Re-inventing the racing motorcycle (from MCN)

[The Phantom]

Interesting stuff.

http://tinyurl.com/yvtzt6

The swingarm pivot point is very narrow to allow the riders feet to be closer together (the idea being to lower the rider in the bike to improve aerodynamics). They do this by running the final drive up the _centre_ of the pivot, then move it outboard with a shaft. Some drivetrain losses of course, but it would be relatively negligible.

However, I do wonder whether moving the pegs to maybe 30cm apart will negatively affect the technique of weighting the pegs to help steer the bike?

http://www.motorcyclenews.com/upload/194970/images/Rear-Swinging-Arm-Assy-3.jpg

[ChrisS]

A lot of designs that re-invented the racing motorcycle appeared in the past.

The bikes however still remain based on the old designs and the main reason for that is the 'feel' of the bike. new designs 'feel' different and the riders cant understand the bike

[jim mcglinchey]

The drive chain is no longer horizontal, would the fact that its axis is inclined at about 45 degrees not tend to lift the rear wheel off the ground during acceleration?

[ArmchairBikeFan]

F1 designers realize that bike designers know nothing about bikes, and F1 designers can do better!
Ilmor, anyone? :)

[The Phantom]

F1 designers realize that bike designers know nothing about bikes, and F1 designers can do better!
Ilmor, anyone? :)

LOL, yes it's always good sport when F1 steps into motorcycle design : )

I wrote something this week on another forum I'm on (prompted by a question regarding the ELF badge on the swingarm of the VFR750:


In 7 or 8 years of scratching around various VFR boards I've never before seen the SSS badge come up as a topic... so why not keep it going.

Interesting, the ELF connection. I've never considered it much before, but now that I do - I assume the ELF in question has something to do with the ELF that were involved in the six-wheeled F1 car (Tyrell P34), and so, they are an F1 constructor or supplier? The F1 connection has been a cruel mistress for the plethora of designers trying to get that engineering leap forward; but perhaps their zealous hystronics of over-engineering were just what was needed when Honda wanted to race with a single sided swingarm, in that most extreme of extreme sports, F1 and Superbike endurance racing.

Zero flex, +/- zero tolerances, zero idea at all when it comes to what makes for fast racing motorcycles - it makes sense now, when you realise that a single hard, beautifully shaped, engineeringly 'made' as good as any mafioso, and unflinchingly uncompromising piece of state of the art alloy, would be F1's ultimate gift to motorcycle racing. An unmoveable, blunt, point a to point b bit of metal - a lever, more or less, being an engineering marvel since its discovery, oh, 40 000 years ago? As a case in point, it's hard to argue that any other F1 contribution has really paid dividends compared to the one-piece dumb-as-a-hammer swingarm that ELF came up with for Honda's endurance racing bikes... automatic shift? no thanks. 240hp like a lightswitch at 15k rpm? ahh, might pass on that. traction control? arghh, only if I have to... but that bit of curved aluminium billet over there, on the bench next to the 14' high milling machine; do you mind if I have a closer look at it...

(previous paragraph loaded with enough big eff-off 'engineering meets art' terms of reference to bring Jeremy Clarkson to his knees )

Did Honda want the ELF connection as a way to link to some euro bike constructor 'cred', like that enjoyed by the Japanese side, way back when bespoke chassis manufacturers outnumbered the amount of actual motorcycle manufacturers. and Japan's sports motorcycles sported chassis features which dealt out truly terrifying handling to white knuckled riders - who were, nevertheless, thrilled by the power on offer. Boffin own goal ever ever there was one - when the Japanese got their OEM chassis engineering up to scratch it was bye bye, Rickman, thanks for coming, Harris. Well, not quite, a few survived with other ventures. But anyway, rambling again - so did Honda buy into a little race-scene cred, or did they really feel their mighty engineering brain could use a bit of whatever it was they were smoking in Europe?

Honda builds everything from outboard motors to downhill racing mountainbikes with automatic gearboxes, to personal jets these days; one would think that they'd not at any point feel the need to outsource engineering requirements for anything, let alone something that they were experts at. And neatly back to motorcycles, and the apparent failing of the 2007 800cc MotoGP bike from Honda. Failing, interestingly enough, because of inherrent flaws in the design of the chassis. Message to Honda Racing Corporation - bring in ELF!

