| Author | Message | ||
     Trojan |
If the parts are attached to the chassis or engine then only part of that weight can be defined as unsprung weight. It is more complicated than a 50/50 split though and certainly beyond me. However, as I see it the shock is located on the left side of the chassis, so the linkage is unsprung as is a small part of the front of the shock. Likewise the front swingarm would be 'hybrid' weight just like a conventional rear swingarm, so again only a portion of it would contribute to unsprung weight. Normally unsprung weight is the parts o the bike that move with the suspension whereas sprung weight are parts that move with or are part of the chassis, so in conventional bikes the unsprung weight would be wheel, tyre, brakes, axle, lower fork legs etc. At the rear it is more complex but would normally be wheel, tyre, brakes, sprockets and only a part of the swingarm, chain/shaft/belt, and shock. On a hub centre steered bike you have to apply the normal rules for the rear of a conventional bike to the front of this one in order to get to what is unsprung weight. I think................ | ||
| Blake |
I think your clarification is accurate, the moving (relative to main chassis) portion of any front shock & linkage definitely contribute to unsprung mass. How much does the Vyrus front wheel/axle/hub/brake assembly weigh? An exploded view rendering or some photos might be informative. Interesting stuff. | ||
| Al_lighton |
Bottom line, if the part is moving as a result of the wheel moving, it's unsprung mass, regardless of where it is physically located. In the case of an inverted fork, the slider tube, much of the spring, the moving portion of the damper rod are all linearly moving parts of the unsprung mass that accelerate and move at the same rate as the wheel itself. In the case of a swingarm or front end like the Vyrus, again, any of the parts that are moving relative to the relatively fixed chassis, either linearly or rotationally, can be considered as unsprung mass. But instead of linear acceleration, much of the mass is being accelerated rotationally, so instead of just considering it's mass, you have to look at its mass moment of inertia, which considers not only the mass, but also how far from the pivot the mass is (a reasonably understandable wiki desription here: http://en.wikipedia.org/wiki/Moment_of_inertia ). But unless you're talking about a Suzuki TL1000 rotary damper, eventually, that polar moment gets converted BACK into a linear motion in the shock, regardless of where it is mounted. ALL of that motion needs to be considered as unsprung mass, and more is bad, less is better. But I think your last statement is essentially correct: "On a hub centre steered bike you have to apply the normal rules for the rear of a conventional bike to the front of this one in order to get to what is unsprung weight." But instead of counting sprockets and chains as unsprung mass at the wheel, you have to count the steering hubs and linkages. Back to Blake's original point, I admit to having some difficulties seeing the advantages to the Vyrus type front end. I'm not sure there are weight advantages, and linkages when new are probably fine, but linkages wear. The system just seems more complex than it needs to be. But I sure think that MotoCzysz take on an alternative to the conventional front end had some inherent advantages. I'm kinda suprised something like that hasn't gone further. | ||
| Jaimec |
The advantage to a swingarm front end is a COMPLETE separation of steering and suspension from each other. A typical telescopic fork combines each, and makes it particularly vulnerable to "bump steer." I've always like James Parker's RADD solution, as there were no funky linkages, just a direct link (steering tube) between the handlebars and the front wheel. Since Parker patented that system, however, Vyrus/Bimota had to come up with a different method. Maybe some input from Rube Goldberg too... BMW's Duolever and Telelever (as well as Czysz's take) still hold and support the front wheel with the mechanism that both supports AND steers the front wheel. | ||
| Blake |
I don't see how any front end is invulnerable to bump steer. | ||
| Al_lighton |
