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Shock Absorbers, Easy DIY!


mrelwood

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I finally found a combination of design and materials for EUC shock absorbers that work exceptionally well. Most if not all EUCs have a similiar pedal design in which the pedal is extended to the other side of the pivot point. This extension is stopped by the motor arms. Attaching a suitable amount of springy material between those points makes for an easy DIY shock absorbers. Doing this is safe, since if the shock absorbers fail or get detached during riding, the pedals only return to their original behaviour.

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Materials

Choosing the best materials is a bit tricky since the material thickness should compress to almost nothing. Silicone gel from shoe insoles works well for this, and restores it's form well even under these rough conditions. The gel is not perfect however, as the rebound seems to be a bit slow and weak. It also seems to be a bit bouncy in some situations. Some shoe insoles use firmer polyurethane foam that is exeptional for shock absorbing. It doesn't compress nearly as much as silicone gel, so by itself it is hard under pressure and increases the pedal angle too much.

I have tried quite a few designs and materials over the last month. Note that most pics do not show the current design.

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Result

Using PU foam and silicone gel together I was able to construct shock absorbers that work marvellously. I have no porblem riding at device max speed of 35km/h over small bumps and rough patches on dirt roads. I stay perfectly in control, as my feet stay glued to the pedals. Dirt roads are now more comfortable than asphalt, since the asphalt roads here have a lot of cracks and other inconstencies. Shock absorbers even out the cracks too ofcourse, but they don't disappear. Feet fatigue is also reduced by a significant amount. I would also like to claim that the grip between the EUC and ground is now better. I think that since the downward force from my weight to the wheel stays more uniform, the EUC bounces less. In practice I have a lot more confidence keeping up speed on steep and bumpy uphills. My average speed has increased quite a bit.

All EUCs would benefit largely from shock absorbers. Especially when riding fast, the riding control is a lot better, making riding itself safer.

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Design

The key to best operation seemed to be to put PU foam in places that won't close completely when the pedal is in riding position. There is a groove in the KS-16S motor arms that I filled with a 1 * 4cm piece of the 5mm thick PU foam. I attached a 3-4 * 10cm piece of the 5mm thick gel insole with a metal wire pushed through the ends. The KS-16S has holes through the motor arms at suitable places, so I pushed the wire through to the other side, and again through the gel. It's best to leave the fabric on the gel insole to the outside, otherwise the ends of the wire would cut through the gel.

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In the picture below is the additional bar under the gel cover. In the picture the bar is of the same gel, later replaced with the better functioning PU foam.

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Cost of the shock absorbers was in my case $0, since both insoles were deemed unsuitable for intended use. The value of the shock absorbers is a lot higher than two pairs of insoles, and I wouldn't think twice before buying them just for this.

Do note that Other EUCs might not have a design that can incorporate the shock absorbers as well, or at all. For example IPS Lhotz has such small contact area that I don't know how one would get the material to stay in place. Besides, the Lhotz pedal connection is tight, so the geared plastic hinges would have to be filed flat to loosen the joint for the suspension to work at all. And the pedal angle is already too steep...

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Cool project! I just checked what could be possible on a V8 (it may be doable). It's somewhat unfortunate that the design and possibly even the material needs to be specifically tailored to the EUC model.

Do you have a measurement or estimate of the overall suspension travel that you achieve? I am slightly less optimistic about the size of the effect that is achievable with this method, in particular on riding safety. I can't quite see how a slightly larger tire run with slightly less air pressure shouldn't be at least as effective on absorption and grip contact. That your average speed has increased quite a bit due to this modification suggests to me that it may rather have a negative effect on riding safety.

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Why not use a tube of bathroom silicone, clean up the metal on the frame and squeeze a thick bead of it along the contact point, then put some cling film or polythene on it whilst still mouldable and open the pedal to the position you want it. You've then got a custom moulded elastomer spring stuck to one side.

If you want a bit firmer material you can use a tube of polymer glue that sets to a consistency of rubber, Stixall is a good one if it's available in your country.

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5 minutes ago, Gimlet said:

Why not use a tube of bathroom silicone, clean up the metal on the frame and squeeze a thick bead of it along the contact point, then put some cling film or polythene on it whilst still mouldable and open the pedal to the position you want it. You've then got a custom moulded elastomer spring stuck to one side.

I don't think silicone caulk will take compression very well, even when fully cured. Maybe something like Shoe Goo

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1 hour ago, Mono said:

Do you have a measurement or estimate of the overall suspension travel that you achieve?

No idea. I would have to measure the center point with me standing on the EUC. All the testing was done purely by feel on the same paths with familiar rough spots and obstacles.

1 hour ago, Mono said:

I can't quite see how a slightly larger tire run with slightly less air pressure shouldn't be at least as effective on absorption and grip contact.

In order to absorb going down curbs the tire pressure had to be lowered so much that it had a negative effect in feel of control and ofcourse mileage.

1 hour ago, Mono said:

That your average speed has increased quite a bit due to this modification suggests to me that it may rather have a negative effect on riding safety.

