Craziest Bike or Bike Parts!!

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Craziest Bike or Bike Parts!!
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Posted: Feb 14, 2020 at 17:09 Quote
sherbet wrote:
Seven THOUSAND dollar hubset. Tested at 100km/h for 100,000km, as well as shorter tests up to 300km/h. Uses a dual shell design to allow some system flex for fatigue strength and compliance. Company normally makes bearings and parts for jet turbines.


Alloy hubshell models start at 3k.

pshhhh all that money and you still have to use peasant grade j-bend spokes

Posted: Feb 17, 2020 at 16:11 Quote
Interessting idea about the dual front suspension for DH bikes,since the guy has done dual front suspension for motorcycles but now he has made a MTB version of his invention.


More info on his Facebook page
https://www.facebook.com/Suspensionsmith/

Posted: Feb 17, 2020 at 21:17 Quote
The kooks would often suggest this to me when I was designing front linkage bikes that may have recently appeared on the front page. They appeared to advocate it simply from a "more is more" perspective. It's not something I pursued, as I feel it will be the worst of both worlds with all the complexity and components of both.

The advantage, which I don't recall the wacky folks every realizing, is it it allows an axle "space", rather than axle path, which could be a better way to handle both head-on and slap-down impacts via variable axle paths. The theory is sound, but a linkage system can offer such a high quality of travel and such low friction that I can't see the a second system adding enough performance to be worth the complexity.

Another concern is the lack of predictability of the system. Without a defined axle path, the steering and weight transfer behaviours would be difficult to predict. Predictability is the foundation of any high-performance system.

Posted: Mar 28, 2020 at 19:04 Quote
Heres the latest build on the previous bike pictured...this is my build by the way......a work in progress...
.
Latest build of a new prototype Dual front suspension DH bike.

Posted: Mar 28, 2020 at 19:37 Quote
Suspensionsmith wrote:
Heres the latest build on the previous bike pictured...this is my build by the way......a work in progress...

Love what you're doing. Would be interested to hear more about the variables you're exploring, where you feel the project has most potential to improve on existing systems, future investigations, etc.

Posted: Mar 29, 2020 at 1:06 Quote
R-M-R wrote:
Suspensionsmith wrote:
Heres the latest build on the previous bike pictured...this is my build by the way......a work in progress...

Love what you're doing. Would be interested to hear more about the variables you're exploring, where you feel the project has most potential to improve on existing systems, future investigations, etc.

No problem...will post up a general overview of what/why etc of this shortly....

Posted: Mar 29, 2020 at 2:34 Quote
Suspensionsmith wrote:
No problem...will post up a general overview of what/why etc of this shortly....

tup

Posted: Mar 29, 2020 at 16:49 Quote
Bare with me on this....I am trying to describe a very complex inter arrangement in a coherent fashion that makes sense too others...there may be the odd mistake that I will correct or rearrange as I go along.

Ok so what we have here is a front suspension system designed around improving on current front fork setup as we know it....teleforks are very highly refined now and work very well and they give the right kind of geometry and geometry changes to give a good handling and steering bike....and these traits are also what we as riders are used to riding.

This design keeps the telefork and its typical feel for the most part...teleforks aint perfect and this design aims to keep the pros and reduce the cons.

This design also uses a linkage suspension in concert with the telefork...in this case a Hossack/Fior type design....the linkage on top of the Telefork.
The Telefork is 200mm travel and is unchanged internally for now....the secondary link suspension gives 70mm travel....so 270mm total. and is actuating that spring/damper mounted internally in the frame.

What this now gives is a system that gives two distinct wheel paths too the front wheel....but working together...and as the suspension systems are separate they can be each tuned to give quite different characteristics in terms of wheel rate and damping rates...preload etc etc.

What this gives is a much greater range of tuning variables and combinations so allowing the tuner a greater scope for fine tuning one aspect with less compromise or effect on another aspect of suspension performance.

