Re: Cornering lines

[kwh@xxxxxxxxxxxxxxxxxxx (Ken Haylock)]

 > Date: Mon, 4 Jun 2001 11:29:06 -0400
 > From: Thomas Emberson <thomas@xxxxxxx>
 > Again, we are not on the track here. As far as decelerating,
 > traveling in the outer tire track then a sharp turn and accelerating
 > through the apex as you are straighening up (less lean as you hit
 > the has), that sounds like racing to me.

No, not really. Like I said, I set my speed so that I can stop in the
distance I can see to be clear, in longer (blind) corners I chase the 'limit
point' or 'vanishing point' and I stay 'out' until I can see the exit, i.e.
the point where the vanishing point disappears and the corner is obviously
over, and only then do I turn in harder towards a notional apex and exit.
Consider a horseshoe shaped corner, with a big lump of rock in the middle of
the horseshoe to stop you seeing right through the corner. On a racetrack,
you'd probably ride that as a big, fast, double apex corner, the ideal line
would look almost symmetrical, and you'd want to do it as quick as the bike
would get you round it. That big lump of rock in the middle of the horseshoe
would make no difference to the way you rode the corner either - the
marshals would tell you if there was a fallen rider on the racing line that
you might need to avoid. But on the road, even on a corner I knew well, my
line would be very different. On a right-hander (think left-hander in
American terms) I'd move to the outside edge of the road on the approach,
brake or slow to a pace where I could stop in the distance I could see, then
swing round the outside edge of the horseshoe, chasing the limit point,
before finally seeing the exit of the corner and picking my own apex between
where I then was and the exit, turning the bike quickly and taking a classic
'entry, apex, exit' line from  there on.

 > > If you just lean the bike over the same amount for any corner and adjust
 > > speed to keep it there, I presume that means you like to take smooth
 > > sweeping lines round every corner. How do you set your speed for entry?
 > > In a
 > > long decreasing radius turn, does that mean you either have to brake
 > > while
 > > cranked over or break your self imposed limit and lean more?
 >
 > Again, it is one of those things where I set my speed so I am at
 > 100% of my or the bike ability. If I get into a decreasing radius
 > turn I have more then enough traction left on the rear tire for
 > engine or light rear braking, and I always have a bit more lean to
 > go if I need it.

I've always believed that if I need to use the brakes mid-corner, I've
probably gone in too hot. If I ride to chase the limit point, and try and
ensure that I can always potentially stop in the distance I can see to be
clear, I should never be surprised by what a corner does next. The other
thing is I throw the 'line for the view' in the bin if the surface is dodgy
on the bit of road I'd need to ride on to use it, or there's another hazard
like a junction mid-corner that I want to be far enough out to be clearly
visible from, etc.

 > But the same could be asked of you, what do you do when you are
 > accelerating through the "apex" of the turn and you suddenly find
 > that the turns goes on a bit further that you expected or is a bit
 > tighter (decreasing radius). All of a sudden you apex is further
 > along the road? Obviously you would decrease the acceleration, but
 > you've already started the weight transfer to the rear wheel.

On a racetrack, the apex of a corner is where the apex is, and if you read
the circuit guides they say things like "turn in to Fred's Corner just by
the repair patch to the right of the end of the pit exit" and "apex late by
the far end of the inside kerb". But on the road I don't ever use classic
racetrack lines unless I can see all the road and all the surface right
through a  corner. Roundabouts (traffic circles) are good examples of where
one often can, but for the most part, I pick my own (late) apex once I can
see how the corner ends. For a short, sharp corner on the road, a late entry
means a better view than I'd have if took the corner on the fastest possible
line, as a racer would have done, which means I turn-in later than I would
f I were on a racetrack but I can see the exit before I even turn in, thus
squaring the corner off. This means in turn that I pick and use a later apex
than a racer would if it were part of a racetrack. Going back to long
corners again, I simply chase the limit point until it disappears and then
effectively start the corner from there.

[Suck eggs mode = 1]

The limit point (or the vanishing point in some texts) is the point where
the two edges of the road you are riding appear to meet. If they don't meet
before the horizon, there is no limit point and the road is straight - but
as soon as the road curves, those two edges appear to meet. The limit point
is conveniently the limit of the road you can see to be clear, so you can
aim to brake down to a speed where you could stop before the limit point if
you had to, allowing for surface conditions. Anyway, the limit point is also
extremely useful guide to what the corner you are in is doing. If you go
into a corner and the limit point is apparently moving towards you (meaning
that the edges of the road seem to be meeting closer to you than they were),
then the corner is tightening and you should roll off the throttle to slow
down. If it starts getting further away, then the corner is opening out and
you can wind it on a little way. Sometimes, in real nasty corners, it'll
start tight, open out and then tighten up again at the end. If you are
chasing the limit point (it will get closer, then further away again, and
then closer) then you aren't going to be affected by this rather nasty sting
in the tail... so if the limit point gets nearer, slow dow.

 > I think we can all agree, that on the street, when you don't know
 > the corner, being a bit more conservative is probably wise.

The secret is in chasing that limit point, IMHO. Do that and suddenly or
deceptively tightening corners hold no fear anymore.

 > Where the optimum lies between braking in steering input the right
 > the bike is beyond my skills. But in the one or two times I've had
 > to do something like that I came out okay.

It's amazing how quickly you can whack a bike from upright to full lean by
countersteering, and how quickly you can stand a bike up from full lean the
same way. And Keith Code is absolutely adamant that you won't cause anything
to unglue however quickly you do it, either. It seems to be true, from my
experience of turning in as quick as I possibly can by really prodding the
inside bar to drop the bike on its side on the racetrack. Turns out there's
no need to be easing a bike on its side, or standing it back up politely if
you need to do it quickly. Just give the outside bar a shove and it should
stand right up as quickly as you've a mind to tell it to...

 > >  > Anyway, got on the brakes and started to turn,
 >
 > that should probably be got off the brakes and started to turn in
 > again.

Ahh! Makes a bit more sense :-)

 > My point is, except for getting used to having a rear suspension,
 > I am pretty used to having wheels slide on dirt/ice/water/snow what
 > ever.

I can't say I actually like it, even on the dirt, but I take it far less
personally on knobblies on the loose than I do on sticky tyres on dry
tarmac...

 > > Strange how different people have different ideas about how to ride,
 > > isn't
 > > it. Who teaches the techniques you use and do they have any literature I
 > > might look at?
 >
 > Hate to admit it, but experience from 2 wheels of all kinds. I took
 > the MSF course in Ottawa (Bells Corners to be exact) and thats it.

Hey, maybe you might want to read a copy of that book I posted a link to,
then :-).

 > I really want to take a track course.

*Well* worth it, IMHO - if you do a good one. I do have to remind myself,
though, that for all that I learnt about bike control from reading the Code
books and then on a couple of race schools and machine control courses on
the track (and I'm a hyooge fan) plus several track days, if I rode on the
road the way I was riding on the track at Pembrey or Cadwell Park I'd
probably not live to a ripe old age.

Seriously, by the way, a decent track plus a fast motorcycle and some
quality instruction has absolutely awesome entertainment value. Go for it,
you'll not regret it and I predict you'll wish you'd done it years ago...!!

Ken Haylock - Sprint ST - MAG #93160

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                      * kwh@xxxxxxxxxxxxxxxxxxx *                     


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