Kingsong S18. Rebuilding the suspension.

Today I will tell you how I rebuilt the suspension on the wheel from the first batch. Perhaps, the manufacturer will introduce some changes and improvements to the next batches. Therefore some parts may be different in the future.
I will not dwell on disassembling the wheel in detail. If you have any questions, watch the video from Kingsong.
After removing the top cover, we will need to remove the cover of the controller and disconnect the terminals from the battery. Then press the power button to discharge the capacitors.

Then we disconnect the engine.

Unscrew the batteries.

We unscrew what Kingsong calls the “battery base” (and I call them “underpants”) by undoing the four screws in the base one by one. Remove this base and the battery packs.

Remove the wires.

Bleed the tire and pull out the engine.

Then we remove the mud protector.

And now we can go on to disassemble the suspension. First we unscrew the axles of the shock absorber.

Very carefully undo the screws securing the links (golden frames). The metal is soft, so you might tear down the slots.

Remove two pairs of links. And we also uncouple them to release all the bearings.

Then we squeeze out the bearings. A screw with a head slightly wider than 10mm will do the trick. After they were squeezed out the bearings are considered damaged and shall be replaced with new ones.

Some bearings break during the process.

The seats should be cleaned.

You can use an electric engraver complete with different nozzles. Or you can take a knife, cut through the metal runs and strip them with a screwdriver.

It’ both labor- and time-consuming. After removing the aluminum and paint runs, it is necessary to sand the seating hole to make it smoother and remove the paint. The central holes should be sanded so that the new bearings are not pinched when they rotate.

The seat at the edge of the link should not be sanded too hard, otherwise the bearings will not be properly press-fit and will fall out.
We install in new bearings in the seats. We use 19x10x5 bearings. (Types 61800 2RS, or 6800 2RS, or 6800 VRS). I found the Craft bearings here. We need 14 bearings, the load on them is not significant, so I don’t think that you need some expensive and branded bearings.

The bearings were press-fit using a homemade press based on a hydraulic jack, a metal platform and a socket of suitable size(19mm). This is very important, because the bearing must be press-fit precisely along the outer race, without creating pressure on the inner race. Otherwise, the bearing will be damaged and you will have to replace it. A long bolt or stud with two nuts and a set of washers of different diameters and sizes can be used instead of a jack. The pressing force shall not be too high, otherwise the bearings will wedge up. If the bearings do not move smoothly, you will need to sand the seating hole a little more.
By the way, I recommend treating it with neutral grease (silicone grease is the best choice) so that the bearing wouldn’t eventually turn sour in the link. Steel paired with aluminum often causes such effect.

After press-fitting of each of bearings, I recommend that you check how the links swing on them. You need 14 pcs., but I advise to buy 20 bearings in case some of them get damaged during press-fitting. It is not good to put excessive pressure on the bearings, since you squeeze them out over the inner ring, which creates excessive pressure, distortion and pinched balls. Such bearings will be then unfit.

The next step is to check the axle and sliders (grey iron parts of the suspension, otherwise “pants”). First, make sure that your axle has strictly parallel mounting cuts and does not narrow to the edge. Then fix the sliders tightly on the axles as usual.

Make sure that the sliders stand exactly parallel.

Check how the upper base pipes (with the controller, called also “legs”) move in the sliders.

Pipes should move well and smoothly. Watch the gaps. If there are problems with movement, then check the deviation. Find out which slider deviates and at what angle.

After that you should carefully widen the groove to fit the axles on the slider. Some sliders are supplied with a groove. Some are not. It is also possible that there will be a metal plate between the axles and the groove of the slider. Moving forward a little, it helps to align the engine in the arch so that it stands upward.
After widening, we fix the slider again on the axles with inserted pipes and, by tightening 4 screws each at 1/6 turn, control the vertical position of the slider at all times while moving the pipes so that they are not pinched. You may need several goes at this. The milling machine is not at everyone’s fingertips, so you need a good file and vice clamps, so that the pipes move in the right plane as closely as possible. Otherwise, you may easily damage the part. Fitting of sliders to the axles is also a very labour- and time-consuming process. But not all wheels require such fitting. Sometimes, sliders from the factory are quite well fitted.
On the photo above note that when clamping the axles the lower finger can also clamp the plastic axle boots. If they are squeezed, they start to press on the pipes and don’t let them move either. These boots need to be carefully worked on with a needle file to create small indentations so that the finger no longer presses on the boots.

