With larger tires and more horse power than ever before being used on the trails these days, upgrades for your rig are more critical than ever. In a Toyota, one of the common failures are your stock 27 spline birfields. That is why we have developed our new 30 spline chromoly birfields, the Dirty 30s' ™. This birfield will get you to where you need to go and give you confidence and peace of mind while you are getting there.These Dirty 30’s are made out of 100% 4340 chromoly and are precision polished to remove any imperfections that may cause stress risers. The ball bearings are manufactured out of the highest quality attainable in chrome steel ball bearing manufacturing, AISI 52100 is the standard of material used. The 30 spline axle shafts are 100% chromoly with a polished seal surface. These parts have undergone years of extensive in-house and field testing and we are proud to share the results with you. The average failure rate was consistently at 8500 ft. lbs. of applied torque at a 30 degree angle. They were also field tested at the Hammers in our competition FToy and other buggies and trucks with no failures to report. In fact, we feel so confident about the quality of these Dirty 30’s that we are offering them with a no questions asked lifetime warranty.Note: Some minor clearancing of the knuckle ball may be required