Carbon Fibre frame

In keeping with its heritage, Ducati has been racing a steel trellis frame in MotoGP. Competitors have been racing stiff, aluminum frames. Next year, Ducati will race the Desmosedici GP9 with a carbon fibre frame. Arguably, it goes from the oldest frame design to the most modern in the paddock.


The benefits will be far greater stiffness and predictability from the chassis. Undoubtedly, this will make Nicky Hayden's transition from Honda to Ducati easier, because Hayden was accustomed to a stiffer, aluminum chassis at Honda. Will the GP9 put Casey Stoner back on top next year? Maybe the new carbon fibre chassis is the missing link to Stoner's second World title.


What about road bikes? Does it make sense to have CF frames for road use or are they similar to steel and can shatter from road induced vibrations thus making them less safer than conventional ones? I know it's more expensive to manufacture as it requires hand labour, but if price was not an issue do the benefits outway the drawbacks if there are any?

[jambo]

I'm not sure it's quite that simple. You can make a steel frame every bit as stiff as an aluminium one, it's just that for the same design, it tends to work out heavier. You don't actually want a completely stiff frame either. Flex in the frame and swing arm make up an increasingly important part of absorbing bumps at big lean angles. At 45 degrees of lean, a 10mm bump requires 20mm of suspension travel to absorb it, so a bit of flex helps the suspension out a lot, provided it's controlled and predictable.

Overly stiff frames have caused problems in the past, the Cagiva 500cc GP bikes of the 90's were massively stiff, and the riders claimed there was very little feel for grip because of it. When Honda was racing the SP1, they actually removed 2 of the 8 engine mounting bolts to introduce some flex in the frame, and the SP2's frame was designed to flex more.

There's a company down the road from me called carbontek that used to make a Ducati 916 Frame entirely from carbon. God knows what it cost or if it was any better though, nowadays they seem to just make fairing panels and the like.

Jambo

Originally Posted by jambo

When Honda was racing the SP1, they actually removed 2 of the 8 engine mounting bolts to introduce some flex in the frame, and the SP2's frame was designed to flex more.Jambo

Ah that was from Colin Edward's time in WSB, yeah I remember. Totally agree with what you're saying and the fact that Ducati are jumping from one extreme to another baffles me a bit.

Originally Posted by zunkus

Ah that was from Colin Edward's time in WSB, yeah I remember. Totally agree with what you're saying and the fact that Ducati are jumping from one extreme to another baffles me a bit.

Perhaps the logic works along the same lines as the Italians' typical long gap between updates (compared to the shorter one of the Japanese). If you want to maximise the time between updates, you need to make something really cutting edge when it's introduced. So, the old frame was now so dated it needed replacing and they replaced it with something that'd not need replacing itself for a long time? Maybe fifteen years from now we'll be having a similar discussion about why Ducati are still running an old fashioned carbon frame when everyone else has moved onto Adamantium ones.

Doesn`t Carbon have a Work life that wouldn`t make it worthwhile using on the street , and once you prang it , it can go either way to be ok or downright Cuffed

[SoulKiss]

Originally Posted by Ceri JC

Ducati are still running an old fashioned carbon frame when everyone else has moved onto Adamantium ones.

Of course then Ducati will move to Unobtanium

[jambo]

Originally Posted by xXBADGERXx

Doesn`t Carbon have a Work life that wouldn`t make it worthwhile using on the street , and once you prang it , it can go either way to be ok or downright Cuffed

Carbon fibre's plenty strong enough to be used in wheels, chassis of very high end cars, and, as it turns out a motorcycle frame if you feel the need.

But if you prang it, the chances are Maidstone Motoliner aren't going to be able to see it back to being OK Guess if you're in MotoGP it's less likely this is going to be important.

Jambo

Originally Posted by jambo

Carbon fibre's plenty strong enough to be used in wheels, chassis of very high end cars, and, as it turns out a motorcycle frame if you feel the need.

But if you prang it, the chances are Maidstone Motoliner aren't going to be able to see it back to being OK Guess if you're in MotoGP it's less likely this is going to be important.

Jambo

I was under the impression that lots of carbon fibre wheels had recommended "shelf lifes" in terms of mileage of typical road use. Sometimes as low as 10-15K miles. Fine for track bikes, not so good if you ride big distances and I imagine this number drop significantly if you're bumping the bike over kerbs etc. with any regularity.

[northwind]

Carbon'd probably have a limited lifespan, unless it was totalyl overbuilt which would defeat the purpose, but the average posey expensive bike doesn't do all that many miles anyway so it probably wouldn't be such a big concern...

Originally Posted by northwind

Carbon'd probably have a limited lifespan, unless it was totalyl overbuilt which would defeat the purpose, but the average posey expensive bike doesn't do all that many miles anyway so it probably wouldn't be such a big concern...

Indeed. I can't see many people dispatching/commuting long distance on a carbon framed special.