sure that the lug was not bottoming out on the closed-ended acorn nut and that the nut was fully seated into the Minator wheel. My solution was to coat the cone-shaped base of the Minator lug nut with paint from a Sharpie paint pen. I then mounted the wheel to the hub/drum/wheel combination and properly torqued all of the nuts to 46 ft. lbs. (per factory specs ). As noted in the pictures above, when I removed the painted nut, all of the paint had been scraped/transferred to the base of the wheel. * Some vendors recommend 38 ft. lbs. for Minator wheels.
Conclusion: The Minator wheel, lug nut and front drum brake combination works fine with an Extended Wheel Stud length = 3/8-24 UNF x 2" (50mm)
Sprite & Midget Tire Sizing and Wheel Selection
DIY: How to Calculate Lug Stud Length