One way to resolve the perceived "midget problem"

I think you're underestimating adjustability a little. If you were
talking about identically prepared motorcycles, then yes, the
differences in tire choice and traction would probably go along those
lines, but even a stock bike can be set up for vastly different people
without sacrificing traction or balance. Have you ever set up static
sag on your bike? Played around with different ride heights?
Different spring rates? Different damping settings? Changing your
body position on the bike to affect the handling?

I remember a guy coming to see me with a more or less stock F2. He
was going to his first trackday and I volunteered to help him prep the
bike (water wetter, oil change, overall safety check). One of the
things we did was set up static sag and tweak his damping a little.
He was a big guy and was concerned about the bike's propensity to
wheelie. The things we did to the suspension were all done by fairly
general formulae to get him in the ballpark. I asked him to test it
around the block to make sure everything was good, mostly to make sure
nothing was loose and all the levers were still where he liked them.
He came back and said the bike was completely transformed. No
wheelying, no headshaking, way more confidence on the brakes. And
this is just a stock F2 with bare minimum of adjustments and bare
minimum of thinking put into it. Imagine how much a real engineer can
do with virtually unlimited chassis mods, not to mention suspension,
at his or her disposal!

 

Bruce Hartweg says:

Only if it's a picture window and a tornado I guess. Oh wait, you
meant braking.

The ARE above some velocity that is well within the realm
of a MotoGP bike. You can calculate them, it's not rocket
science.

http://www.motorpasion.com/images/20060910_motogp_podium.jpg

I'd guess Rossi has at least 36 in^2 more area just in the part
of his head above the midget. That's 7 ish percent of total
area. See the post I pointed to earlier and tell me where
the math is wrong. It's back of the envelope but I still trust
it more than seat of the pants. You're welcome to disagree
but until your math adds up, you're not even guessing.

V squared dude, V squared.


Go fast. Take chances.
Mike S.

 

i understand, once again i am NOT saying that the aero drag isn;t
happening. I am saying that a larger rider (in the sense of "big"
still being relatively small (Hayden, Rossi, etc)) does not have
very much aero advantage over the the mini guys (Pedrosa, Stoner)

you quoted earlier about aero being 25% of the force at some speed
OK - now look at the rider picture at motogp.com (can't direct link
because that site is a shitty flash blob) and look an Nicky & Dani
sitting beside each other. the CF of a leather wrapped body & helmet
are going to be pretty dang close, the frontal area is mostly the bike
and of the area of the riders, the helmets are not significantly
different sizes, nicky has a couple of inches at the shoulder so be
generous and say he gets a 20% increase in body area, but that is at
best only a 1/3 of the total area so the *difference* in braking effect
is only a couple of percent, and as this is braking we are dropping V
so the whole V squared things means whatever slight advantage it starts
out with drops off quickly.

so, once more, you do not need to "convince" me that there are aero
forces involved in braking, you do need more evidence that the larger
GP riders have any braking advantage over the smaller GP riders.

another non-math piece of evidence to the contrary. The teams have
way more detailed data and models than we do, if it turned out that
a slightly larger surface area was a noticeable advantage, everyones
leathers would be padded out to give them that advantage.

Bruce

 

The issue is not whether they have an advantage. The issue is that
their disadvantage due to increased mass is not as great as it might
seem if you only look at F=ma.

Not the case. Aerodynamic devices on leathers are expressly forbidden
in the MotoGP rule book. Shame, because I do have a nifty idea to try
out...

 

I don't see how that impacts things that much under straight-line
braking. All things being equal, the larger rider will have a stiffer
front end, to deal with the added rider weight. At the point of
maximum braking force all the bike's weight will be on the front tire
and the rear will be unweighted. How compressed the front is will
impact things, of course, but I don't think you can really generalize
on that between smaller and larger riders, can you?

 

So what is that hump on the back of riders' leathers? Don't tell me
that's a safety device...

 

We do keep circling back to the same thing, but what I hear is you
saying you love little GP bikes, so you favor the riders on them as
well, and as long as GP does that generally, you're fine with that,
the others can go race SBs. But MotoGP is where the real action is,
it's where the real money is spent, it's where the fastest bikes are,
it's where the best riders are. Or are supposed to be, which is where
my problem comes in - if it's truly the top series, and I think it is,
then it should strive to have the best riders and to have its champion
be the best of those riders. I think it's slipping away from that
these days because it seems it's more important to have its riders
come from its support classes, and to have the guys with the best
chance of winning be the guys from the countries with the most fan
support. In other words, money does all the talking, championships are
bought and not earned. You think that's fine, and I don't. It's pretty
simply, really.