I haven't really thought about it all that much before. These videos are pretty cool for learning a little bit more about how center hub steering works. http://youtu.be/YMy5TXhcVcg http://youtu.be/Z_rP4DQOCrA I can see some advantages if the weights and inertias can be made comparable. Stiffness looks really high and easier to tailor. It seems to me that it's Vyrus form, it would be maybe TOO stiff laterally. I can see how it might lose feel through all the mechanisms. The wheel bearings sure look expensive... I'm not convinced that decoupling the steering from the suspension compressing under braking is all that great an idea anyway. In racing, the main reason you're ever braking is because of corners that you need to steer around. If the coupling was divergent from what you want when you're steering (i.e, if front end dive due to braking was BAD for steering), maybe decoupling them would be good. But it seems to me that conventional forks work kinda like you want them to now..that is, less rake/trail under compression when you're braking to turn in, more when exiting as the front expands. Tuning it so that you're getting the right amount of each at the same time is why you tweak the suspension to begin with, but once it is right, why would you want to decouple it? But it sure looks cool in a mechanical kinda way :-) The entire Vyrus looks like an insect or transformer or something. | ||
| Trojan |
I'm not convinced that decoupling the steering from the suspension compressing under braking is all that great an idea anyway. With the Vyrus system you can engineer in any amount of front end dive you want, from zero to the equivalent of a 'normal' front end (and probably more if you really wanted to). This is usually done to make the rider feel a more 'normal' riding experience though rather than for engineering reasons. When Phil first rode the Vyrus they dialled in quite a lot of dive simply because he couldn't get used to the bike behaving so differently to a conventional bike. As time progresses they removed the dive to the point where the bike hardly squatted at all on hard front braking. Conventional forks do have the advantage of shortening the wheelbase under braking and hence making the bike easier to turn, but once you remove the suspension and braking forces and stresses from the system the hub centre system workd amazing well and you just forget what a 'normal bike would be doing. One of the biggest advanatages is that tyre wear is far far less than on normal front ends. This is a good thing until you enter s race series which uses a spec tyre such as Moto2 or MotoGP, as the Vyrus needs to use a much softer front tyre than is currently available for use in these series. I think this will be th eonly stumbling block to the Vyrus Moto2 bike other than getting people to take the plubge and actually buy/race one. Al is right on the need to keep the steering conections/,linkages serviced and adjusted, but it is really no different to keeping a normal front end properly serviced and in race terms is just a routine maintenance procedure. | ||
| Trojan |
Back to WSB...... Laverty fastest on the Aprilia in testing following the final round of the WSB championship. Laverty was riding out of the Pata garage, but experts at the track deduced that he was actually riding Biaggi's bike from the last round. Good times too  It looks like Laverty will ride in a one man Pata liveried (factory supplied) team next year so that they can circumvent Biaggi's veto on team mate choice and on his insistence that he gets number one status in the team. By running Laverty in a separate team Biaggi gets no say in his treatment and will probably not be a happy man | ||
| Jaimec |
Where does that leave Nitro Nori? | ||
| Trojan |
Where does that leave Nitro Nori? He was talking about opening a pizza parlour in Nogoya at Portimao this weekend (seriously!). I think his days in WSB have gone now unfortunately, although there is still a chance that Pata will run two bikes of course.... | ||
| Jaimec |
Capirossi, Corser and now Haga? Time marches on... | ||
| Trojan |
Good news!! American wunderkind PJ Jacobsen has signed to race in World Supersport in 2012 for the PTR Honda team alongside Sam Lowes and ex BSB rider Martin Jessop (+1 other so far unnamed rider). I've been singing Jacobsen's praises for a long time and it is good to see him on one of the top bikes in the series and in a great team. I hope he does well next year  | ||
| Blake |
Wunderkind? Based on what? | ||
| Trojan |
Wunderkind? Based on what? Based on being the most talented teenager to come out of US racing (along with Jake Gagne) for a long time. You may not have heard much about him, simply because he spent a lot of time racing 125cc bikes in Europe. However he was the youngest US rider to enter a GP in the 2008 Indy 125GP (racing for the Aspar team). The same year he finished 5th in the Spanish 125cc GP series, the toughest 125 series in the world. He has been racing since 3 years old, has had a succesful dirt track career already (30 national youth titles) and did pretty well in his first full AMA DSB season this year (4 x top five finishes including 2nd at Miller) even though he suffered some technical issues during the year. He is without doubt one of the best hopes for a young US GP rider in the near future, and progress well under Simon Buckmaster in the PTR team next year | ||
| Smoke |
Josh Day will be racing the same series. good to see the young racers stepping up in the world series. | ||
| Trojan |
