Sonoma Raceway crash - turn 4

[hobbes3]

Tzrider, that is a well informed and well thought out explanation. Thank you very much! I learned a lot reading your post.

I'll be re-reading your post a few times to make sure I soaked all of the info.

[hobbes3]

As a bonus, here's the bike before, naked, and after:





A lot of my friends on Facebook like the white version more :-).

[EastBayDave]

Originally Posted by hobbes3

As a bonus, here's the bike before, naked, and after: A lot of my friends on Facebook like the white version more :-).

Ok, now get some new crash bars on there (case savers? Ya'all know what I mean...it's early zzz) to protect that clean bodywork...

Get back on & RIDE!

[FXCLM5]

I crashed 4 and 6 both downhill turns.

How is your bp? Are you dragging knee and off bike?

[Nick]

Originally Posted by thedub

Underloaded front tire, just like every other track day crash on the front. You were on the gas a country mile too soon.

+1

I took a screenshot of where you started adding throttle in the video (see below). That's like 50+ feet before you should be on the throttle. The rider that passed you isn't even past the apex yet in the screenshot.

Tim Scarrott (former AFM racer) has maps of all the AFM tracks with lines and detailed notes hosted on his website that I have found helpful over the years.

Sonoma Raceway
Thunderhill Raceway
BUttonwillow Raceway

[hobbes3]

Originally Posted by FXCLM5

I crashed 4 and 6 both downhill turns.

How is your bp? Are you dragging knee and off bike?

I'm definitely still learning a lot about body positioning. Ironically I got my knee down for the first time that day before lunch. I got it down very shortly for like 1-2 seconds on turn 6, the carousel, but I got it down consistently on that turn that day.

Originally Posted by Nick

+1

I took a screenshot of where you started adding throttle in the video (see below). That's like 50+ feet before you should be on the throttle. The rider that passed you isn't even past the apex yet in the screenshot.

Tim Scarrott (former AFM racer) has maps of all the AFM tracks with lines and detailed notes hosted on his website that I have found helpful over the years.

Nice! Thanks for those links. I've seen them before but never had a chance to review it on my computer.

As for adding throttle, I'm a bit confused. I know people say when you trail brake you don't add throttle until you get past the apex, people also say to add slight acceleration throughout the turn. I assume that during trail braking releasing the brakes slowly toward the apex increases acceleration too?

When I was adding throttle there, I was definitely adding minor acceleration. In fact, I have a bad habit of not cranking it open right before the straights.

Basically, I'm asking if I wasn't adding more lean during the turn then it would have been correct to continue with the acceleration like I was doing in the video, right?

[stangmx13]

Originally Posted by hobbes3

I'm definitely still learning a lot about body positioning. Ironically I got my knee down for the first time that day before lunch. I got it down very shortly for like 1-2 seconds on turn 6, the carousel, but I got it down consistently on that turn that day.



Nice! Thanks for those links. I've seen them before but never had a chance to review it on my computer.

As for adding throttle, I'm a bit confused. I know people say when you trail brake you don't add throttle until you get past the apex, people also say to add slight acceleration throughout the turn. I assume that during trail braking releasing the brakes slowly toward the apex increases acceleration too?

When I was adding throttle there, I was definitely adding minor acceleration. In fact, I have a bad habit of not cranking it open right before the straights.

Basically, I'm asking if I wasn't adding more lean during the turn then it would have been correct to continue with the acceleration like I was doing in the video, right?

if u hadnt added extra lean, it would have been reasonably safe to add minor acceleration like u did. but you are confusing track and street techniques. taking the turn that way is horribly slow and becomes risky as u try to go faster. so save that for the street.

all this is a matter of where the slowest point of the corner is. on the street, the slowest point is very early in the turn or even b4 the turn because u get most of your braking done right away. the braking is ez because its all upright and the acceleration must be very slow so u can finish the corner. on the track, the slowest point is at or very near the center of the turn. the braking is difficult because u brake with lean and the acceleration can be hard since u are already pointed at the exit. in both cases we brake all the way to the slowest point and we accelerate away from it, but the difficulties and magnitudes are way diff.

does that all make sense? i could prob find u some diagrams if necessary.