 

Well, the point is that settings are tailored to each rider. If you
have a bigger rider, you'll probably set up the chassis for less
weight transfer all around, also, probably a little more nose-high.
Might lengthen the wheelbase some. This is getting beyond my
experience here. The point though, is that the differences between a
small and a big rider that are pertinent to managing traction and
weight transfer may be offset to a great degree in the setup.

 

If you're equating smallness of riders with geography, that's bull.
If you're saying, bike development is suiting riders coming from
Europe-friendly series, well, that's because there is fan interest
there and therefore sponsorship dollars. And you're saying that on
the heels of an American having won a championship. I think that's
ironic. I'm tired of beating this dead horse with you, but why is it
unreasonable to expect fan interest to dictate sponsorship money,
which in turn dictates to a degree which riders get hired (in no small
part because they bring their own sponsors a lot of the time)? I
think we've both said all we have to say on this issue.

 

You're still saying the larger rider will have the advantage, and I
don't think it's true. He may have some minor advantage at the highest
end of the speed range, but that drops off very quickly, and most of
the braking is done when the aero impact difference is negligible. I
still think a larger rider is at an overall disadvantage under braking
over a lap, because of his higher mass. Not huge, but something.

 

Larger riders aren't hired at the top level of the sport because rider
size/weight is a disadvantage in bike racing, just as the bikes aren't
bigger or heavier than they need to be, and that's always been the
case - the top guys in SB are no smaller than they were 15 or 20 years
ago. There probably have been some guys who have gotten screwed in the
process, but it's unlikely that much real talent has gotten squeezed
out. But in MotoGP things have gone way beyond that now, and it's
unlikely because the people doing the hiring really think these guys
are better. To the extent that bike development is done to make the
bikes easier for riders with a 125/250 background to ride, it
exacerbates this trend. If you look at MotoGP that seems to have been
the case, from the slipper clutch work that was done in the early days
to the electronics advancements to reduction in displacement this
year. It's all about cause and effect, and I don't think the factories
all have been purely trying to make the fastest, best bikes, rather
they have been doing so for the guys who would be riding them. And
those guys aren't simply the best riders, rather they are the most
successful riders that 125 and 250 produces.

 

Well, looking at next year's MotoGP rider pool, the five lightest
riders are all from Spain and Italy, and the five heaviest are all
from the US, Australia and the UK. Just coincidence?

Add that the new champ is from Australia, and even though he took the
125/250 route that just adds to the irony.

I'm tired of beating this dead horse with you, but why is it

Yeah, and I suppose you're a guy who would be fine with the American
professional team sports leagues setting up their rules so LA plays NY
in the championship pretty much every year - why would anyone expect
anything else? That's where the big money is, and if you're from, say,
Phoenix or Denver, then you're just screwed...

 

nahh, extra padding is a safety feature

 

It's a shape designed to reduce aerodynamic drag, which is not the
same as an aerodynamic device. Aerodynamic devices attempt to
_manage_ air, which the hump does not. And yes, it does have safety
benefits.

 

I'm not saying that a heavier rider has advantage. I'm saying the
disadvantage is not as high as one would glean from looking at braking
without aerodynamic variables.

 

I don't know what that means. Don't follow stick and ball sports
much.

One other thing I don't understand. I give you lots of credit for
being passionate about the sport, though I suspect you have some kind
of under-the-surface disdain for amature racing. Hope I'm wrong on
the last count. Having studied the history of the sport and attended
so many events, and having formed such strong opinions on what's wrong
with the MotoGP series, what are you doing to improve it? And if you
think you can't do anything, I hope you've heard of the guy named Liam
Schubert.

 

Hah! Now there's a perfect example of double-talk! Tell us how the
humps don't "manage air". That's exactly what they do.

 

It's a shape designed to reduce aerodynamic drag, which is not the
same as an aerodynamic device. Aerodynamic devices attempt to
_manage_ air, which the hump does not. And yes, it does have safety
benefits.

 

Mark, I maintain that your assertion that a heavier rider will find
him/herself on equal footing if the lighter rider's bike is ballast is
flawed. What part of "adding weight is not gonna make it the same" is
unclear?

 

Managing air means you do something with it. Creating downforce is a
good example of that. The hump on the leathers does not create any
forces, rather it serves to smooth out the air going over the rider.
Essentially it's an anti-turbulence device. To recap: it doesn't
generate aero forces. That's what makes it legit.