Kingsong S20/S22 (Confirmed)

[Paul A]

The more interesting aspect is how well it works.

The open configuration seems to allow any dirt to freely enter and exit.  Rather than trying to prevent ingress.

 

[Paul A]

Perhaps the S20 slider blocks could adopt the vertical ridges.

Reduction of contact area.

Reduction of grit embedding.

Grooves to allow movement of air flow, dirt/grit exit, drainage, evaporation, corrosion resistance, etc.

 

[Eucner]

1 hour ago, Paul A said:

The open configuration seems to allow any dirt to freely enter and exit.  Rather than trying to prevent ingress.

Unprotected design is never good for dirty environment. You really don't want to have dirt between moving parts.

1 hour ago, Paul A said:

Perhaps the S20 slider blocks could adopt the vertical ridges.

Ridges and recesses would benefit sliders.

I checked two igus design tools. Their sliding bearings material could last about few hundred hours in the clean S20 suspension rails.

[Paul A]

Would be interesting if there were experiments to try and deliberately have dirt/grit adhere to the surfaces.

Would the dry surfaces be so slippery that dirt/grit would not adhere?

Probably would eventually wear out, but hopefully much longer lifespan, and maintenance free.

 

Video of Igus bearings.

 

[mrelwood]

Linear bearings are generally made for 3D printers, and their weight/pressure handling is really low. I would think that the fixed sliding igus bushes are much better, but I don’t know if the material itself is rigid enough for the pressures required in an EUC suspension.

[enaon]

anybody knows what the material on the s18 is? I did't give it much notice when I looked at it, but is seemed some kind of plastic too. In this case(not my s18) the slider was moved a bit due to friction/debris. 

 

Edited March 13, 2022 by enaon

[OldFartRides]

Just looking at it I thought it was a cheap steel bushing, but I didn’t check it w/ a magnet when I had them apart.

 I too would like to know now.

Edit: rehab or fbhb would probably know…

Edited March 13, 2022 by OldFartRides

[Eucner]

Looks like a plastic sleeve in aluminium tube.

[OldFartRides]

The grey sliders are  steel I believe. I know they’re not aluminum.

[Eucner]

2 minutes ago, OldFartRides said:

The grey sliders are  steel I believe. I know they’re not aluminum.

Inside the grey structure is an aluminium tube and inside it is a plastic sleeve. The tube and sleeve are bonded together, I assume.

[enaon]

10 minutes ago, Eucner said:

Looks like a plastic sleeve in aluminium tube.

this is what I thought about it too from what I recall, but now I am curious. 

[enaon]

13 minutes ago, Eucner said:

he grey structure is an aluminium tube and inside it is a pl

it is not a long tube, it ισ two rings or about 2cm width, one at bottom one at top, the rod does not touch the middle section of the housing at all, it is ~1mm wider. 

 

this is why I recommend silicon spray for the s18, it has room to hold oil/debris, silicon helps keep it clean. 

Edited March 13, 2022 by enaon

[Eucner]

15 minutes ago, enaon said:

one at bottom one at top

Sounds like a standard configuration for bearings.

[Planemo]

I imagine they are very similar to what is found in MTB forks - a bushing with a steel outer and a PTFE/DU/plastic of some sort liner.

Rock Shox Bushing Kit Domain/Lyrik, 114015065000 : Amazon.co.uk: Sports & Outdoors

Edit: FWIW, the S18 telescopic fork solution is by far the best I have seen in EUC's so far. I just cant understand what KS were thinking with the 'exposed-plastic-slider-running-in-aluminium-channel' setup in the S20. I guess it's lighter but IMO it's poor. Very poor.

 

Edited March 13, 2022 by Planemo

[techyiam]

Just from casual observations, it does appear that for suspension systems on motor vehicles, bearings running on rolling friction elements use grease, and bearings running on sliding friction elements  (bushings) are in an oil bath (except on bicycle rear suspension pivot joints that have very small rotational movements). Suspension pivot joints and forks are prime examples. In addition, they are in a sealed, closed system, even if the vehicle is designated as for on-road use. I suspect only the cheapest of the cheap forks on really cheap bikes don't use oil in them. But the internals still are not exposed to the elements. Only euc's can go lower.