[tzrider]

Originally Posted by stangmx13

all this is a matter of where the apex is, where the slowest point of the corner is.

I'm not familiar with this as a definition of the word apex. When describing a line, the definition I'm familiar with is the place where you are closest to the inside edge of the track. That may or may not be the slowest portion of the turn, depending on how you approach it. If trail braking to the apex, yes; if getting off the brakes at the turn entry and flicking the bike in, no.

You and I do agree that the risky combo in this instance was adding throttle and lean angle at the same time.

[stangmx13]

Originally Posted by tzrider

I'm not familiar with this as a definition of the word apex. When describing a line, the definition I'm familiar with is the place where you are closest to the inside edge of the track. That may or may not be the slowest portion of the turn, depending on how you approach it. If trail braking to the apex, yes; if getting off the brakes at the turn entry and flicking the bike in, no.

You and I do agree that the risky combo in this instance was adding throttle and lean angle at the same time.

ya i guess thats not standard convention. ill reword it to not confuse ppl.

ive been racing more MotoAmerica this year. i still havent found a corner where ppl get off the brakes at entry and flick the bike in

[jmann]

Just curious. Would one of the more advanced bike with traction, slide control, etc.... have helped and possibily saved this crash?

[Smash Allen]

Originally Posted by jmann

Just curious. Would one of the more advanced bike with traction, slide control, etc.... have helped and possibily saved this crash?

I don't see how in this situation, dude did this in front of me on a 2015 R1. There was no slip to control or even enough throttle for precontrol. Perhaps if in rain mode it would have smoothed out his throttle application which would have kept more weight on the front.

[afm199]

Originally Posted by jmann

Just curious. Would one of the more advanced bike with traction, slide control, etc.... have helped and possibily saved this crash?

Yes and no. If the traction control on the bike was set to "rain", or most interruption, it might have. The crash was caused by the rider adding throttle and lean angle. The convention is to remove lean angle and add throttle. He simply got on the gas way to early in the corner, while still entering and way before the apex. That's why he crashed. The rider in front of him carried much more speed and braked all the way to the apex, the correct way to do it.

So if the traction control was set to a much higher level, it might have. However at that level, the available power would have been so limited that it would have been a small fraction of what was possible. In other words, the bike would simply have no power on exits.

[stunna]

Originally Posted by Smash Allen

To me it looks like you were adding lean angle and throttle at the same time, most likely as a response from being passed shortly before. To prevent this in the future I would recommend to get the bike pointed before adding throttle, and never add throttle and lean angle at the same time.

You and the bike okay?

+1

[r6rammy]

Originally Posted by afm199

Yes and no. If the traction control on the bike was set to "rain", or most interruption, it might have. The crash was caused by the rider adding throttle and lean angle. The convention is to remove lean angle and add throttle. He simply got on the gas way to early in the corner, while still entering and way before the apex. That's why he crashed. The rider in front of him carried much more speed and braked all the way to the apex, the correct way to do it.

So if the traction control was set to a much higher level, it might have. However at that level, the available power would have been so limited that it would have been a small fraction of what was possible. In other words, the bike would simply have no power on exits.

Does traction control even work for front wheel traction?

I've been guilty (still am) for over slowing the entry and trying to compensate by adding throttle way before the apex (T9 at Thill). I now know that its best to throw away that corner and fix it on the next time at the same spot, by not over slowing the entry. If you trailed brakes (keep front loaded), then losing traction at front is a factor of lean angle and speeds mostly (this is where BP comes in, to some extent). The limits of that traction, I dont want to find out

Glad you and bike are OK and you used this as a good learning experience.

[afm199]

Originally Posted by r6rammy

Does traction control even work for front wheel traction?

I've been guilty (still am) for over slowing the entry and trying to compensate by adding throttle way before the apex (T9 at Thill). I now know that its best to throw away that corner and fix it on the next time at the same spot, by not over slowing the entry. If you trailed brakes (keep front loaded), then losing traction at front is a factor of lean angle and speeds mostly (this is where BP comes in, to some extent). The limits of that traction, I dont want to find out

Glad you and bike are OK and you used this as a good learning experience.

That crash wasn't due to a front tucking first, it was due to a rear spinning up, losing traction, and stepping out, which created enough more lean to tuck the front. I've done it more than once.