tag:blogger.com,1999:blog-4650400550712092979.post3196165154890403484..comments2024-03-25T12:38:12.492+01:00Comments on Linkage Design: Lapierre DH Team 2013Antonio Osunahttp://www.blogger.com/profile/10075236093614144240noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-4650400550712092979.post-19718215567009887992013-03-07T20:28:52.673+01:002013-03-07T20:28:52.673+01:00I'm working mostly with Trailbikes, so I'l...I'm working mostly with Trailbikes, so I'll probably model the X-Flow.<br /><br />Best Regards,<br />Tony.Antonio Osunahttps://www.blogger.com/profile/10075236093614144240noreply@blogger.comtag:blogger.com,1999:blog-4650400550712092979.post-80614305814776176642013-03-07T20:24:20.300+01:002013-03-07T20:24:20.300+01:00Concerning the dynamics of the Lapierre DH Team. I...Concerning the dynamics of the Lapierre DH Team. Is it something that you can model in WM? Will it be one of the bikes in the library of models you are working on?<br /><br />Cheers<br />ChrisUnknownhttps://www.blogger.com/profile/17241896695243345163noreply@blogger.comtag:blogger.com,1999:blog-4650400550712092979.post-5297795502608388592013-03-07T19:37:56.735+01:002013-03-07T19:37:56.735+01:00Well, the thing is that nobody explains "anyt...Well, the thing is that nobody explains "anything", so it would be unfair to expect a good explanation from Lapierre, when their system is so complicated. <br /><br />VPP explained anywere? No.<br />FSR?? No.<br />DW?? Not really...<br /><br />The Pendbox has a lot of Kickback at the end of the travel, but the rider is probably not pedaling at that time, so it's not very important. The key of the system is low Pedal Kickback below Sag and having a different shape in the A1 Curve (It goes up...) and that's something that can't be analyzed with Kinematics, but it could make a difference in the dynamic response. <br /><br />Best Regards,<br />Tony. <br />Antonio Osunahttps://www.blogger.com/profile/10075236093614144240noreply@blogger.comtag:blogger.com,1999:blog-4650400550712092979.post-69810468067281706902013-03-07T19:09:12.498+01:002013-03-07T19:09:12.498+01:00Lapierre's account and justification of the pe...Lapierre's account and justification of the pendbox remains elusive several years after its introduction. <br /><br />First, it is an anti-bob mechanism - chain tension is said to exert pressure on the pendbox mechanism pulling and locking the FBB in its rearmost position resulting in excellent pedaling performance. Still, Lapierre grant that without sound kinematics chain tension would not rise sufficiently to provoke FBB movement. So, the effect could be considered minor and perhaps redundant.<br /><br />Then, there are the somewhat odd claims that the pendbox returns the FBB to the equilibrium position (SAG). Trouble is the shock does that too and the pendbox will never achieve what it is said to achieve without the support of the shock. Allowing that Lapierre has treated us to some descriptive oversimplifications of the pendbox it seems clear that the general idea is that the pendbox permits an increase in the degree of acceleration (assuming pedaling is uninterrupted by ongoing suspension activity) over what would be possible without such a mechanism (whether the suspension is currently compressed, extended or at equilibrium). So far, there has been no attempt at quantitative justification of the claim.<br /><br />Finally, there is the claim that the pendbox can deliver its benefits (anti-bob and enhanced acceleration) without noticeable costs - the suspension will respond normally to bumps and dips because of the clever inclusion of a bypass mechanism into the pendbox which means that bump force will always have precedence overriding other modalities. However, this can't be quite right because when bump force "overrides" the designed functions of the pendbox the FBB moves forward raising chain tension and increasing kickback above what would normally be caused by chain growth as the wheel swings though its path. That surely increases both the likelihood of impairment of suspension function and the degree of such impairment when it occurs.<br /><br />In the end the pendbox starts to appear to be more trouble than it is worth. For DH it seems to be a particularly dubious proposition. The small gains come at a high cost - elevated pedal feedback and chain tension have the effect of limiting suspension action. Where chain growth and pedal feedback are lesser concerns the pendbox makes more sense i.e. short travel bike.<br /><br />These comments do not preclude that the pendbox may serve some useful function that Lapierre has so far failed to explain.<br /><br />Un saludo Unknownhttps://www.blogger.com/profile/17241896695243345163noreply@blogger.com