Still, suspension helps, and let you go faster on bumpy roads, albeit being primitive, has short operating life, and requires frequent servicing. As @Tawpie said in another post, we are a long long ways off from where it will be on par with the other motor vehicles. For how much longer is anyone's guess.

Edited March 14, 2022 by techyiam

[Jon Stern]

7 hours ago, mrelwood said:

Linear bearings are generally made for 3D printers, and their weight/pressure handling is really low. I would think that the fixed sliding igus bushes are much better, but I don’t know if the material itself is rigid enough for the pressures required in an EUC suspension.

People tried igus bearings in 3D printers some years ago. They were not a better solution than conventional linear rails.

Different uses cases have different requirements though. 3D printers don't have high loads.

[spitfire1337]

Just thinking out loud here, but since the gap between the top plastic slide and bottom is a fixed space and doesn't change. Couldn't we make an insert from ptfe/uhmw etc to fit between those and prevent debris from entering between the 2 plastic sliders and still slode along the rails with the suspension?

[fbhb]

7 hours ago, OldFartRides said:

Just looking at it I thought it was a cheap steel bushing, but I didn’t check it w/ a magnet when I had them apart.

 I too would like to know now.

Edit: rehab or fbhb would probably know…

I did not actually inspect the bushings myself during my overhaul to check the material used, as I already believed them to possibly be a cheap bronze alloy bush from what was stated by Russian owners that went as far as replacing them in their S18's.

I've managed to track down a couple of photos from what I remembered seeing at the time, which show the Originals removed and the Replacement "low friction" material (No clarification on exactly what material used sorry) bushes this Russian engineer used instead:

 

 

Edited March 14, 2022 by fbhb

[enaon]

nice info fbhb.

Have you also noticed the difference on the bms's used on s18?. I have seen batches 2 to latest, all have a bms like the one on the first photo,  but I have seen on ecodrif and other Russians one that looks like it has an mcu on it (second poto). Do you have any info on this?

 

 

[techyiam]

35 minutes ago, spitfire1337 said:

Just thinking out loud here, but since the gap between the top plastic slide and bottom is a fixed space and doesn't change. Couldn't we make an insert from ptfe/uhmw etc to fit between those and prevent debris from entering between the 2 plastic sliders and still slode along the rails with the suspension?

Assuming I understand you correctly, what you are suggesting is equivalent to running the plastic bearing material for the full length of the rail. At least then, only the portions of the slide that stick out past the rails would be exposed to the elements. Normally, they don't run the bearing material for the full length of the rail to reduce stiction. But in the S20's case, it could be good idea especially if you keep the tolerances of the bearing material for the middle portions of the rail less tight in order to minimize stiction, but still keep the debris out, not unlike the concept of dust seals for ball bearings.

 

[fbhb]

26 minutes ago, enaon said:

Have you also noticed the difference on the bms's used on s18?.

Sorry, I'm unable to comment on any differences re: S18 BMS versions.

I do remember reading somewhere, that different 21700 batteries have been seen in some S18 batches, so maybe that was when the change happened?

Only a theory/guesswork though unfortunately!

[enaon]

5 minutes ago, fbhb said:

I do remember reading somewhere, that different 21700 batteries have been seen in some S18 batches, so maybe that was when the change happened?

 

batteries seem unrelated, I have seen the samsung and the lg ones on the same bms type, thank you and sorry for the offtopic. 

Edited March 14, 2022 by enaon

[Eucner]

3 hours ago, spitfire1337 said:

Just thinking out loud here, but since the gap between the top plastic slide and bottom is a fixed space and doesn't change. Couldn't we make an insert from ptfe/uhmw etc to fit between those and prevent debris from entering between the 2 plastic sliders and still slode along the rails with the suspension?

Yes. The insert should cover the groove opening, but not contact the groove on any other sides.

Unfortunately there is only minor fixes for a major problem. The suspensions system needs full redesign. At least the fender should cover groove opening.

[Curt8892]

Are there any benefits of this suspension design that anyone of you can point out? I cannot believe that the engineers in China are that stupid to change a previous design to a new one without any benefits. 

Glass half full approach.

 

[Rawnei]

3 minutes ago, Curt8892 said:

Are there any benefits of this suspension design that anyone of you can point out? I cannot believe that the engineers in China are that stupid to change a previous design to a new one without any benefits. 

Glass half full approach.

 

Less space, weight and complexity.