Help diagnose rear wheel low-side at PittRace 8/28?

[JR711]

I know it's tough to tell exactly what is happening from on on-board view but as best I can tell I used too much exit throttle too soon. Lean angle was too much and I probably hammered on instead of rolling on. I was riding I group last Sunday. I think I took this turn for granted and never really felt like I needed to lean much but as speeds come up I need to be smoother on my inputs. Ironically I just read the 100 points of grip article someone posted in this forum two days before this. Slow learner I guess.

 

[Otto Man]

Seen a lot of people crash there. You didn't hammer the throttle on, but you did do exactly the opposite of what YCRS teaches. The most important piece is what you did leading up to the turn. You were rolling on the throttle, while adding lean angle. You were at the most amount of throttle application at the apex of the corner. You added lean angle points and added throttle points to the rear tire. You'll find the pointy end of the A group guys are actually braking where you were adding throttle, pre-apex. After making that right, you upright the bike and drive it hard up the hill, and you're actually adding a touch (admittedly not much) trail brake to get the front end settled for that turn.

 

[adotjdot]

Yep, I'd have to agree 100% with what Otto Man said. Adding throttle and lean angle into the turn. Remember, any type of direction change, the bike needs to slow down. Typically that means using the brake or baking off of the throttle to transfer weight to the front wheel. Every corner is different and the variables such as speed, direction, your place in the corner, all contribute to what control you need to use and to what degree. If you are only backing off the throttle without needing the brake then what do you think that means? You can go faster into that corner! Because you have a control (brakes) to help you slow down to make that direction change.

 

[YZROOSTINYA]

Similar to above.

There is a bump there. I'm on the gas there before and after the bump and somewhat neutral through it. Good tires(2 years or newer) and at least stock suspension sorted(preload minimum) would of helped minimize this. If you already have this done I would focus on what you are actually doing as you enter the turn(on the gas, neutral , or braking ), mid corner, and exit.

If you had all of this info you would be able to tell me I was on the gas and I felt the front get light then the rear stepped out. For example.

There are 20 things that could have been done to fix the problem. The most important thing is understanding what you did when it happened. I hope this makes sense.

John

 

[mpusch]

Hehe, not that any crash is fun, but be glad that rear tire kept going and didn't catch. I crashed in that exact spot in July, but ended up high siding myself to the moon. Good times, have the pins in my wrist to prove it.

I totally had the same mindset as you, always took that corner for granted. Don't think I did anything terribly bad (same as you) but will be paying a bit more attention there now. There is definitely some kind of bump or depression there, because we definitely aren't the first to have that happen to us.

 

[rhill]

got a real time clip?

To echo what has already been said...that corner has bitten more than a few riders.
Accelerating up the hill requires some aggressive throttle....if that isn't backed off as lean angle is added, you are demanding a lot from the tire.
Now add in a slight crest as the track levels out AND the little bumps through there....you have the result.

I've had a few moments there running the North track alone....coldish tires on the first demanding left will really wake you up at the start of a session. With the 750, I short shift up the hill and back off to "maintenance throttle" or very close while passing the apex, then have a fairly aggressive roll-on as the bumps are passed. And speaking of apex, because it is in the middle of a right-left-right....if you are 2 feet off the curb there, you have a lot more turn to make...meaning more lean angle at the same speed.

Also, watch that curbing...some spots are not forgiving.


edit.....my first thought was "hope you and the bike are alright" and I forgot to type it out

 

[JR711]

Wow, thanks for all of the responses. Great feedback and quite an education on that piece of track as well as breaking down turns in general. The experience in this group is invaluable. I read and re-read everything related to technique I can get my hands on but nothing replaces awareness, feedback and laps. Looking forward to an ATP day next season.
@mpusch I remember thinking, "I sure hope this rear tire doesn't stand up on me" right before I let go!

Bike was fine, I'll be replacing some pegs and a cover on that side, have some repairs to make on my suit but everything did exactly what it was designed to do in terms of safety. Thanks for asking and thanks again to the group.

 

[HavocCat]

Thank you for posting! This is a great learning point for everyone. At your expense though, which I am sorry for.

Glad you and the bike are alright, you are definitely not the only one who crashed here over the weekend.