I'm still in a bit of a honeymoon perioid with the current setup, and I decidely take on speed for rough spots just for the fun of it! I'm sure I will calm down in time... A big effect is the lack of leg fatigue. I used to be a bit worn out towards the end of my trips, so I would take curbs and bumps very slowly. Without the fatigue I know I'm sharper and more alert. 

29 minutes ago, Gimlet said:

Why not use a tube of bathroom silicone, clean up the metal on the frame and squeeze a thick bead of it along the contact point, then put some cling film or polythene on it whilst still mouldable and open the pedal to the position you want it. You've then got a custom moulded elastomer spring stuck to one side.

I did think about it, and actually the red silicone tube in one of the photos is filled with silicone. It didn't behave very well. The suitable materials and thicknesses took quite a bit of testing, so a silicone would be a lottery to get to the right thickness and riding pedal angle. And waiting for it to dry completely would mean two days without riding. Can't do that!

29 minutes ago, Gimlet said:

If you want a bit firmer material you can use a tube of polymer glue that sets to a consistency of rubber, Stixall is a good one if it's available in your country.

I found it good to have such material and amount that the weightless pedal angle is quite high. Solid rubber is way too dense for that, as it doesn't actually compress that much.

20 minutes ago, dmethvin said:

I don't think silicone caulk will take compression very well, even when fully cured. Maybe something like Shoe Goo

Or, or... Lemme think... Insoles!! How about insoles? Wouldn't have to wait for it to cure... ;o)

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6 hours ago, mrelwood said:

I found it good to have such material and amount that the weightless pedal angle is quite high. Solid rubber is way too dense for that, as it doesn't actually compress that much.

Well thats what I used when i was playing around with the idea a year or so ago!

It did work to a certain extent but I found that when I put enough in to get the amount of movement I wanted the pedals were up at too steep angle for my general comfort.

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  • 3 months later...

I used @mrelwood s idea. I took the shell- protection pads that shipped with my 16s, stuck to the pedals.  I pealed them off and stuck them where the pedal contact the hangers.  They seem to work well, hold up well, and do not tilt the pedals noticeably 

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  • 2 weeks later...
  • 1 month later...
shock absortion for pedals

im thinking for models of eucs where you cant do this trick

i have another idea. here is a little drawing im thinking of doing this

(drawing is eccagurated)  but im thinking of putting springs or rubber between the two parts of my pedal (gotway pedals)

flat part on top and hollow part on bottom 

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8 hours ago, Shad0z said:

shock absortion for pedals

im thinking for models of eucs where you cant do this trick

i have another idea. here is a little drawing im thinking of doing this

(drawing is eccagurated)  but im thinking of putting springs or rubber between the two parts of my pedal (gotway pedals)

flat part on top and hollow part on bottom 

You do that, and let us know how it works out........from your hospital bed.:facepalm:

How are you going to control your wheel when the front and back of your foot can move up and down without necessarily moving the pedal up and down? And vice versar?

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8 hours ago, Shad0z said:

shock absortion for pedals

im thinking for models of eucs where you cant do this trick

i have another idea. here is a little drawing im thinking of doing this

(drawing is eccagurated)  but im thinking of putting springs or rubber between the two parts of my pedal (gotway pedals)

flat part on top and hollow part on bottom 

There already on the market. Some idiot tried them out on an ACM and crashed! 

26963574678_fcabe89d96_b.jpg

 

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4 hours ago, Smoother said:

You do that, and let us know how it works out........from your hospital bed.:facepalm:

How are you going to control your wheel when the front and back of your foot can move up and down without necessarily moving the pedal up and down? And vice versar?

im thinking about either springs or rubber but my main choice would probably be rubber and as i said

"over eccaguration" and im thinking 1 cm or less

i will try see how it works out. im not expecting this to work that well but i will give it a go anyways doesnt hurt to try

 

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8 hours ago, Shad0z said:

im thinking about either springs or rubber but my main choice would probably be rubber and as i said

"over eccaguration" and im thinking 1 cm or less

i will try see how it works out. im not expecting this to work that well but i will give it a go anyways doesnt hurt to try

 

It would probably be easier to just get a pair of soft spongy shoes, or insoles.

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21 hours ago, Shad0z said:

i will try see how it works out. im not expecting this to work that well but i will give it a go anyways doesnt hurt to try

Ask @Rehab1 if it hurts to try...

As for suspension, @Joey Serrin's MAX wheel as it "integrated" check out his video...

 

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8 hours ago, The Fat Unicyclist said:

Ask @Rehab1 if it hurts to try...

As for suspension, @Joey Serrin's MAX wheel as it "integrated" check out his video...

 

as for try i mean not while the pedals are attached

i have seen that max euc and thinking about that it could be nice to make one myself. but my problem is materials and skills

and just not wanting to risk anything and just be happy with what i have

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2 hours ago, Shad0z said:

oh i just noticed somewhere on youtube another guy did the same thing that i was thinking of doing on his ks pedals so atlest it would be possible to a small extend

Um, Hello! Where's the link?

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