The new Toyota GR Corolla has a problem. The stock wheel studs are too short when running aftermarket wheels with a conical seat.
there’s some debate on “proper lug engagement”, but there is a minimum. My argument is for full diameter of the bolt is proper engagement. For an m12x1.5 bolt that’s 8 full turns. Minimum for an m12x1.5 bolt is 6.5 turns which is about 80% of the bolt diameter.
Many racing series require the wheel stud to stick out of the lug nut. This guarantees full engagement and is easily checked in tech.
Alright down to the details.
Stock Front has 27.7mm of threads and is 41.2mm seated length
H&R 35mm (comes with their 5mm spacer kit) has 36mm of threads and is 47.2mm seated length
Stock Rear has 35.7mm of threads and is 48.85mm seated length
H&R 40mm (comes with their 10mm spacer kit) has 40.6mm of threads and is 51.9mm seated length
H&R 50mm (1255044) has 50mm of threads and a 61mm seated length
ARP 100-7715 has 54mm of threads and is 66mm seated length
Seated length is the important number since the lower threads cannot be used.
Running the H&R 35mm front and 40mm rear will give you enough engagement. This also means you could move your rear studs to the front and run a 40mm rear stud.
I'm working on getting my hands on some 55mm Ichiba wheel studs as well to confirm they work as I believe they will.
More to come as we add more options to the website and do more testing.
-Drew Penguin Garage
*Updated 8/14 to include newly tested H&R 1255044 which is 50mm of thread. Updated image and content to reflect H&R thread length as their identifier to avoid confusion.