Lowside at Sonoma Supermoto Track

[sckego]

Pretty straightforward crash, but interesting circumstances that led to it, so might as well share...

Saturday afternoon practice for SupermotoUSA races, on my WR250X-SM (street tires, no warmers). This race weekend had two different track layouts: one all asphalt, and one mainly asphalt with a dirt section with a few jumps. Different classes ran one layout or the other, depending. Practice schedule was Asphalt (Fast group, then slow group), Dirt (fast, then slow), Asphalt, etc...

I was planning one running one race of each, but was pretty nervous in the dirt section, so I would do the fast asphalt group, then the slow dirt group. The first couple of corners after exiting the dirt section were also super slippery due to tires being dirty, and I was not used to that at all (another reason I stuck with the slow dirt group). I had just finished the slow dirt session, paused in the pit lane for a minute, and headed back out with the fast asphalt group.

First lap out, I'm coming through a tight ~130deg left-hander doing 30mph-ish, knee out, full lean. The exit of this particular corner is where the dirt section rejoins the asphalt. This rather important fact was somehow not in my head at all as I started to add throttle after passing the apex. As I tracked out towards corner exit, I got onto the dirty line left from the previous dirt session, and lost the rear instantly. I don’t recall any warning, or having time to respond at all, just BAM on the ground. My left elbow was still out in cornering position and hit the ground first, followed shortly by the rest of me, and I slid to a stop pretty quickly.

So, analysis. Not sure what I could have done once the slide was initiated - a better rider could have probably saved it, but it just happened too fast for me to react. I think my major error was just a complete mental brainfart, not even considering that this was where the dirt section joined back in, and that this nice clean corner would suddenly be very not clean any more. In previous sessions I had come in for a few minutes before heading back out with the fast asphalt group, and I think the couple of laps those guys did would clean up the line a bit before I went back out. I would also be a bit slower on that first lap since my tires would cool down and I’d need to warm them back up. This was the first time I headed straight back out on the first lap after the dirt sessions, with still-warm tires, hitting that corner at pace while it was still really dirty.

I got up and ran over to the bike, intending to pick it back up and keep going, when I realized something wasn’t quite right with my left shoulder. Turns out I’d dislocated it, and the very helpful staff at Sonoma Valley Hospital helped get it back into place later that evening… though I missed the races on Sunday, and am also going to sit out AFM R7 this coming weekend. Ah well, see you guys back out there next season!


Dirt track running parallel to asphalt, rejoining at the exit of the asphalt corner - I came through along the green line and crashed at the X:

[budman]

Sux man.... your analysis seem right to me.

Heal quick.

[APpy]

Your chances of saving a slide get exponentially higher if you ride foot out. At least for me it does.. there's a reason dirt riders sit on the tank and push the bike under. Rear wheel slides are a complete non-issue. Even when the front pushes, it does't push as far since you are on top the front wheel and your weight will stop it.

I'm faster riding road race style if traction is perfect. But this weekend, several riders (incl. me) switched to foot out. The only place where knee down felt good to me were the 2 turns getting on and off the front straight. Both higher speed and pretty far from the dirt section.

[thedub]

Doesn't seem like there is much left to analyze...

Bummer about your shoulder.

[doc4216]

Sorry to hear about your shoulder. Speedy recovery!

[supermotomax]

Pretty thorough and helpful analysis here. Sorry about your shoulder, and I hope you can ride again quickly!

[kiwifornian]

Make sure you do your rotator cuff strengthening exercises.

The first dislocation is an anomaly.

The second dislocation is a pattern.

[Kantoh]

So, you skipped a sighting lap then" Maybe that's the root cause here?

[Kestrel]

Originally Posted by APpy

Your chances of saving a slide get exponentially higher if you ride foot out. At least for me it does.. there's a reason dirt riders sit on the tank and push the bike under. Rear wheel slides are a complete non-issue. Even when the front pushes, it does't push as far since you are on top the front wheel and your weight will stop it.

I'm faster riding road race style if traction is perfect. But this weekend, several riders (incl. me) switched to foot out. The only place where knee down felt good to me were the 2 turns getting on and off the front straight. Both higher speed and pretty far from the dirt section.

The caveat with foot out being... I've seen some absolutely destroyed knees when foot out leads to sudden traction and contact with the ground. That's a lot of energy your human skeleton was simply not designed for. Beware. You see a lot of off road riders with jacked knees, too, for just that reason. That said, my supermoto riding is a mixture of foot out and knee out. Depends on the track, and often I do both depending on what the situation calls for.

Having essentially learned to ride while living in Wisconsin, dirt/gravel in the corners is a pretty routine thing. No nice grass shoulders like NC and the like, so the roads can get a bit dirty out in rural parts. An errant stone or small splotch of dirt isn't enough to result in a total loss of traction; the rear end would step out an inch, and you'd go about your business.... especially at speed, when the inertia of the rotating wheel helps keep the bike upright.

Long dirt patch with slow speed and any decent lean angle? Yea, you're in for trouble. Beware!

[mark665]

In low-traction areas, foot-out can really help, with all the caveats above.

I'll typically ride kee-out when the track is clean/a-only races, and switch to foot-out when there's a potential traction concern.

The other thing to do is be more aware of the changing track surface and alter your line appropriately to be more up-and-down over the lower-traction area.