This is fun...

I'm very happy to put up this piece by the world's leading FF race expert. It's a bonanza for social media trolls everywhere, enough material to keep them off the streets forever. For those on the street, race or otherwise, Rob offers some really interesting innovations in dynamics, extending the FF performance envelope. Think before you troll. This guy has actually raced this stuff. Great thing racing. Put up or Shut up.
Nice one Rob. A happy holiday and a better new year;-

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Fascinating stuff – and the opposite view from Kevin Cameron

Amazing coincidence that Rob Horn has posted his fascinating article a few weeks after Kevin Cameron posted one on the Cycle News website demonstrating, apparently, that a high CofG is better than a low one, complete with examples of the evils of low CofG as displayed in the 1984 Honda GP bike with underslung petrol tank. I'd love to see the two of them argue it out face to face, preferably with Messrs Creasey, Foale, Hossack and Wagner in the same room to add comments of their own! I'd also love to see a properly scientific experiment on a track with fully adjustable powered two wheelers; seat height, wheelbase length etc etc...and identical motors. CW, Nov4th 2020 'Motorcycle Center of Gravity Motorhead Myths; Does low CG guarantee good handling?'.
See here:
FWIW, my own experience with the Flying Banana vs a standard Honda CX500, Quasars, Ecomobiles, Monotracers and of course the Gurney Alligators (amongst many other FFs) is enough to keep me believing firmly in the virtues of a low CofG...

Scientific studies

Blez asked for an ideal which can't really be met. One cannot change only one thing in most experiments, especially one with as many variables as a motorcycle.

No Guarantees

It seems that the answer to the magazine article is no. In fact nothing can guarantee good handling. As Arthur points out, there are too many variables.

Perhaps the trend on moto GP bikes does not actually raise the CoM, but just appears to. It wouldn't be the first time that a journalist has been deliberately misled in order to throw others off the scent after all. Without data about the bikes, we shall never know.


Emails from KC, now quite old, claim not to understand physics well enough to follow the CG argument, and that Cycle World cannot be expected to investigate FF advantages, including safety, because the readers aren't interested. So much for that. Anyone who does understand physics, unfortunate enough to have read KC latest piece will note that his own arguments seamlessly extend to disprove the point he's trying to make. Like many non-technical observers he makes the basic mistake of not realising the the riders weight is part of the CG anlysis, and the largest single element at that.

To repeat, raising the CG of a motorised bicycle reduces polar moments, if the rider sat on top is included and thus should reduce intial roll inertia. However, lowering the rider has exactly the same effect while reducing CG with all the well-demonstrated advanteges. Roll centre will always be somewhere between the contact patches and the CG, depending on exactly where in the process of intiating and controlling roll the vehicle is. Lowering it always reduces wheel unloading during roll.

The fact that these simple physics are still being argued over (forty years now?) indicates the lack of understanding possessed by many journalists and so-called motorcycle engineers across the world. I've had enough of it. You have a theory? design an experiment to test it, publish the results, do what you can to embody anything that looks usefull. It's what everybody else did. Put up, or shut up. We're fucked far past arguments about the quality of PTWs to be relevent to the world!

If physics is too difficult, start by asking people what qualities they actually need in a PTW. Comfort, Handling, Safety? Even efficiency. You'll end up in the same place.

Lack of combustion?

Disapointing lack combustion in comments on this thread so let me add some more fuel. You want to compare low CG directly with High CG? Easy. Find yourself a 2010 Yamaha Tmax. Then go and get that nice Mr. Rohit Jaggi to lend you the 2010 Cmax. This is a stock Tmax with the minimal FF additions. A low seat and seatback, Footboxes, some bodywork. Nothing else was changed. Design some experiments, hire yourself a session at MIRA and you can drectly compare eveything. MIRA isn't cheap, except when compared to the cost of building an FF prototype like this. Then everyone will know, the arguments can stop and we can focus on why Yamaha, or any other manufacturers, are too chickenshit to do this themsleves. Don't forget to tell KC!

Or, do the other thing...