Vasttech design
Posté : mar. févr. 21, 2023 7:26 am
Vasttech design c'est la société qui a conçu le système de suspension.
La marque du bike c'est Veli.
https://veli.bike/index.php
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Re: Vasttech design
Posté : mar. févr. 21, 2023 11:37 am
Re: Vasttech design
Posté : mar. févr. 21, 2023 11:57 am
Merci Pat , oui le vélo veli me c est un prototype aucune intégration, pour le fonctionnement de la suspension il y a sans doute comme expliqué des intérêts, mais elle doit très fortement influencer le freinage, et une articulation aussi imposante soit elle au milieu des bases …quid de la rigidité et prise de jeu ? C est justement à cet endroit que les contraintes provoquent des casses sur certains cadres rigide …
Re: Vasttech design
Posté : mar. févr. 21, 2023 12:56 pm
Vu sur les vidéos, il y a aussi pas mal de Kick-back.
Apparemment c'est du 29" à l'AV et 27,5" à l'AR.
Pour l'intégration, si tu parles bien de l'intégration des câbles et durites, ce n'est pas prévu, ils sont contre ça.
Apparemment c'est du 29" à l'AV et 27,5" à l'AR.
Pour l'intégration, si tu parles bien de l'intégration des câbles et durites, ce n'est pas prévu, ils sont contre ça.
Re: Vasttech design
Posté : mar. févr. 21, 2023 1:32 pm
Oui pas d intégration mais un Rilsan sur le top tube 
Re: Vasttech design
Posté : mar. févr. 21, 2023 2:03 pm
c'est massif et pas très joliePat2A a écrit : ↑mar. févr. 21, 2023 11:37 amVasttech design c'est la société qui a conçu le système de suspension.
La marque du bike c'est Veli.
https://veli.bike/index.php
Re: Vasttech design
Posté : mar. févr. 21, 2023 2:40 pm
Re: Vasttech design
Posté : mar. févr. 21, 2023 5:21 pm
c est comme une fourche Lauf , pas très heureux niveau esthétique ... mais bon pourquoi pas ?
Re: Vasttech design
Posté : mar. févr. 21, 2023 5:41 pm
A les lire,il y a pas mieux,plus simple et plus léger.
On va tous en commander un
On va tous en commander un
Re: Vasttech design
Posté : mer. févr. 22, 2023 3:40 pm
Sur la video statique du site on voit clairement le pédalier bouger à chaque impulsion sur la suspension. Il ne revient jamais en position initiale. C'est assez allucinant.
Re: Vasttech design
Posté : mer. févr. 22, 2023 4:01 pm
Oui c'est ce que je disais plus haut, du pedal kick-back et pourtant ils disent que leur système de suspension réduit l'effet de 21%.
Mais ce qui me semble le plus important, comme le disait Lafoy plus haut, c'est l'efficacité de la suspension lors du freinage arrière.
Je leur ai posé la question à ce sujet.
Mais ce qui me semble le plus important, comme le disait Lafoy plus haut, c'est l'efficacité de la suspension lors du freinage arrière.
Je leur ai posé la question à ce sujet.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 7:43 am
Système d'axe de roue arrière dédié, donc pas de possibilité de choix de roue.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 12:25 pm
Va falloir se préparer à payer cher le moyeu compatible.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 12:48 pm
Il est livré avec des roues carbone monocoque à bâtons.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 4:39 pm
D'ac mais si tu veux faire un montage à la carte.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 4:43 pm
Je ne pense pas que cela soit possible.
Il est vendu en vélo complet en édition limité.
Il est vendu en vélo complet en édition limité.
Re: Vasttech design
Posté : jeu. févr. 23, 2023 5:42 pm
Ok,ce qui m'a mis le doute c'est de le voir avec des roues à rayons.