Who is Josh Day riding for? | ||
| Blake |
Matt, I put Ben Spies in the "Wunderkind" category. That kind of hype is just setting PJ up for a fall, one he won't deserve. | ||
| Trojan |
I put Ben Spies in the "Wunderkind" category. That kind of hype is just setting PJ up for a fall, one he won't deserve. I don't remember Ben Spies being in MotoGP aged 14? Spies was already a developed talent by the time he arrived on the international race scene. PJ Jacobsen, Jake Gagne and Josh Herrin are still developing and have huge potential. Should they continue to race in AMA until they have won multiple titles before they are put into WSB/MotoGP or should we encourage young racers such as these to get in early and take a risk? If you look at their respective youth records Jacobsen has probably won more so far at than Spies did at the same age, so how do you know that he won't be even better? | ||
| Jaimec |
Nobody really paid attention to Ben (who kicked Mladin's "donkey" three years in a row) until he hit the world scene in WSBK. While the rest of the world was shaking their heads in disbelief wondering "Who the **** is this guy???" we in the States knew all along. | ||
| Davegess |
guess it depends on how you define "wunderkind" but I would say Ben was way past childhood when he hit WSBK. Those youngsters certainly qualify and like it or not the have expectations on their shoulders. Hopefully they can handle the disappointments that may follow. I think child prodigies can really struggle when they reach a where they are no longer the very best. They can also be very spoiled and full of themselves so hopefully all these kids escape those problems and can enjoy being a kid and whatever success comes their way. | ||
| Blake |
Matt, I don't care where Ben was at what age; he was a MASSIVE talent recognized right from the start. Merely competing in a certain series make a racer a wunderkind. What 14 year old competed in MotoGP? Or did you mistype and mean 125GP or the like. I know anything to do with any kind of GP racing impresses the heck out of you, but it does little for me. If anything, PJ's dirt track experience will serve him most profitably in ever more competitive racing series. | ||
| Blake |
Dave, Ben won his first AMA championship at the age of ??? | ||
| Davegess |
Blake at what age did he compete in his first World Championship race. It sure wasn't 14. AMA racing is worlds away from the GPs. Sorta like comparing Major League baseball to Double A ball. | ||
| Trojan |
What 14 year old competed in MotoGP? Or did you mistype and mean 125GP or the like. I don't want to split hairs, but the MotoGP brand encompasses 125 and Moto2 as well as the MotoGP race itself. To compete at any MotoGP class at 14 is a huge achievement that you seem to disregard just because he didn't win an AMA title first? PJ certainly competed at world level a lot younger than Ben Spies did. I suspect he may end up with a larger trophy cabinet than Ben eventually too, but it depends on how he is managed in the near future. Simon Buckmaster is a great team manager and should bring him on just like he did with Eugene Laverty. | ||
| Jaimec |
Looks like Haga is done. And unlike Loris Capirossi, he didn't even have the chance to say "Good Bye." http://www.roadracingworld.com/news/article/?artic le=47067 | ||
| Smoke |
http://www.roadracingworld.com/news/article/?artic le=47068 provisional world supersport entry list PJ and Josh are the only american entries. John Hopkins only one in WSB(shared with UK) tim | ||
| Trojan |
I find it amazing that we (The UK) feel we have a national 'claim' to riders simply because their parents are British. By that logic we can probably claim Casey Stoner and a host of other 'colonial' riders if you look far enough back into their parentage Surely Colin Edwards must be Welsh with a name like that? And Hayden must be an old Anglo Saxon name from Yorkshire surely? I think it sometimes suits Hopper to play up to the 'dual nationality' hype, but I still cringe when it happens, especially with TV commentators. At least we have 3 'real' Brits at the sharp end of WSB this year anyway 4 if you include Eugene Laverty of course, although for some reason that defies geography and national borders he contends he's Irish (although opening that subject is probably a can of worms too far!) | ||
| Davegess |
he contends he's Irish Don't be starting that fight here Matt! He must be a Catholic lad! | ||
| Xb1125r |
I would like to see a race top 10 AMA superbike and top WSB teams. I would bet the an AMA would win it | ||
| Jaimec |
It would have to be best Two-out-of-Three to be fair. Round one on AMA spec bikes, round two on WSBK spec bikes, and then a third Supermoto round (neutral) before a winner could be declared, I'd think. First two rounds should be on the SAME track, preferably Miller, as they've all seen that one. |
