The Ultra4 trend these days seems to be “go big or go home”. Granted, if you want to be on top there’s a fine line of making things just strong enough, it’s this that separates basic design from solid engineering. In the case of IFS outer stub shafts however, moving over to 40 spline just makes good sense.

First, we work with the same billet material as 35 spline IFS stubs, so there’s no cost difference in manufacturing. That’s a big win, but it gets better still. While outer IFS stub shaft failures are near non-existent, as we continue to push the boundaries of Ultra4 racing, increasing the stub shaft diameter will likely become necessary. Since we already manufacture  Ultimate Unit Bearings in 40 spline, making IFS 40 spline outer stub shafts was an obvious fit.

So there you have it. Spidertrax 40 Splined 300M Billet Series 30 Outer Stub Shafts are available on our online store, in-stock as of this post.