Re: Vasttech design
Posté : ven. févr. 24, 2023 8:45 am
La réponse de Vasttech Design concernant l'efficacité de la suspension lors du freinage :
Braking affects suspension on almost all full suspension bikes. I will one day prepare some tech articles on this subject as there is plenty of theories out there that don’t always match the facts. Here’s some useful information in brief. Rear suspension response to braking can divided into two main catagories.
1: The first and most significant is the pulling force of the rear tyre against the ground when braking. This force tries to lengthen your chainstays, and occurs regardless of whether your wheel is rotating or not. A bike with a purely vertical axle travel path will feel no influence from this. A bike with a very rearward axle travel path will feel a large influence from this. With most high pivot bikes the axle travel path has some rearward direction to it right through to bottom out, so these designs will squat the most under braking. So the influence of this force is relative to how much braking traction your rear tyre can achieve, and the direction of your rear axle travel path.
2: The second significant force relates to braking on a rotating wheel and how that affects the suspension based on the leverage kinematics. You can test this with your bike in a stand. Spin the rear wheel up to speed, then slam the rear brake, and the rear suspension will compress. The amount of compression will be relative to 3 things. The rapidness of the deacceleration, the weight of the wheel, and the suspension kinematics. The compression can appear dramatic in a bike stand when you deaccelerate the wheel from very fast to complete stop in a split second. However, in real world riding to deaccelerate from full speed to a complete stop takes at least 3 seconds. If you apply that amount of braking force in the bike stand you will find the suspension compression less significant. The weight of the wheel is the second factor. If your wheel weighs nothing there will be no compression as there is no rotating kinetic force. A lightweight wheel will compress the suspension much less than a heavy wheel. So suspension response to braking is of less concern to XC riders with light wheels compared to DH riders with greater wheel mass. Thirdly the suspension kinematics: Our testing shows that the more your suspension weighs the less it responds to the braking force as there is more inertia to overcome to initiate the movement. Makes for near useless bump absorbtion properties however. Secondly, the further the main pivot point is away from the rear wheel the less the compression.
The question is, what is optimum? It is our opinion that rear suspension compression under braking should equal or be slightly more than front suspension compression. I will explain why. Imagine you are riding a steep technical downhill section and apply both brakes in the usual manner. The deacceleration will cause your fork to compress. If your rear suspension does not compress the effect will be to steepen the head tube angle (at the very moment you wish it was slacker for more stability), and shift your mass forwards (also a bad thing). If however your rear suspension compressed an equal amount to your front suspension under braking, your bikes geometry would remain stable and predictable (along with your body mass distribution over the wheels). If your rear suspension compressed more than the front, you would have a slackening head tube angle and a mass shift towards the rear. This has benefits in stabilizing the bike through a technical downhill section.
So, how does the Vasttech system perform? Regarding the first force, our rear axle travel path is rearwards for its first 50% of travel, so the braking force as it relates to tyre force on the ground exits until 50% compression, but has no effect after that. Regarding the second force: The ultra-light unsprung mass, and the proximity of our main pivot point to the rear wheel means the compression is more than most (maybe all) bikes for the effect of a deaccelerating rotating wheel, but the lightness of our wheel means this force is small.
When riding our Vasttech suspension bikes on technical trails, we find the rear suspension compression to be very near equal to, or slightly more than the compression of the fork. We get a lot of compliments on how our bikes handle tight technical terrain. Most people can’t explain all the reasons for this, but the braking response as it effects the bikes geometry is one of them. It also remains active under braking whether the wheel is in rotation or skidding under full brake lock.
Tim Southall
Director: Vasttech
Braking affects suspension on almost all full suspension bikes. I will one day prepare some tech articles on this subject as there is plenty of theories out there that don’t always match the facts. Here’s some useful information in brief. Rear suspension response to braking can divided into two main catagories.
