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My 1997 Firebird has the stock wheels and the stock rear lug studs. I installed the correct raybestos rear rotors and noticed less lug engagement. I checked the rotors and the hat section is 4mm THICKER than the stock rotor. With the new rotors I only have a little under 7mm of thread engagement holding the wheels on. Should be closer to 12mm for 12mm studs.
So I started looking at extended thread (ET) lug nuts. They have a bottom shank that adds 0.30" (7.6mm) of thread engagement. The problem is that section of the factory wheel is only about 6mm thick so it looks like the ET lugs will bottom on the rotor before clamping on the wheel.
Any idea how to solve this (I know longer studs is an option). I can't find rotors with a stated thickness any different than the raybestos. Thanks
I have a 1997 Firebird with the stock 16x8 painted wheel. I put aftermarket Raybestos brake rotors on the rear and since the hat section is thicker I lost about three threads of wheel stud/lugnuts engagement. YES, I know I can put longer studs in. Chose not to do that for now.
Everything I have read about the Extended Thread (ET) lugnuts says they will NOT fit in the hole of my stock wheels. The hole measures about 0.60 something and the specs for these ET lugnuts usually shows 0.62 and up. NO, I am not going to drill my wheels as others have to use ET lugnuts.
Just for the hell of it I took a chance on a set of 12x1.5 chrome open end lugnuts on Amazon. They did NOT give a OD spec for the shank. I was pretty sure that when they arrived they wouldn't fit. They arrived. THEY FIT! They measure just over 0.60" and fit in the hole loose enough to assure lug centering.
Here are ET lugnuts that fit our stock wheels. I am not advocating the use of ET lugnuts just offering the option if you have decided it is right for your car. I wound up having the thinner hat original rear rotors turned and I'm using the factory lugnuts and covers but will keep these for that rainy day. Go the FLYCLE store on Amazon and look at their lugnuts and you will find them. Chrome or Black.
Last edited by rkjjeep; Mar 6, 2025 at 08:23 AM.
Reason: spelling
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Extended thread lugnuts question 