The next step is to install links. You will need bushings to assemble everything correctly. It would be best to make them out of nylon. But, unfortunately, the details of different wheels significantly very in sizes and it will be very difficult to pick the required size. So I decided to just buy a sheet of fluoroplastic and with quite simple set of punches make the necessary washers that would replace the bushings. The washers must be as thin as possible to be able to connect each pair of links. You can take a sheet of fluoroplastic and flatten it with a heated iron or press to make the washers. It is better to stain the washer first, and then flatten it. It will be easier and more efficient. Washer size: 14×10. From personal experience, I can say that it is most convenient to work with a 2 mm thick sheet.

Then we install the thin washer between the links. Don’t worry if it turns out not too neat. We just need to separate the outer races of the mating bearings. There will be no significant load on the washer.

The length of the axles is 22mm, it holds 4 bearings on it, i.e. 20mm plus a flattened washer about 0.2mm thick. We add another 2mm washer so that the details are not slack. Screw in the axle screw (with a drop of threadlocker) until it stops. We check how one link swings on the other.

Now you have to fix the link in the upper base loop (where the controller is). We will need to install 2 washers (4mm) twice here. We take the axles, and string two washers. Then we run the axle through the bearing and add 2 more washers.

And now we insert it into the loop.

Drop a dab of the threadlocker on the screw and screw it until it stops.

But here you need to avoid tension and check that the axles do not start to compress our fluoroplastic washers.

We check how our links work. They should move smoothly.

Before you proceed, carefully wipe and degrease the pipes to keep them clean. Apply a little silicone grease and dry thoroughly with a clean microfiber cloth. This way, we obtain a thin almost dry layer of lubricant on the pipes so that as little dust as possible adheres to them. Slider sleeves can be additionally sprayed with dry PTFE based lubricant (Teflon grease). Now we put the sliders on the pipes to fix the bottom links.

Again we take the axle and 3 washers to obtain 6mm.

We insert the axles into the bearings of the link, and we string the washers on the other end.

After that we insert it into the loop of the slider.

This is what we get.

Then we fix the screw with the applied threadlocker.

We check the links. Sliders should move smoothly and without resistance. Then we connect the links and the axes from the shock absorber and installed spacer bushings, but we don’t install the shock absorber. We check the movement again.

We put the mud protector back in place.

We put the engine back.

And fix the axles to the sliders. And check again. Sliders should move freely on pipes.

Now, we proceed to the so-called “battery base” (underpants). Here I will allow myself a little distraction.

I want to show you how the battery is arranged inside.

The small one first. It consists of 10 cells connected in series. The charging voltage of the unit: 42V (rated voltage 36V).

The unit is placed in an aluminum profile, under the CEM we see a complete BMS unit.

LG M50T cells.

The large unit with charging voltage of 84V.

Plastic holder for cells.

The BMS board serves as a mounting base for the battery cells. There are 20 of them.

This is the inside the aluminum profile of the battery.

BMS is a bit bigger. There are no fuses here. A whole lot of transistors provide protection of the unit, including protection from the short-circuit as well. I don’t really know how this all works.

I also did not pick the battery open to find the temperature sensor. I hope it is there somewhere.

When assembling the wheel back, the batteries often start rubbing against the mud protector.

I suggest using these spacers when attaching the battery to minimize rubbing. This is a pair of washers, which will give a little spacing.

The second thing is that when tightening the fixing screws you must use aluminum bar, which comes with the wheel.

The bar allows you to correctly orient battery units and prevent possible distortion. The main thing is not to forget to knock out this bar later, otherwise the suspension will not work as intended.

Screw the batteries so that they do not contact the sliders.

Again, we check how everything works. Then we connect the batteries, complete the assembly of the wheel.

At the very end, we remove the axles for the shock absorber. Don’t forget to treat one of the bushings, which is wedged in the loop of the shock absorber. You can just sand it so it rotates normally during installation. It is convenient to clamp it on the axles, put it in the screwdriver and simply rotate it against the sandpaper.
Then we polish it a little. Do not forget to grease both bushings and install the shock absorber.

We pump the main space up to about 150psi so that the suspension is fully straightened. We pump the lower space to 50-60psi. Install the plastic bar for pumping, pump the main space to fit your weight. Once again check how the suspension works and you are free to ride. It’s ready now.

Leave a Reply

Your email address will not be published.