Balancing Throttle And Lean

[aslcbr600]

We know that a good line is one that allows you to use the throttle control rule correctly and hit all of your RP's. We also know that the less lean angle you use the more throttle you can use because of the added contact patch of the rear tire.

 

What I don't know is how to balance the difference between using lean angle and throttle, example you have a 90* elbow style turn and you take the turn with a little more lean angle due to a little higher turn entry speed. You know that the more you are leaned over the less aggressive with the throttle you can be right? So for just the sake of throwing out a number say you took the turn entry at 86mph with say 55* lean angle and less throttle.

 

Now you enter the same turn at 75mph with say 45* lean angle but due to more tire contact patch you can be a little more aggressive with the throttle then you could in the first turn scenario.....how do you balance those two out exactly to find the quickest way around the track?

 

I know not every turn is the same dynamic but what leaves me scratching my head is in KC's books it doesn't give you the "how to exactly balance the two" instead it's kinda left with some cloudy water and could be misinterpreted.

[YellowDuck]

I really don't know the answer, but here is an idea to contribute to the conversation that maybe others can then debunk

 

I would propose that, assuming you are on the most efficient line in both cases (the one that straightens the corner the most), the fastest combination is going to be the one that requires the greatest lean angle. Lean angle = corner speed, so if you are leaning less than you could have, the you entered with less speed than you could have. Yes, entering slower and thereby using less lean allows you to get on the throttle sooner...but the reason you can get on the throttle sooner is because you were going slow in the first place! I can't see how, in a symmetrical corner, carrying less corner speed could ever be advantageous on net.

 

But now I will listen to those who really know...

[bradvanhorn]

I do not believe you can pick one answer - there are too many variables in my opinion. Riding style, bike setup, track conditions, etc. All will influence the way you negotiate a given corner. I believe Keiths book The Soft Science of Road Racing Motorcycles does offer good data and method for developing a personal strategy on this point.

 

Scott Russell was talking about this in similar fashion during the superbike races at Daytona. Josh Herrin was spending a lot of time on the edge of the tire. Scotts comment was something to the effect of, "That is how Josh was used to riding his 600, but it's not necessarily as effective on superbikes. The 600s can carry more lean and speed longer. The superbikes want to get in, stop it, turn it, get it upright and on the gas as quickly as possible." Maybe I misheard but as I recall that's been a common theme on 600s vs. superbikes. It further illustrates to me why there isn't just one answer...

[faffi]

As tyre grip improves, we do see that even the bigger, more powerful bikes adapt the high lean/high cornering speed technique.

 

But back to the original question; wind on the throttle until you highside, then us a smidgeon less the next time

[Stroker]

You can throttle until the bike is unproductively unstable.How you judge this is up to you.

[ktk_ace]

my 2c and guesstimate:

 

choose a method that makes the suspension be in the mid range sweet spot on most of the turn imho.

bike is compliant in that range.

[tmckeen]

There answer to your overall question is simple, Lap Times, your basically asking how do you tell what's the fastest way around the track, and the answer is whatever results in the fastest lap time. Now as for the Corner speed vs Point and Shoot technique, that depends on tons of factors, there was a good article in RRW a few months back on the evolution of MotoGP technology and its effect on riding styles. Over the years as technology changed riding technique and corning lines shifted back and forth from one to the other, you used whichever style fit the equipment you had at the time, what sets the current state of MotoGP technology and the new breed of "Aliens" apart is that they no longer ride with one style based on the bike, but have to adapt the style to each corner individually.

 

also on a side note, I do believe you have more contact patch whilst leaned over due to the deformation of the tire carcass, standing the bike up isn't to increase the size of the contact patch, its to reduce the cornering load on the tire thus allowing more available traction for acceleration.

[aslcbr600]

Some good points, but more specifically what I am looking for is the balance between lean angles. Just because you drag your elbow on every corner doesn't mean it will give faster lap times.

 

Now one indicator I can come up with is if it feels awkward, like in TWOTII stated that excessive lean angle in a corner is slower, unstable and awkward. Of course that is one extreme to the other comparing too much lean and using max lean around a corner due to high entry speed. Looking to fill the gap on that middle ground.....does it just come down to more of bike setup and rider style then it does balancing lean angle and how aggressive you can get back to the gas?

 

I have the science of riding book but I will have to take a look through there and see if I can find anything on this.

[bradvanhorn]

Try chapters 9 and 10...

[csmith12]

Don't loose sight of what your goal with the throttle is.

 

Ask yourself... why do I need to hammer the throttle harder? Did we enter to slow and trying to get back the time? Trying to pass? Turn in to early to carry the speed? Not flick fast enough? Is just more throttle always the answer? What is the best time to hammer down on the throttle?

[faffi]

M&M use more lean than any other MotoGP rider currently. Yet he was fastest all 3 days in Texas recently. So do not rule out lean Also, like some have already mentioned, the specific corner, bike and rider combinations can require different approaches. In general, though, I will say that it is probably easier for mere mortals to learn to use more throttle than to use ultra-deep lean angles.

[Jasonzilla]

Someone's already said it: laptimes. The thing is that if it's one guy doing both of these around the same corner, he's more than likely turning at the same speed, so the increased speed and lean angle will end up being faster. I don't see how it wouldn't be.

[aslcbr600]

Went back through the book and what I ended up realizing is the more corner speed you carry the less you "have" to use the throttle for acceleration and speed just more for keeping the suspension compliant. Trying to "balance" the two seems counter productive because trying to make up speed by using less lean and more throttle only means you could have taken the corner faster as said above.

[Lnewqban]

Went back through the book and what I ended up realizing is the more corner speed you carry the less you "have" to use the throttle for acceleration and speed just more for keeping the suspension compliant......

 

Not exactly.

 

In ideal conditions, in order to properly load the tires and the suspension, the acceleration through the corner should be kept constant at a speed’s increment of 2.2~4.4 mph for each second spent on the turn.

 

As the speed increases during the turn, the entry speed should be such that leaving speed is not excessive regarding tire grip and/or lean angle.

 

Hence, the entry-out speed difference will be smaller for high speeds, precisely the conditions that generate higher skidding forces (lateral g's) and therefore, require better balance of tire's loads and better suspension's ranges.

 

For slower or higher radius turns, lean angles (skidding forces) will be less dramatic; hence, the acceleration may well be less than recommended in order to make the entry-out speed difference less dramatic (due to the increased time that the turn will take).

 

Also important: lean angle and associated lateral force are a consequence of speed and radius of turn only.

For the same constant-radius curve and trajectory, more speed generates more lateral force on the contact patches and more lean angle.

 

To put forces in perspective, the throttle rule creates a longitudinal force equivalent to 10% ~ 20% of the weight acting on each contact patch.

While that happens, the turning trajectory creates a lateral force that is several times bigger than that longitudinal force; if your lean angle is 45 degrees, that lateral force is equivalent to 100% of the weight acting on each contact patch.

 

Both forces are perpendicular to each other and parallel to the road.

There is a resultant force formed by those two; as long as that force doesn't grow beyond the circles of the schematic, you have grip; hence, when lean decreases (lateral force) there is room for acceleration or braking to be increased (longitudinal forces).

 

Consider also that for many tires the contact patch can be more or less (it is usually bigger when leaned, as purposely designed by manufacturers like Dunlop - See schematic below); however, the circle of available grip doesn't grow much simply because the angle at which the suspension is working when leaned makes it less effective.