A History of Aftermarket Birfield Development, by BigMike
In the early 1990s when Marlin invented the first Heavy Duty Birfield, aka the “Marfield”, it was designed to strengthen the body (shell/bell) of the original Toyota Birfield. Made right here at our shop, it was the very first upgraded Birfield, and in a world of 33″ tires, was thought to be unbreakable, so much so that Marlin put an ARB Air Locker up for ransom to the first person who could break his Marfield. This ransom only lasted one year, yet no one could deny how the Marfield paved the way for tremendous Birfield aftermarket growth.
By the end of the 1990s it was apparent that a joint better than stock was needed, and this is when a Birfield made entirely new from 4340 Chromoly was developed, aka the 4th generation “UM04” Marfield, plus a few newcomers introduced to the market during that time.
With the body of the Birfield stronger, the next point of failure became the inner cage. Knowing that the cage was failing before the inner axle shaft, a new design came to market in 2004 which featured a thicker and stronger cage through the use of a smaller diameter inner axle shaft.
This brilliant design had to overcome the issue of a reduced inner axle contact surface area, which it achieved by increasing the inner axle to Birfield engagement of 27-splines to 30-splines. This provided 11% more spline contact, and thus, the 30-spline Birfield and axle set was born!
The USA-made 30-spline Toyota axle set was a major improvement for the 1979-85 front live axle. Manufactured and tested by the family-owned and operated Illinois company RCV (rcvperformance.com) and sold through a single distributor in Washington state, the 30-spline Toyota axle set had become the leading choice for Toyota axle strength and dependability. From 2004 to 2012, other than an early ball bearing redesign from 5/8″ to 3/4″ diameter, the design of the 30-spline Toyota axle set stayed relatively the same.
Over the years we did offer these 30-spline axle kits here at Marlin Crawler and even ran them in our 3-time World Champion Formula Toyota Competition Rock Buggy. But the combined cost of shafts manufactured in Illinois shipped to Washington resold and shipped to us in California then resold again to our customers made our price on these shafts greater than market retail. Marlin Crawler has always wanted to offer RCV shafts but it was an economic impossibility most likely due to small production numbers of the Washington state storefront.
This all changed in 2014 when the retail side of these axles were returned to RCV. With the axle set now being both manufactured and distributed by RCV, we were able to pick the product line up for the first time. We have been selling these shafts locally at our shop in small quantities since 2014 and are now retailing them on our website!
Another great thing with the parts now being sold by the manufacture is that RCV could pour more of their proven technology into their original product without affecting the retail price. This technology came in the way of a vastly improved inner race material: 300M.
The new 300M-powered RCV 30-spline Toyota Axle Set is truly an amazing product. It is both 100% stronger than stock parts and 22% stronger than any other Toyota aftermarket axle set in the world. Period.
The new 300M inner race is like none other on the market. 300M is a Super Alloy, like 4340 on steroids, with added silicon, vanadium, carbon, and molybdenum. Compared to 4340, 300M has a higher yield strength, tensile strength, toughness, fatigue, and durability, precisely all of the characteristics desired in an axle shaft. And if this wasn’t enough, 300M responds better to Cryogenic treatment than 4340, making it more worthwhile to Cryo-freeze, which RCV performs, further increasing strength and hardness of these Birfield races only found in genuine RCV products.
As you’ve probably guessed this high quality material carries a high price tag. It in fact costs 5 times as much to manufacture a 300M Birfield race compared to a 4340 Birfield race. The good news is that RCV already uses 300M in other product lines, and the combination of their 300M manufacturing volume and direct retail sales has allowed RCV to maintain the same retail pricing. The rest as they say is history!
Please join us in supporting a fellow family-owned and operated company like RCV by running the world’s strongest genuine RCV Toyota axle shafts in your Toyota truck today!
Click here to view our 30-Spline RCV Axle Set Product Page!
