Suspension in the wheel

[Preytec]

Hi,

I know this is my 1st post, But I never needed to post as I'd do a search and someone has already posted the answer, which is great, so thanks guys.

As it stands, I'm riding my 2nd build and I've got my 3rd picked out and I should be ready to put it together after xmass.

But one thing annoys me, the suspension. I've got a 1000w 48v mp4 so I do need good suspension front and back. the front is fine. But the back takes a lot of room from the inner frame. I'd love to use a bike with only front sub, leaving loads of room in the frame for a bottle battery.

Does anyone know if there is even talk about having suspension in the wheels sometime down the line.
here are a few pic's so you have a better understanding of what I mean



Now I don't think that those wheels would be good enough for a ebike, But maybe a ramped up version?

I found this post but I'd like to see if anyone has any updated info on it? http://goldenmotor.com/SMF/index.php?topic=4899.msg28595#msg28595

Thank you.

[Morgen 3Eman]

Hi,

My first thought is that a chassis based suspension deflects when a  whole bike load condition changes, like when you hit a bump, or jump a curb.   The wheel based suspension deflects every degree of rotation of the tire, whether the total system load changes or not, as the hub will always be displaced from the center of the tire rotation by the static gravity load.

Side loads may also cause the tire and hub axis of rotation to precess, as well.   

What benefits are claimed for the designs?  They certainly look distinctive!

TTFN,
Dennis

 

[Preytec]

Hi Dennis,

They Both claim the same things, that you don't need built-in suspension and that you can fit their wheels and have full suspension.

I believe they were first planned for wheelchairs but then moved on and worked towards pushbikes.

The loopwheel looks like it could be designed to fit with a mp4 if it was a little smaller and more loops, the Softwheel looks a bit... humm...soft? TBH.

would having the hub displaced from the center be a big issue? would it case too much stress on the suspension and cause it to fail prematurely?

[Morgen 3Eman]

Hi,

They would both seem to work to soak up shock loads from bumps and things,  and that would be useful for wheel chairs. 

The reason I'm suspicious of the hub/wheel miscentering is that it seem you would always have to overcome the energy losses of displacing the wheel about the hub as it rotates, like you would always be peddling uphill to some degree. 

TTFN,
Dennis

[e-lmer]

Relevant
https://www.youtube.com/watch?v=PPKY1pFyqu8

[Preytec]

Cheers for that e-lmer.

I think that vid highlighted Morgen 3Eman's point.
That guy looked like he was trying very hard to pedal at one point, in fact they didn't show much of the wheel really.

[AdamB]

In fairness, I have no financial stake in this product but I do have intellectual stake in wheel innovation... But this is the 1st time I have ever heard of said product...

My 1st thought is interesting but I see problematic areas... Most importantly (having extensively studied suspension systems) is that it may help in the area of high frequency vibrations but will likely do nothing for the low frequency vibrations... As such will likely not be able to wholly replace proper traditional suspension...

Polymer based suspensions typically handle high frequencies well but are not good for low frequency... This means that if you are content with traditional polymer fork suspensions, then you will probably like the product.

However if you require traditional spring (among other types) suspensions, you'll probably find the product woefully inadequate! It's my personal opinion (& requirements) that I need both types to create an effective suspension system for my needs.

I will say that it may pair well with other types of suspension! Also I watched the videos & I agree that it seems more difficult to pedal, but no more so then is comparable to other small wheeled bikes... So I don't think all of the visible difficulty can be blamed on the novel suspension method.

I also agree that this style is useless for our purposes but I think that if we used far smaller versions, that say replaced the spokes 1:1 or 1:2 would probably work for us & maybe even fix some of the other issues! Specifically, by multiplying the amount of springs supporting any given point, will probably ensure that the wheel remains true/straight/level/balanced throughout. Though it also may not work, it's hard to say without a lot of prototyping & study...

It's important to remember that although its not readily obvious, spokes are actually behaviorally akin to springs!

Definitely interesting, especially that it was initially designed for mobility devices who's disabled users frequently suffer vibrational injuries as a result of the device utilized!

Thanks for sharing! It definitely got the old cogs in my head spinning

Adam

[Supchrgamx]

see it working fine strait up cant see it working at a 45 deg. angle very well
Laurence

[AdamB]

Ummm, maybe I'm not getting it but why would anyone run any wheel at  45 degrees? I'm as big a fan of camber as anyone but I'ld never run anything THAT high! Max I would do is 10-11 degrees & that's considered really high!!!

[Supchrgamx]

I turn corners so hard I scrape pedals and I think 45 deg is conservative
Laurence

[Bikemad]

If it was a front wheel on a three wheeler I might agree with you, but as bike leans into a corner, the majority of the force should be angled directly through the centreline of the wheel.

Those wheels probably will not be much good for this sort of application:



If the wheel could withstand the lateral load without failure,  the lateral movement would provide sideways suspension in addition to the vertical suspension to help the tyre stay in contact with the road whilst cornering on an undulating surface.

Alan
 

[Morgen 3Eman]

Thanks for the photo and the laugh, Alan.

Adam, you are right about wire spokes being springs, but the spring rates are so high, and the deflection so small in use that the spring effect would be essentially zero. 

As a fan of three wheelers, the effects of side loads are important to me.  I often corner on two wheels with my Morgen ( !    )  and the deflection of the rim about the hub is very noticeable.  When I lean over the side in corners to keep all the wheels on the ground it is also noticeable on the inner wheel.  To be fair, these are wide bike rims with thick spokes, not motorcycle wheels. 

I think Michellen was making some poly wheel/solid tire products a few years ago, but their  curved version of the spoke was very wide across the hub and rim, and would probably eliminate that deflection effect.

TTFN,
Dennis

[AdamB]

Sorry, my bad... I was not thinking clearly... If I had, I'ld have realized what he meant. I had a rough night; The guests I invited for the night, locked me out of my house & I was very angry. I guess I wasn't thinking clearly!

In terms of springs, spokes, etc; I wasn't saying they're equivalent. Just that often in discussing why bike wheels are built in "x" manner, people don't understand that the whole point is creating that spring effect & is the reason for the limitation of thickness of the spokes.

While you can get sufficiently high tension with thicker spokes in some applications (ex. motorcycle tires), in most bike applications you can't & instead of a stronger wheel, it ends in a weaker wheel through insufficient tension for "x" spoke size & no spring effect.

I've noticed that confusion is common in the e-bike community, who often think that they can use thicker spokes at the same tension as thinner & accomplish stronger wheels!

I mentioned it as it seemed to be the likely inspiration behind this wheel design in this post & why it may be more effective then at 1st blush (assuming forces are distributed more evenly).

Anyways, sorry for the confusion!

Adam