These dampers/shocks have been discussed a few times before on this forum, but it was mostly in passing with members saying that they were good and performed well. But no other real specifics were detailed, including how they were designed, assembled or compared to the vintage Kyosho Gold shocks (W-5001 and W-5002), which these attempt to replicate.
Today I was working on rebuilding a vintage Kyosho Optima and since I had a Turbo Optima body already painted and decaled thanks to a recent eBay purchase, I decided to use these Xtra Speed dampers instead of the vintage red (10mm diameter) stock dampers in order to make it more into a Turbo Optima. I figured I might as well take some pictures to show how these dampers are assembled and comment on how they are similar and different to the original Kyosho Golds. I do not have any side-by-side comparisons between these Xtra Speed dampers and the original Kyosho Gold shocks in these pictures today, but those of you familiar with the original Kyosho Golds will recognize many aspects of the design and appreciate the similarities and differences.
First of all, what am I talking about? What are these Xtra Speed Dampers? Here is a picture of the front and rear damper sets as they are packaged and sold. They come in a white-backed plastic resealable bag with top card stapled on. The front kit is part #XS-OM27001 and the rear kit is part #XS-OM27002:
I'm going to focus on the front shock set only in this post since they are what I have built so far. Opening up the front shocks and laying out the parts, we see the basic components.
There are the front shock bodies and caps, which are threaded like the Kyosho Golds. The design, size and shape of these anodized aluminum parts are the same as the original Golds. I have not tested to see if these caps will fit on the Golds, but I suspect they might. The color, however is definitely NOT the same as the original Kyosho Golds. These Xtra Speed dampers are distinctly a pink-tinted gold color, not the deep gold of the originals. I think you can see the pink color in these shots. When sitting side-by-side with the original Golds, the difference is striking, but when alone the color is mild enough that you can get used to the pinkish color. I do not know why they are not the same color as the original Golds, but it could be in order to make it easier to distinquish the original Golds from these so people do not attempt to pass these off as original Kyosho Golds. If that was the reason for the color difference, I can totally understand and support it, even though I wish these were less pink.
The springs are painted black (possibly powder coated) and are smooth and shiny. The shock shafts are 3mm diameter and have two grooves cut at one end to hold the e-clips that hold the piston. The other end is threaded. The bladders are very soft rubber and are spherically domed. I think the original Golds had flattened tops on their bladders. The o-rings and e-clips are standard fare. The circular spring clips (cir-clips) are the same as the original Golds. They hold the o-rings and spacers at the bottom of the shock body exactly like the original Golds. The plastic parts tree holds the top adjustable clamp-type spring holders (2), bottom spring holders (2), top shock mounts (2), bottom ball ends (2), internal shaft guides/spacers (2), external shaft guides (2), and pistons (6) with three choices: 2, 3 or 4 holes so you can choose how much damping you want.
Assembling the shocks is basically the same as the original Kyosho Golds as you would expect since these are designed the same way. However, there are some differences that need to be pointed out.
First, when removing parts from the plastic parts tree, you will need to spend some time trimming off the flashing/burrs from the pistons and internal spacers to ensure there is no binding problem with the assembled shock due to the parts not fitting properly. Be careful not to remove too much plastic as this could affect the damping power of the piston if too much plastic is removed. This is where Kyosho's original Gold pistons were a bit better due to the way that Kyosho molded the pistons on to the parts tree.
Second, the pistons are not thick enough to take up all of the space between the e-clips on the shock shaft once assembled. The piston can slide up and down approximately 0.3mm when both e-clips are installed. This is unlike the original Kyosho Golds, where the piston was exactly the correct thickness and the top e-clip fit snugly when it was snapped on. To compensate for this I added a 3x5x0.3mm shim on the shock shaft before installing the piston. The shim removes all piston movement so it works as a single piece with no play and better damping once the shock is fully assembled.
Once the pistons were installed on the shafts, I moved on to installing the internal shock seal components into the shock body. This assembly process is exactly the same as the original Kyosho Golds. First, the first o-ring is installed, then the wide shaft guide/spacer, then the second o-ring and finally the thin shaft guide. The cir-clip is snapped into the groove that is machined on the bottom of the shock body.
While installing the bladders into the top caps, I came across some leftover metal shards from original manufacturing and machining of the threads. It's always a good idea to clean the metal shock bodies and caps to ensure there is no leftover material from the manufacturing process.
After applying some silicone shock oil to the shaft threads, I pushed the shock shaft though the shock body and out the bottom seal. Then I used non-scratching pliers to hold the shock shaft in place while I screwed on the bottom ball end.
I filled the shocks with oil, removing bubbles as per the normal methods and finished assembly. Here is another difference that only true Kyosho fanatics will notice: The top clamp-type spring holder installs the screw on the opposite side of the holder compared to the original Kyosho Golds. This is perhaps another difference purposely done by Xtra Speed in order to distinguish their design from the original.
My personal opinions:
These are exceptionally smooth shocks and feel exactly the same as the original Kyosho Golds. Absolutely no binding, and no bubbles (if you fill and bleed them properly). The bladder does its job.
In my limited experience, these do not leak, same as the original Kyosho Golds. But I don't punish my cars nor do I race them so take this opinion with a grain of salt. Since the design is the same as the original Golds, whatever you thought of the Golds as problematic, these will have the same issues.
I do not know if the spring rate of these is the same as the original Kyosho Golds (I have no way to measure). Of course you can swap springs if you want.
If you loved the original Kyosho Golds (W-5001 and W-5002) and wished you could get your hands on some reproduction shocks that were 90% the same as the original, these are exactly what you are looking for. Just beware that these are more pinkish in color compared to the originals. This is by far the most striking difference that could make or break your decision on whether these are right for you or your vehicles. As a side question, if anyone knows of a way to alter anodizing color and can think of a way to add more gold or take away some pink, let me know. As far as I can tell this isn't possible to do.
Basic specifications for the Xtra Speed Front dampers:
Hole center-to-center lengths (+/- 1mm): 52mm compressed. 68mm uncompressed.
Shaft diameter: 3mm. Piston diameter: 10mm. Outer case diameter: 12mm. Bottom ball end size: takes 5.8mm ball, like OT-33 or similar (ball not included in package).