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Ok, question of the week:

When the leaders start to lap the back of the field, how do the guys getting lapped know someone is behind them that they need to let through and not just some guy they're competing against for 17th place or whatever trying to pass?

http://www.motogp.com/en/MotoGP+Basics/flags_lights

Quote from: 1.21GW on July 22, 2013, 07:39:17 PM
Ok, question of the week:

When the leaders start to lap the back of the field, how do the guys getting lapped know someone is behind them that they need to let through and not just some guy they're competing against for 17th place or whatever trying to pass?

They're shown a blue flag

A lot simpler answer than I was expecting.  Flags just like track day!

I just rewatched Faster and it occured to me that there were a lot of high-sides on those 500c two-strokes.  The movie talks of how beastly those things were.  Nowadays, I only see low-sides in MotoGP.

It made me think: has the advent of electronic assistence changed the way MotoGP bikes crash?  That is, did TC and ABS reduce the probability of high-siding?  Or am I just working off of too few a number of observations?

Yep, the riders now rip open the throttle just as they're coming out of the corner. The ECU will calculate lean angle, front wheel lifting and rear wheel spin to determine just the right amount of power.

There isn't ABS.

But the answer to your question is YES.  There are two things at play here.  (well, there are a million, but I'll talk about two).  First, the switch from 2 stroke for 4 stroke engines.  Second, electronics.

2 stroke engines have a really non-linear power curve.  The power goes from nothing to EVERYTHING all of a sudden.  I've heard referred to as "getting on the pipe."  The sudden change in power as one got on the throttle made the 2 strokes ripe for a high side.  When the power poured on, the rear wheel would spin up and launch the rider to the moon.  4 stroke engines produce power in a much more linear and predictable fashion.  So even before lots of TC was introduced, the switch reduced (or should have reduced) the number of high sides.  then again, take a look at Lorenzo's rookie season.  Youch!

Electronics have also played a MASSIVE role.  As you can see from Pedrosa's crash last weekend (where MM clipped his TC sensor to his rear wheel and he immediately high sided), the riders have learned to trust their TC.  They're basically riding in a fashion that w/o the electronics, they'd crash every turn ('cept for a couple weirdos like Rossi and Stoner and *maybe* Hayden).  The electronics are dialed in to adjust not just for wheel spin, but for engine braking, and dialed in for each corner.  So, the computer controls how the bike is set up by corner.  Or rather, by each part of a corner.  It's a level of tuning that one could never achieve without electronics.  Basically, they have a bike that has different set-ups in different parts of the track and depending on how far along they are in the race.

It's a lot harder to high side because the bikes just won't let you.  Because electronics allow the riders to be that much closer to the edge of grip without worrying about the rear, they're much more likely to lowside because they just lose grip on the front (which is not controlled by electronics) than they are to spin up the rear (which is).  

Quote from: Spidey on October 04, 2013, 11:19:56 AM
The sudden change in power as one got on the throttle made the 2 strokes ripe for a high side.  When the power poured on, the rear wheel would spin up and launch the rider to the moon. 

yes frequently but not always, of course.

1.21: go look up some videos of garry mccoy riding a GP bike.    


also, occasionally in modern times GP bikes will 'forget' where they are on a given track and the result is usually disastrous.

Quote from: gm2 on October 04, 2013, 12:47:48 PM
also, occasionally in modern times GP bikes will 'forget' where they are on a given track and the result is usually disastrous.

more detail please.

See Nicky Hayden in Indy last year. ECU was somehow reset and delivered full power on a corner where Nicky did not expect it.

Quote from: Spidey on October 04, 2013, 11:19:56 AM

2 stroke engines have a really non-linear power curve.  The power goes from nothing to EVERYTHING all of a sudden.  I've heard referred to as "getting on the pipe."  

not a drug reference. 

http://en.wikipedia.org/wiki/Expansion_chamber

Re: leg dangle...

I just did a day with Dale Kieffer and he explained it (then showed me in practice and got me to do it). Instead of keeping your body aligned with the bike completely during braking, if you hang off to the inside and help set the bike up for the corner, you don't have any weight on your inside peg at all. All the forces under braking go through your BENT arms, torso and then your outside leg to that outside peg. Just like dragging a knee (or elbow) is nothing more than a feeler gauge for your lean angle (you can pull it up off the ground and still be at the same angle, after all) dangling the leg is a reminder to the rider about their position as they trail brake into the corner.

It's also a pretty big chunk of mass that you've now moved forward and down a lot (think of your rearset position on the bike: high and at the back). The bigger picture is to get your body in the right (awkward) position off the bike during braking and to get you braking "lighter, longer "... Trail Braking all the way to just before the apex at some corners.

Trying "the leg" to copy the MotoGP guys: no benefit at all. Trying it after Dale's lessons: wow, the bike turns a lot better and brakes a lot later.

so Lindz, what you are saying is it helps set up the bike for more comfortable and controllable trailbraking due to ballast movement more or less?

Yeah. But not nearly enough to be the only way to ride the bike, and as you can see it's only on certain corners (heavy braking after a straight, mostly). It's equal parts mental and physical.

It's a byproduct of an unweighted inner peg. The actual dangle is a conscious decision on style/technique. If that makes sense....