As an example would be the ability to setup the Tekeforks for very good small bump sensitivity and a more Linear spring force curve through the stroke as its not being asked to provide so much bottoming control.......then using the much stiffer secondary suspension to control big hits and bottoming....they can each be changed and adjusted with lesser effect on each other...less compromise.

Back to wheelpath.....the telefork is mounted as you see it at 22.5 degree at rest...so the wheelpath for the tekefork is a steep 22.5 degrees...the thing with teleforks is they tend to work better at steeper angles...less side loading on the bushes and the steeper angle means their wheel rate is less for a given internal spring rate......the same can be said for stiction and friction....this is lesser at the wheel at the steeper angles.
What this gives is a much better small bump sensitivity....what it also gives is a Telefork which is less prodive under brakes and less pitch sensitive in general....
The negative side of this steeper fork angle is less sensitivity too larger bumps and trail obstacles...it is great at absorbing the more vertical force component of a bump but it is less able to absorb the rearward force component of a bump...so its harsher on larger and more square edged bumps.
This is where the secondary suspension comes into play...it has a wheelpath which initially in the first part of travel moves back at a 45 degree angle and then curves into a more vertical path.
This means the secondary suspension is able to absorb the rearward bump force component that the Telefork cant.....so a much better overall suspension able to better deal with a greater range of conditions and extremes.

Where these two systems further work together is if you look at it this way.....the front wheel hits a larger say square edged bump....the Telefork is moving in response in the vertical and so is able to do a better job of getting the wheel up the face of the bump and over the bump and down the other side but is better able to also track the back side of the bump and so give improved overall traction ad trail holding.........also the bump is imparting less vertical accelerations into the bike...the secondary suspension is moving back at 45 degrees in response to this bump...it is absorbing the rearward force component so less rearward accelarations are being imparted into the bike...this should in turn less effect the forward momentum of the bike...allowing it to better get over larger bumps or a series of larger bumps.
The problem with having a rearward wheel path like this means is it is very prodive when braking...cant be helped really but is offset by the fact that the wheelpath is a curve so it curves into a more vertical path so is much less prodive later in the travel...also the secondary suspension is generally setup with much higher spring and damping rates than is usual...so is better able to resist load transfer and prodive when braking.

Now a bit on its steering geometry...which is also quite innovative.....

Now in the pics you will notice the forks are mounted quite steep for a DH bike....22.5 degrees in this case...but which is adjustable via the top rodend on the top link...so it has adjustable steering angle or axis.
Where it further differs here is that the forks are not mounted in line with the steering axis as is typical in most normal telefork setups....this mounts the fork at a 4.2 degree angle too the steering axis....so the fork is mounted at 22.5 degrees but the steering angle is 26.7 degrees......so why this offset differing angle...well it makes making a set of triple clamps way more difficult...so it had better be worth it hey.....what it gives is a change in wheel too steering axis offset as the fork moves through its stroke...and thus a change in trail at the ground....so we are seeing a greater variation in trail with suspension movement...trail change now isnt only dependent on the variation in pitch of the bike and steering angle too the ground....so I can build a bike which is less pitch sensitive yet still has good steering characteristics in relation to trail.
What this means is now I can set the trail up so that when the bike is sitting at level ride height it has a high amount of trail for good overall stability...good on a DH bike....but when the bike starts to pitch forward say when pointing down a steep section or braking into a corner there will be a greater change or lessening of trail...this helps to give good steering feel ...so the steering remains light and turns well when you need it to.

Whew!! To be continued

Posted: Mar 30, 2020 at 18:26 Quote
Suspensionsmith,

Thank you for the discussion! Please let me know if this is an accurate summary:

• Telescoping element is more vertical for better ground tracking and less bushing bind.
• Linkage element introduces more rearward axle path for larger impacts when the force vector is aligned as such.
• Dive forces reduced, relative to a typical telescoping configuration, especially deeper in the travel.
• Greater change in trail than a typical telescoping configuration.
• Less trail at full bump than a typical telescoping configuration.

