Race chassis

[Grumph]

Quoting Mike.
This method of assessing a frame in isolation by anchoring it in a jig and then applying stress and loadings was adopted by most team and, as a result, the concensus was that aluminium was preferable when compared to carbon.This was not only as a result of the FIM raising weight limits. Admittedly,aluminium had the advantage of being cheaper, but it was also easier to produce a structure with the desired bending-twisting behaviour. Did we need the extra stiffness potential that carbon offered ? No. Carbon also has a reflex response range (in hertz) that you don't want motorcycle frame componentry to be in. In some carbon structures, like a yacht mast, you need that rapid reflex response, so when the wind powers the sail the mast rebounds quickly. When a motorcycle is on it's side going over bumps in a corner you don't need that sort of rapid reflex, we want the frame to unwind in a predictable way.
When you get a frame that has no feel,it may be a brilliant machine but they are only riding it (at) 95%.

Quoted for information only - and not to stop you going out and buying a copy. Please buy one....

My own thoughts on this are that slowing the reflex response works because it better matches the response of the human pilot. If we had synapses as fast as computers we may be able to live with very fast reacting frames...

[190mech]

Perhaps in the future we will have pilotless motorcycle races like aviation is coming to now...How exciting!!

[husaberg]

Quoting Mike.
This method of assessing a frame in isolation by anchoring it in a jig and then applying stress and loadings was adopted by most team and, as a result, the concensus was that aluminium was preferable when compared to carbon.This was not only as a result of the FIM raising weight limits. Admittedly,aluminium had the advantage of being cheaper, but it was also easier to produce a structure with the desired bending-twisting behaviour. Did we need the extra stiffness potential that carbon offered ? No. Carbon also has a reflex response range (in hertz) that you don't want motorcycle frame componentry to be in. In some carbon structures, like a yacht mast, you need that rapid reflex response, so when the wind powers the sail the mast rebounds quickly. When a motorcycle is on it's side going over bumps in a corner you don't need that sort of rapid reflex, we want the frame to unwind in a predictable way.
When you get a frame that has no feel,it may be a brilliant machine but they are only riding it (at) 95%.

Quoted for information only - and not to stop you going out and buying a copy. Please buy one....

My own thoughts on this are that slowing the reflex response works because it better matches the response of the human pilot. If we had synapses as fast as computers we may be able to live with very fast reacting frames...

My own research also pulled up the frames were not repairable in the event of a crash, They were not so great at absorbing vibrations either , as the harmonics are totally different from alluminiun just as steel is totally different from aluminium,
Also they needed a complete new frame, if they wanted to change a few variables ie mount location or geometry. Aluminium and steel are much more forgiving
There was also at times “noise” issues with electronics.
I know the Britten suffered from this also as well as some other electric issues until someone twigged carbon fibre frames were quite a useful electrical conductor.

With regards to the flex response i believe its to do with the suspension not working very well when leaned over at extreme angles thus with some less laterally less stiff chassis, this chassis flex, along with the tire carcass, becomes part of the suspension system

[F5 Dave]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike.../9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

[husaberg]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike.../9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

What does he say about the dog Coaxial swingarm chassis that had them having to run off and get ROC chassis that were actually acopy of their old ones.

[F5 Dave]

And that I can't remember but was covered. There was the bit that they measured and found the supposedly flexyer chassiswas stiffer. TThat'swhen they realised the concept was a bit lost in ttranslation.


I gave the copy back Friday.

[Frits Overmars]

When a motorcycle is on it's side going over bumps in a corner... we want the frame to unwind in a predictable way.

