Turning is Braking

[Roberts]

I know this is probably not a revelation to most racers, but it certainly was/is to me.

The 'no brake' drills are a pretty good hint, as are the stories told by Keith about dead-motor downhill canyon racing.

My 'lights on' moment came when following my coach through a corner on the track at speeds that were far above my comfort level...I honestly though he was making a mistake...and coming out the other side so slow I needed to tap a handful of throttle just to catch back up.

I credit this fact with my other major problem..adding throttle while adding lean...because my entry speed was far too slow, my turn too aggressive for that slow speed, and the dramatic loss of velocity due to hard turning *required* more throttle just to reduce the rapid decline in speed.

This is very hard to practice on the street, where corners are designed for steady and even traveling speeds.  There are very few civilian corners where you can come in hot and drop significant speed by hard turning.  This, to me, is a very important thing to understand and apply.

If this is on the right track, here's my question:  How much speed do you expect to shed in turns on a track?  I know every corner is different, but in general terms, are you looking to lose 25%?  45%?  Are you basing your entry speed and turn in point on the expected loss of speed due to aggressive turning?

 

 

 

[El Colibri]

Great realization and good questions:

The only answer I (personally) can give is, absolutely my entry speed and turn point take into account the anticipated  loss of speed from TP to max lean. 
 

Translating this fact into a percentage isn’t necessarily impossible, but would need to make numerous assumptions (i.e. sharp 90 deg on flat surface vs 90 deg turn with 100 ft radius going uphill). 
 

Compounding the difficulty in making a percentage translation are the engine braking characteristics of the bike or particular ECU map (e.g. Sport vs Race mode). Engine braking could very well be a greater factor in deceleration than the force generated by an aggressive turn by itself (assuming 0% throttle and 0 brake from TP to max lean). 
 

There’s a process of working a turn backwards that Keith addresses in Twist I (if I recall correctly).

[Lnewqban]

19 hours ago, Roberts said:

...My 'lights on' moment came when following my coach through a corner on the track at speeds that were far above my comfort level...I honestly though he was making a mistake...and coming out the other side so slow I needed to tap a handful of throttle just to catch back up.

Why did your coach use less time than you to complete that curve?

Did you both use the same turning point?

Was your entry speed comparable to his?

If so, did you let your bike slowdown (before cracking the throttle open) longer than he did?

What do you call hard turning?

[Roberts]

Great questions.

I was working hard at being a good copycat.  I didn't brake at all, and I stuck to his fender and turned where he did.  He was super-smooth and got the work done with speed and grace.  I assume I was  not as graceful, and I was probably off the throttle too soon, and not on again fast enough, because I was having some emotions at the time.  As stated, I thought this was a mistake..but it was brilliant.

Hard turning.  I ski.  To go down a steep face, you turn hard and often to keep your speed in check.  Miss a few turns, and you have to slalom, fail to dig in, and you become a passenger.

When I refer to 'hard turning' I am talking specifically about turning with the intent of using the conservation of angular momentum to convert velocity into a change in direction and reduction in speed.  I wish I had talked more with my coach about the decades I spent racing offroad.  One of the most common turns in the woods is jamming your bike into a berm or a ditch or a rootball, to shed speed and redirect yourself at a sharp angle to your incoming direction.  Like a jump-turn in skiing.

On the pavement of a racetrack, the best equivalent is getting all the physics right to lean in hard enough and fast enough that your suspension loads evenly and firmly, and you can feel the tires bite and rail you around a corner.  And *thats* where I see the transition from 'oh I am in too deep/too fast' to 'wow, that was freaking awesome'.

I would like to learn to do that a hell of a lot more, with a hell of a lot more intent.

 

 

[Jaybird180]

I love this topic. I too am focusing on my turning ability, specifically Quick Turning. There’s an article where Keith says that learning to QT solves all of the SRs. I’m striving to become a disciple of that.

[Lnewqban]

15 hours ago, Roberts said:

... On the pavement of a racetrack, the best equivalent is getting all the physics right to lean in hard enough and fast enough that your suspension loads evenly and firmly, and you can feel the tires bite and rail you around a corner.  And *thats* where I see the transition from 'oh I am in too deep/too fast' to 'wow, that was freaking awesome'.

I would like to learn to do that a hell of a lot more, with a hell of a lot more intent.

 

Thanks for your answer, Roberts.

If you have not done it yet, I would highly recommend you reading these old threads:

 

 

 

 

[Hotfoot]

This is a common enough question that lately Keith has put a new focus on the no-brakes drill with Level 4 students, having them re-do the drill to help increase their awareness of how much speed gets "scrubbed off" in a turn, and to make sure that concept is understood. There are, in fact, multiple Level 4 drills designed to increase the rider's awareness of this, and help the rider determine where, EXACTLY, one should have their entry speed set for a given corner. Dylan actually does cover this topic pretty thoroughly in the very first lecture in Level 1, Throttle Control, pointing out that the bike continues to slow down after the turn point, so trying to set your target corner speed AT the turn point can result in ending up too slow at the slowest part of the corner. However, I think for many riders who are new to track riding this speed-scrub aspect of throttle control may get lost; there is a lot to take in on that first day. And, of course, judging entry speed and speed scrub are the sort of thing that even the most advanced riders continue to work on, it does require focused observation and experimentation, and every turn is different so there is no "pat" answer that will work for every bike and every corner. Learning to observe the speed scrubbed after the turn point, and bringing up the entry speed gradually, is a good way to approach the problem - or make it a focus of your next Level 4 school day.  

[Dylan Code]

The answer to the question is: from turn-in, off throttle, not trailing the brakes, the bike will slow at the rate of between 3mph to 8mph/sec. Lots of variables of course but that's the quick answer.

[faffi]

I suppose the rate of turn-in as well as the amount of lean will matter greatly, as would speed itself through wind resistance?

[Dylan Code]

Yes, the amount of lean and overall speed from wind resistance would matter a lot. Turn-in rate would matter I suppose but not significantly. Wind resistance going straight requires a certain amount of power just to maintain a particular speed. A hypothetical example is here:

30mph=1hp

60mph=8hp

120mph=60hp

180mph=190hp

[Roberts]

Hey Dylan,

I am sure you get this a lot, but.....

Reading the information you put on the board feels like finding clues in mystery novel.  Like a real-life Divinci Code deal, only for motorcycle addicts.  I am still buzzing with the classroom time on physics, biology, mathematics, psychology, and the riddle of why motorcycles turn.

I really appreciate your contributions here.

[Dylan Code]

Thanks very much. We have more on the way!