Speaking to the guys that race or pound the whoops regularly: Are any of you adding knuckle studs and/or increasing the size? Is it necessary? Although the spindles are hub centric, it certainly seems the studs are a bit undersized for heavy pounding. I've heard of spindles tearing off when running 37" tires, so it seems they would be on the edge with 35's.

Kevin Mcqilvry has 18" front and rear wheel travel with over 500hp in his prerunner with Goodyear 37's and his studs are stock. I have pre run with him many times and the truck runs 50-60 all day across the desert floor.The ball joints last about 750 to 1000 miles though. Kevin is a past Protruck racer now campaining a Trophy truck. This is the same Bronco that Casey Folks (the BITD promoter) rides in to do all the BITD preruns. He has not torn out any studs.

I've never had a problem with them so I've never had any reason to go larger or add studs. If I was going to strengthen this area though, I think adding another six studs would be better than increasing the diameter of the studs.

Something to keep in mind is that the main purpose of those studs is to hold the snout to the steering knuckle (you already know this) and the only time they are under a huge strain is when the truck is at full bump and the tires have a fair amount of negative camber. In this situation, camber and compression loads are trying to pull the wheel and anything attached to it off the truck. This is why beamed trucks with excessive bump travel typically have more issues than beamed trucks with excessive droop travel.

Paul or Chris Wilson could probably provide good first-hand information on the subject. I'm sure both of them are either in or prepping for Baja at this point, though, so it'll be a while before you could get info out of them.

BTW: I think the cast steering knuckle would fail before the studs.

when i did mine on the SAS it was too much of a PITA to get studs... the ones i ordered showed up wrong... i thnk they are 3/8 or 7/16... mine are now all 1/2" because i just used grade 8 bolts

dc