The Gen4 KTM Superduke Handling Mystery: Why It Steers Slow (And What The Numbers Actually Say)

If you own a Gen4 KTM 1390 Superduke, there is a good chance you've noticed something a little off about the handling.

I know this because my inbox looks exactly the same today as it did when the Gen3 was released. The emails I get from Gen4 owners are practically identical: everyone is complaining about the bike steering lazy, feeling sluggish on turn-in, and generally not delivering that razor-sharp response we expect.

Recently, a customer reached out who had purchased a +15 link for his Gen3 and wanted to know if it would fit his new Gen4, especially since he'd read online that the rake and trail were completely different.

The short answer? Yes, the parts fit. The swingarm, links, control arm, and shock length are all exactly the same.

But the long answer? That requires diving into the actual chassis numbers, and what I found completely explains why the Gen4 feels the way it does.

The 101mm Trail Myth

KTM's marketing materials state that the Gen4 has 101mm of trail. But judging by the emails I'm getting, and my own data logging around the racetracks out here in California, there was no way in hell that number was accurate.

To get to the bottom of it, I packed up my Gen4 last month and drove four hours to put it on Gerry Piazza's $80,000 digital arm chassis measuring machine.

If you want to know the truth about a bike's geometry, you have to measure it the way precision builders do: with the suspension hanging, absolutely zero weight on the tires, and the shock and forks topped out. When we measured the Gen4 this way, the marketing claims fell apart.

My Gen4 measured 103mm of trail. Keep in mind, that measurement was taken with racing slicks mounted, which are 8mm taller than the stock tires. If you run the math backward for the stock rubber, the Gen4 actually sits at 104mm of trail.

Suddenly, all those emails complaining about lazy steering make perfect sense.

Track Proven: Gen3 vs. Gen4

I already knew the Gen4 was steering slow because I've been riding it back-to-back with my Gen3. I've compared them going into turns, mid-corner, and driving out.

Right now, my Gen3 absolutely destroys my Gen4 everywhere on the track.

I'm talking 8 seconds per lap quicker. I'm averaging 10mph faster at full lean, and in some of the faster sweeping corners, the Gen3 is carrying a massive 15mph more corner speed. The geometry simply allows the older chassis to out-turn and out-handle the new one in its stock configuration.

The Solution

The good news is that we can fix it. Because the linkage components carry over, you can correct the Gen4's geometry using the exact same principles we used to dial in the Gen3.

Whether you're transferring parts over from a Gen3 or looking to sharpen up your new Gen4, the only difference you need to acknowledge is which model you own. If you have the standard R, the standard Sportlink just bolts right on. If you have the Gen4 EVO with the electronic suspension, you'll need the EC version of the Sportlink (left side only).

And if you're looking to dial in your front end at the same time, the Superclamp pairs perfectly with the Sportlink for a complete geometry correction.

Bolt it on, correct that trail, and go have fun.