Motorcycle Handling & Chassis Design

Tony Foale's brilliant engineering manual, Motorcycle Handling & Chassis Design, gives you an inside, technical look at how motorbikes operate.  It also gives you some idea of just how precarious the act of piloting a motorcycle is.  Much is said about how free people feel when riding and the physics behind flying on two wheels makes it that much more magical.

That first time you roll on the throttle and your feet leave the ground not to come back down again for miles, you get that sensation of flight.  Your senses are alive on a motorbike as the world makes itself felt in many different ways.

The naked exposure you feel when riding is obvious.  What is less obvious are the hidden forces at work that allow you to do crazy things like hang sideways while cornering.

Anyone who has seen a racing motorcycle suddenly hit the ground can speak to how suddenly these balancing forces can fall out of sync.  Foale's book is full of helpful diagrams that clarify some pretty arcane physics.

Cornering on a bike is one of the most complex and misunderstood aspects of riding.  Keith Code does a good job of explaining this in Twist of the Wrist.  Foale's approach is more interested in the mechanics of the machine and how it handles the forces working on it.

From a rider's perspective, corning is a balancing act, but from the suspension's perspective things get a lot heavier when you're bending into a corner.

Compared to a car, motorcycles have very different dynamics that often surprise riders when they are testing the extremes of two wheeled dynamics.  Reading Foale's book (though he pitches pretty hard) is worth it even if you're only getting a sense of just how differently the 'integrated system' that is a motorcycle works.

Foale also gets into the geometry of the motorcycle.  From wheelbase and centre of gravity to more complex issues like how suspension height changes those fundamental forces.  Of course, in a corner a the suspension is severely compressed, changing the bike's responses in dramatic ways.  You get a real sense of how connected and complicated the physics of riding is after reading this book.

The copy I read was the 2002 version, but he still managed to work some of the newer computer based analysis of motorcycle physics.  Static pressure and its role on aerodynamics is a relatively new aspect of motorcycle theory, but Foale covers it.

You can find the latest version of this technical manual online from Foale's website, but you can get a good idea of what it's all about from Google Books.  I'm curious enough about changes and updates that I think I'm going to spring for the new PDF ebook.

MotoGP vs. Formula 1

A very expensive traffic jam

I just finished watching the F1 parade in Monte Carlo.  Watching the massive, modern F1 cars (so wide they practically fill the road) following each other through the streets of Monte Carlo reminded me why I've been watching MotoGP instead.  It's not uncommon to see multiple lead changes on a single lap in MotoGP, and dozens of mid-field overtakings during a race.  It's uncommon to see any lead changes in an F1 race and a driver climbing through the field has become a rarity.  At Monte Carlo this morning the only overtaking was political.

I started watching F1 during Michael Schumacher's rookie year and followed him all the way through his career.  My favourite race of his was '94 in Spain where he managed second place while stuck in one gear.  Spain a couple of years later was a master class in keeping an F1 car on the pavement in torrential rain.  While the engineering is interesting in F1 it's not why I watched it regularly for over two decades, it was because of the brilliance of the drivers.

I'm now into my second season of watching Motogp.  The first race I watched had a resurgent 34(!) year old Valentino Rossi chasing the astonishing Marc Marquez (beginning a record breaking run of wins) to a one two finish with multiple lead changes in a single lap.

It's hard to see just how much a MotoGP racer works their tires.

Slow motion is the way to go if you want to see just how much

they drift on a single wheel.

In one of the early races an announcer mentioned how in Formula One the car is the majority of the equation whereas in Motogp the rider is the key component.  From that moment on I made an effort to understand the complexities of riding a race bike.  Motosports that are decided by operator skill over engineering prowess (and budget) are what I'm into.  Schumi got that second place in Spain driving a second tier car.  When he started winning championships with a massive budget I was less interested.

Watching the parade around Monte Carlo reminded me of why I enjoy the bikes more.  With the rider such a big part of the equation, you'll see human excellence much more clearly on two wheels than you will with four. There is much less between a rider and the road than there is between a driver and the road.  While one is wrestling with their machine the other is setting suspension settings and adjusting engine maps.

With the Isle of Man TT coming up I'll also be able to see bikes battling on public roads just as the F1 cars didn't do on the streets of Monte Carlo. You see a lot of precision in Monte Carlo but you don't see the breath taking bravery that you'll see in the TT.  If you've never watched one before, give it a go.

This has me thinking about vehicle dynamics and the differences between motorcycles and cars... fodder for my next post...

From Tony Foale's Motorcycle Handling & Chasis Design: a must read if you're curious about motorbike dynamics

Some Links

Formula One vs. Motogp: vehicle comparison
F1 car mechanical and aerodynamic forces
Applying the fluid dynamics of F1 aerodynamics to motorcycle racing
The Physics of Motorbikes
Which is faster? F1 or MotoGP (by F1 fanatics)