Why MotoGP Engines Spin Backwards

How come #MotoGP crankshafts spin backwards, while cranks in regular street bikes spin forwards? What is the benefit? Time for a #techtalk!

[MikeonBikes]

Have seen a few comments questioning the physics behind this. Some comments contain questions, others assertions of how 'the physics are wrong'.


Specifically look 35 minutes in, where Walter spins a bicycle wheel and hangs one side of its axle on a string. The wheel stays upright and rotates around.

It rotates in different directions depending on which way he initially spins the wheel.

This should help you understand how a reverse rotating crank cancel out some of the gyroscopic effect of the wheels.

The wheels will precess in the opposite direction of the crank, because they respond opposite to the torque applied.

Spinning the crank in reverse is not some new invention, nor new realization. From what I can find precession was discovered by Greek astronomer Hipparchus around 190-120 BC.

Some motorcycles that have had reverse rotating cranks include: Yamaha TZ700, Honda NSR500, Honda RC166 etc.

Boxrepsol talks about introducing a reverse rotating crank in the NSR 500 in 1987. They were of course not the first ones to use this. "Another important adjustment made was the direction in which the crankshafts rotated to counteract the gyroscopic effects of the wheels, improving the bike-s performance in run-off areas. Even though the bike’s manoeuvrability improved, it did create the need to add an additional shaft to invert the spin direction at the engine’s exit, which slightly decreased its power."

Man out here answering questions that I didn't even know

[KyleMicena]

Only 2 current production bikes have reverse rotating crankshafts. The Ducati Panigale V4's, and MV Agusta F3 800/675. So if you're looking for the closest thing to a MotoGP bike any Ducati V4 variation is going to be your best bet. They're 5 years into the development of the V4 engine in production form and has the most GP derived technology. Truly a incredible and also beautiful engineering.

[pub]

I’ve been riding 50+ years and never knew about the backwards crank direction or gave it a thought, as you said….there’s always something to learn! BTW, you explained it all very well in a concise manner……which is a nice change on a YouTube video!

[ianhamilton]

I have a friend, that's a mechanic. Everytime I ask a question, he responds just to like this!! Very analytical! He is going to love this!!! Thank you!!! 😃

[louismartin]

counter rotating crankshaft also reduces inertia to changing direction - not just lean angle.
On motogop bikes they don’t care as much about longitudinal stability as much as the ability to change direction quickly.
For road bikes, safety demands the opposite.

[keisuketakahashi]

Thank you for this information . I was not aware of this engine rotation direction . Pretty cool how much calculations that goes into racing.

[manishverma]

Hello Mike. This is a very good and informative video. Make me realize how much we don't even realize about some technology that has been in plain sight.
I am also really interested in the showcased books. Whenever I get some time I will try to buy and read those, they look really interesting.
Meanwhile keep making these informative videos filled with passion for motorsports.

[jkjk]

Hope your wrist gets better soon Mike!

[CunningStuntsGoFast]

i went from the panigale 1199 to my current panigale v4s . the difference is inmense, the direction changing the v4s does is realy mindblowing . mind you my 1199 wasnt a s model so i went to a backward rotating engine and lighter wheels . dont know whats responcible the most for it tho . got some vids of my bike, maybe you like em

[francocelis]

Nice video, I see a man of culture if you read Tony Foale book. The only part I left for understanding later was the suspension part.. soo tough. Could you please make a video on how boxer engine gyroscopic behavior affects motorcycle stability.

Thanks and thumbs up on your work!

[firebladeadam]

Years ago when I was just a kid I was in the paddock at the IOM TT, I saw one bike (CBR600 from memory) being worked on by a gentleman who joked 'yeah, the engine in this runs backwards.'. I didn't get the joke then, but did soon after! Little did he know that years later it would be true.

[_Bike_is_Life]

Ducati Panigale V4 street engines are counter rotating. Almost all professional reviewers "complain" that they can't wheelie like they can on the KTM. They also don't use chain to drive the valve train allowing for higher RPM. These engineers don't get enough credit.

[jeffjefferson]

Great, this answered my suggested activity question (Chapter 1, question 3) from the book "Motorcycles Fundamentals, Service, Repairs".

Thank you!

Greetings,


Jeff

[WHITELIONNYC]

Never had any idea about this but I'm happy I learned something interesting to use as an icebreaker.

[mikcute]

Gotta be against the law to remove that classic outro music

[NatVirgo]

Small things like spinning the top with the injured arm help it heal not only faster but better. 👍

[kraftwels]

Great to see one of your videos again!
Your videos have great production value and are always interesting and informative

[mdeyab]

BTW, noticed your right hand ... hope you a quick recovery ;)

[Aegrim]

I don't understand why the engine going the other way would decrease stability? It's still rotating on a plane and won't want to change on that axis