[ArmchairBikeFan]

The Elf who teamed up with Tyrell were the French oil company called Elf rather than an engineering company. I think they sponsor Kwaka in MotoGP.
It's easy to come up with a great idea on the back of an envelope and draw a picture of it in Photoshop, but when you test it and the rider tells you it's rubbish, what then?

[Valentino Rossi]: The pegs are too close together.
[Designer]: But it lets us lower the centre of gravity.
[Valentino Rossi]: You are... How you say... An idiot.

[The Phantom]

LOL! Is velly funny : )

Rossi's shown in the past that he is not one to mince words -

"You are... How you say... A F***ING idiot" : )

[ArmchairBikeFan]

I remembered reading something about one of the Honda 500's having its centre of gravity too low and not handling properly, so did a quick Google and found an article on the NSR500 on "Soup":
http://www.superbikeplanet.com/NSR500.htm
Seems that if the centre of gravity's too low, the riders can't shift their weight back and forth to balance the bike under acceleration and braking.

[maxu05]

Shifting the weight around on the Honda is going to mean squat, as the Duke is going to kick it's a... IMO. Centre of HP and RPM's is the go matey :laugh:

[Kneeslider]

If you look at a modern racebike, you will probably find that the footpegs are already less than 30cm apart. As far as I see it (on my own bike at least) the limiting factor occurs when you have the balls of your feet on the footpegs, (which is where they should be when cornering to stop rubbing the outside of your foot on the floor) and then your heels are as close together as would be allowed by the width of the rear tyre. Making the swing arm pivot narrower will lead to a loss of torsional rigidity between the swing arm pivot and the headstock (where all the forces on the frame are resolved)

I can't really see this 'innovation' being a great leap forward.

[Kneeslider]

The drive chain is no longer horizontal, would the fact that its axis is inclined at about 45 degrees not tend to lift the rear wheel off the ground during acceleration?


No, when you think about it, the shape of the arm, matters least of all. The crucial thing it the height of the swing arm pivot relative to the position of the gearbox sprocket. If you put the pivot higher than the gearbox sprocket, then, under power, the chain will try to pull the back sprocket towards it'self, and the rear of the bike will rise. Put the swing arm pivot too low, and under power the rear will squat. Some exotica has adjustable shimming to alter this.

But it's not as simple as that.

If you put the pivot point in the middle, where it might be considered to be the optimum, that only works when the suspension is in one place, and unfortuantely, it won't stay there!

[Kneeslider]

Remember also that a low centre of gravity is only a good thing when you consider the design of a car. With a motorcycle (as Honda found out with the NSR with the underslung fuel tank) it's more complex than that.

Why is it that when you raise the rear end of your streetbike with either the ride height adjuster, if you have one, or increase the pre load on the rear damper the handling feels 'better' have you not also raised the CofG? :D

[NinjaMaster]

Kneeslider you post whore! :D

[tha_jackal]

Kneeslider you post whore! :D

Im with Ninja :p such facts and knowledge are not welcome here! :laugh: This is a place of rumour and gossip! How dare you :D :D

[maxu05]

I agree, we should have more gossip. Facts, ha, the world can't cope with that stuff (just ask the newspapers). Tha Jackel, wears womens underwear, and Ninja sings Michael Jackson songs at Karaoke, now that's Gossip :laugh: (boy, I'm going to get it now) :laugh:

[Kneeslider]

Kneeslider you post whore! :D


Yeah, yeah. Guilty as charged!

[NinjaMaster]

I agree, we should have more gossip. Facts, ha, the world can't cope with that stuff (just ask the newspapers). Tha Jackel, wears womens underwear, and Ninja sings Michael Jackson songs at Karaoke, now that's Gossip :laugh: (boy, I'm going to get it now)

Yeah but my singing is poor so it doesn't count! :laugh: And I'm sure Jackal only wear womens underwear for the comfort! :D Oh, and I heard a whisper that Denise Richards recent relationship failure may have been over a certain Maxu. Just keep it under your hats though. :love:

Oh, and I don't think we could possibly get further off topic if we tried. :s tareup:

[tha_jackal]

Hmm, a LONG way off topic .. But yes, it is strictly a comfort thing :D