1: The first and most significant is the pulling force of the rear tyre against the ground when braking. This force tries to lengthen your chainstays, and occurs regardless of whether your wheel is rotating or not. A bike with a purely vertical axle travel path will feel no influence from this. A bike with a very rearward axle travel path will feel a large influence from this. With most high pivot bikes the axle travel path has some rearward direction to it right through to bottom out, so these designs will squat the most under braking. So the influence of this force is relative to how much braking traction your rear tyre can achieve, and the direction of your rear axle travel path.
2: The second significant force relates to braking on a rotating wheel and how that affects the suspension based on the leverage kinematics. You can test this with your bike in a stand. Spin the rear wheel up to speed, then slam the rear brake, and the rear suspension will compress. The amount of compression will be relative to 3 things. The rapidness of the deacceleration, the weight of the wheel, and the suspension kinematics. The compression can appear dramatic in a bike stand when you deaccelerate the wheel from very fast to complete stop in a split second. However, in real world riding to deaccelerate from full speed to a complete stop takes at least 3 seconds. If you apply that amount of braking force in the bike stand you will find the suspension compression less significant. The weight of the wheel is the second factor. If your wheel weighs nothing there will be no compression as there is no rotating kinetic force. A lightweight wheel will compress the suspension much less than a heavy wheel. So suspension response to braking is of less concern to XC riders with light wheels compared to DH riders with greater wheel mass. Thirdly the suspension kinematics: Our testing shows that the more your suspension weighs the less it responds to the braking force as there is more inertia to overcome to initiate the movement. Makes for near useless bump absorbtion properties however. Secondly, the further the main pivot point is away from the rear wheel the less the compression.
The question is, what is optimum? It is our opinion that rear suspension compression under braking should equal or be slightly more than front suspension compression. I will explain why. Imagine you are riding a steep technical downhill section and apply both brakes in the usual manner. The deacceleration will cause your fork to compress. If your rear suspension does not compress the effect will be to steepen the head tube angle (at the very moment you wish it was slacker for more stability), and shift your mass forwards (also a bad thing). If however your rear suspension compressed an equal amount to your front suspension under braking, your bikes geometry would remain stable and predictable (along with your body mass distribution over the wheels). If your rear suspension compressed more than the front, you would have a slackening head tube angle and a mass shift towards the rear. This has benefits in stabilizing the bike through a technical downhill section.
So, how does the Vasttech system perform? Regarding the first force, our rear axle travel path is rearwards for its first 50% of travel, so the braking force as it relates to tyre force on the ground exits until 50% compression, but has no effect after that. Regarding the second force: The ultra-light unsprung mass, and the proximity of our main pivot point to the rear wheel means the compression is more than most (maybe all) bikes for the effect of a deaccelerating rotating wheel, but the lightness of our wheel means this force is small.
When riding our Vasttech suspension bikes on technical trails, we find the rear suspension compression to be very near equal to, or slightly more than the compression of the fork. We get a lot of compliments on how our bikes handle tight technical terrain. Most people can’t explain all the reasons for this, but the braking response as it effects the bikes geometry is one of them. It also remains active under braking whether the wheel is in rotation or skidding under full brake lock.
Tim Southall
Director: Vasttech
Re: Vasttech design
Posté : ven. févr. 24, 2023 9:13 am
Et la réponse de Veli Bike concernant la possibilité de monter des roues classiques :
Not yet. Just one wheel option available currently which is the full carbon monocoque. We are considering a traditional spoked wheel option for next year at a cheaper price point, but they don’t perform as well so we went full carbon only for this year.
Not yet. Just one wheel option available currently which is the full carbon monocoque. We are considering a traditional spoked wheel option for next year at a cheaper price point, but they don’t perform as well so we went full carbon only for this year.
Re: Vasttech design
Posté : ven. févr. 24, 2023 7:17 pm
Re: Vasttech design
Posté : ven. févr. 24, 2023 8:19 pm
Il faudra qu'ils prévoient aussi d'autres tailles car cette année une seule taille disponible.