Can you please further discuss the desire to have a greater change in trail and your thoughts on the benefit of reduced trail near full bump?

Thanks!

Posted: Mar 30, 2020 at 22:44 Quote
Yep thats a good overall summary of what I have said so far.....

Trail...thats a very interesting subject hey as I think its still not established what is the best approach to take in certain circumstances.
If we look at most bike configurations we see them using Telescopic forks....and its for a good reason....one good reason is Telescopic forks steer quite well...my own experiences building and testing various other configurations of front suspension and seeing also whats happening elsewhere in the world has shown me that a link front suspension although they can be superior in a number of different ways to a telescopic fork...usually has trouble steering as well as a telescopic fork...I think its a major reason why in two wheel sport.... alternatives to telescopic forks...and there have been many ...dont seem to get anywhere...my own experiences show this exactly...a lot of effort has to go into getting a link type suspension to steer as well as telescopic fork.....and its usually a trade off between high speed stability and good steering feel in the turns...its a greater compromise.
So why is this...what is a telescopic fork doing to make it steer so well.
The main thing about a telescipic fork is it is very prodive due to its angle...so is pitch sensitive...it also reduces wheelbase.....this is good in terms of steering because it enhances load transfer onto the front tire and it reduces trail with the steepening of the steering angle.
The load transfer is good....it aids in increasing front tire grip for maximum braking or cornering effort and the trail reduction helps to keep the steering light and precise as the bike is being steered into or through the corner while it still has a high front tire loading.
Ok so whats happening here?
When most people think of trail they think in terms of a number...the higher the number the greater the trail and the greater the associated stability it gives to the steering...the lower the number the lower the stability.
But the amount of trail is only half of the equation....
The other half is load...or "load on the front tire"
In simple terms trail and load and the associated stability it gives too the steering can be expressed as............................... TRAIL x LOAD = STABILITY.
So when the tire is in a high load situation it needs less trail to maintain steering stability....like when braking or loaded up in a corner....when the tire is in a low load situation it needs more trail to maintain stability.
When the suspension is at full bump the tire is in a very high load situation...its also a momentary situation...so the steering doesnt need a lot of trail to maintain stability.
What I am doing or looking for with my suspension and steering geometry is not so much have a low level of trail when the suspension is deep into its travel but have a better balance of trail through all the travel and have the right amount of trail.
For instance at ride height I can have a higher trail figure that gives very good steering stability at speed over rough ground...a conventional bike with this amount would pay the price of then having slow steering for the turns because it doesnt reduce its trail going into the corner enough...my bike with the changing offset changes its trail to a greater degree and so gets a lighter more nimble steering when needed...the harder I push ( load ) the front into the turn the more travel it uses and the greater the reduction of trail to maintain good steering feel.
Thats the theory anyway...I know this works in motorcycle roadracing and works very well and I have had good results using it in a 450 MX bike....MTB's are a quite different animal and so this may not be so applicable...only one way to find out..build it and ride it.

Posted: Mar 31, 2020 at 9:52 Quote
That is a real great idea, if it works that is. I'd love to have such a bike for traveling.
Imagine a foldable bike with regular gears, regular spares, and so forth, counting out the wheels.
Anyone seen one in reality?

Magura Smile

EDIT:

Just did a bit of googling. Seems it's currently just a prototype, and they expect to start an attempt at crowdfunding in September this year.
Also, it says foam tires, so while having the potential to be a proper bike, that could be used for longer distances, than the current 16-20" wheeled bikes, rolling resistance and lack of comfort is probably gonna throw a spanner in the works. Frown

Posted: Mar 31, 2020 at 13:37 Quote
noisette wrote:
Transrollers?
An accident in disguise....
Only playing.


 
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