With regards to the flex response i believe its to do with the suspension not working very well when leaned over at extreme angles thus with some less laterally less stiff chassis, this chassis flex, along with the tire carcass, becomes part of the suspension system

You guys nailed it. With a bike leaned over, we need lateral flex over the bumps, hence the search for the optimum amount of frame flex, as opposed to maximum frame stiffness.
But for that frame to unwind in a predictable way we need damping. Better still: we need a frame that won't twist, equiped with additional lateral dampened suspension.
Then we can forget about 'optimum frame flex' and build alu/steel/carbon frames with maximum stiffness again.
Take a look at this:
https://www.facebook.com/Suspensions...type=3&theater
https://www.facebook.com/Suspensions...type=3&theater

[guyhockley]

Just ordered my own copy

http://www.fishpond.co.nz/Books/Mike.../9781869539566

$35nz free delivery in nz but pounds to dollars will still be a cheap book to UK .

Cheaper to buy direct from NZ with shipping costs than from the UK supplier!

[guyhockley]

There you go... a chassis with stiffness reducing holes!


Seriously, though, I was at a party at my brother-in-law's and one of his relatives had been working for Lotus. He knew the bloke at TWR in charge of dealing with Team Roberts. Apparently the car people were initially quite condescending until they saw the huge amount of data and detailed specs TR had. The real eye opener for them was being given a range of stiffness for chassis parts as car design normally aims for the maximum possible.

[Grumph]

There you go... a chassis with stiffness reducing holes!


Seriously, though, I was at a party at my brother-in-law's and one of his relatives had been working for Lotus. He knew the bloke at TWR in charge of dealing with Team Roberts. Apparently the car people were initially quite condescending until they saw the huge amount of data and detailed specs TR had. The real eye opener for them was being given a range of stiffness for chassis parts as car design normally aims for the maximum possible.

The pic Mike showed me at Levels of a 500 Yamaha frame "swiss-cheesed" was from Paul Treacy's collection and unfortunately isn't in the book.
But it did indicate the lengths they were prepared to go to in search of hard data.

[husaberg]

The pic Mike showed me at Levels of a 500 Yamaha frame "swiss-cheesed" was from Paul Treacy's collection and unfortunately isn't in the book.
But it did indicate the lengths they were prepared to go to in search of hard data.

Honda (More likely Kanemoto)did something with i think Biaggi's NSR250, that basically involved cutting out sections of the cross members, Bits of frame spars and engine/swingarm plates. I think they even unhooked the engine so it was not a stressed member.
From what i understand Max would not even tell Erv what he prefered for suspension, tires setting or anything until just before the race. Just in case it leasked out
I have a piece on it somewhere, Caladora who rode very different sweeping lines never had the same problems with the same bikes.

[Grumph]

According to Mike in the book, Cadalora was different to everyone. Very light on brakes on corner entry. Running alongside Rainey, the telemetry was vastly different. Rainey, very high brake pressure, Cadalora, very light pressure. Totally different style.

[Manu24]

(Advice from husaberg, I publish here)

Hola, mi nombre es Manu y yo soy de España, hace un par de años, he hecho a mi equipo ktuning.es una bicicleta de carbono, ahora les presento la siguiente evolución 80cc motor de 2 tiempos, espero que sea de su agrado, saludos !

https://www.facebook.com/Ktuning.es/
www.ktuning.es

[guyhockley]

Team Roberts stuff, the picture of the storage rack on the second page shows the stages of fabrication of the frame spars (pre John Barnard). Also, note the rejected carbon swinging arm.

[husaberg]

Team Roberts stuff, the picture of the storage rack on the second page shows the stages of fabrication of the frame spars (pre John Barnard). Also, note the rejected carbon swinging arm.

Anyone able to franslate froggy to the Queens tongue.
I give up is all i know.

(Advice from husaberg, I publish here)

Hola, mi nombre es Manu y yo soy de España, hace un par de años, he hecho a mi equipo ktuning.es una bicicleta de carbono, ahora les presento la siguiente evolución 80cc motor de 2 tiempos, espero que sea de su agrado, saludos !

https://www.facebook.com/Ktuning.es/
www.ktuning.es

Nice suff.