To first understand wheel studs, let's look at the technical details behind them. The ARP studs are made from 8740 chrome moly and are cadmium plated, this results in a maximum tensile strength of 200,000psi. This would be the equivalent of applying 112ftlbs of torque to a regular Toyota passenger car 12mmx1.5 stud. The original Toyota 8T studs torque spec is 76ftlbs, but there is no data on their maximum tensile strength. So without using an oscilloscope and torque gauge to test each stud we can't definitively say witch studs are stronger. I will report that many people have lost a wheel or noticed their OEM studs cracked or broken after track racing. I've never heard one bad report of any ARP hardware, and I believe they are essential for those of us removing and installing wheels often.
I had originally purchased these studs for their length back when I had the JDM Vitz rear disc brake conversion. I had a set of 15x7 RPF1's and the rear caliper did not clear the wheel drum taper, so I used these longer studs and 10mm spacers to make it fit. ARP does not make a kit specifically for the Yaris so I had to do a bit of research to find the right size Knurl, luckily all I needed to do was measure and compare on ARP's website. The Lexus IS300 wheel stud kit was a direct match, they come in packs of 5, so you need to order 4 packs even though the Yaris hubs are 4x100. You can order these HERE.
Installation is relatively simple but you will need a wheel stud installer and open-ended lug-nuts. Once the brakes are removed, the original front studs can be hammered out and the new studs installed from the forward side of the hub. However, the rear hubs will need to be removed due to insufficient clearance of the backplate. During instalation be sure to apply some synthetic grease to the threads, this will ease in installation and protect the stud from any corrosion in the future. You can get the grease HERE, and the installer HERE.
The final piece of this fail-proof upgrade is a proper lug-nut. I've been around cars and racing a long time, and I've seen people use a lot of different lug-nuts. So please listen when I say to avoid the aluminum nuts. Yes they are lighter, but they also expand at a different rate of the stud and strip after several on-off cycles. Remember to apply some grease to the stud, use a steel lug-nut, and torque to spec. I really like the Gorilla forged lug-nuts, they are heavy duty, have a knurled end for easy installation, and are open-ended. You can purchase the forged lugs HERE.
Maintenance is easy, all you need to do is clean the threads, inspect for wear, and apply new grease. I've had this set-up on my car for 3 years now, and I've never had any issues. I rotate the tires after every race and at lunchtime during track events. Hundreds of on-off cycles and 4 different wheel set-ups, you could safely say I've tested them thoroughly.
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