Trinity/AYK Optima – part 1

Please Take Notice

This is not a webshop, and beside what’s listed under the “FOR SALE” tab in the menu, nothing presented here is for sale, so please don’t ask. If I have anything I would like to sell, I’ll post it in the “FOR SALE” section.

The AYK/Race Prep suspension arm set for the Kyosho Optima, before I set them free.....

Some of you might have seen my other ongoing Trinity Optima project, the “Trinity/Hot Trick Graphite Optima Ram“. That car was based on the Trinity graphite chassis (#8013) and top plate (#8014) upgrade parts for the Hot Trick Optima Ram conversion kit. But in addition to the Optima Ram upgrade chassis, Trinity also made two other graphite kits for the Kyosho Optima, one consisting of four standard style front and rear side plates (#8022), as well as the kit used on this build, consisting of left (#8018) and right (#8017) full length side plates in the style of the later AYK 4WD buggies, like the Pro Radiant.

AYK/Race Prep Pro Radiant with the full side plates, not unlike the chassis plates on my Trinity/AYK Optima build. Photo source: unknown (if it’s yours, let me know)

Trinity also made a special graphite top plate (#8019) for these kits, as well as graphite front (#8021) and rear (#8020) shock towers. I have used a set of original #8017/8018 side plates, but the top plate and shock towers I have redrawn from the originals, and had Jeff Malar of Factory Works cut repros for me. The Trinity front tower was made to be used with the longer rear shocks, instead of the standard Turbo Optima front shocks.

The Trinity repro top plate and shock towers that I drew and had Jeff Malar of Factory Works cut for me.

The shocks I have used on this build are not the Kyosho gold shocks, but rather the Duratrax copies. The Duratrax golds are very similar to the Kyosho golds, but are more prone to leaking as they miss the double o-ring seals of the Kyoshos, hence their nick name “duraleaks”. This project will be for the shelf, so there will not be any oil in the shocks. Some of the Duratrax shocks can be distinguished from the Kyoshos as they have a brighter gold colour, as opposed to the more faded gold of the Kyoshos. This is however not a 100% safe way of telling them apart, as I have found a few Duratrax shocks that have the same faded gold colour as the Kyoshos. A better way of telling if it’s a Kyosho or a Duratrax is to have a look at my guide here.

Which is Duratrax and which is Kyosho golds?

This being a “Trinity/AYK Optima”, I found it proper to include a couple more Trinity parts, in addition to the graphite chassis parts. The upper control arms, both front and rear, as well as the steering rods are the adjustable gold rods that were sold by both Trinity and the Japanese brand Tech Racing. I’m not sure, but I believe these were made in Japan by Tech Racing, and imported to the US by Trinity. I say this as I have seen many more versions of these small gold coloured parts from Tech Racing than I have seen in Trinity packing.

Some of the Tech Racing parts for Optima, Mid and Ultima. Several of these pars were also sold by Trinity in the US.

Even if the car has full side plates, some kind of rails have to be used to hold everything together. The Optima wreck that I used as a base for this build came with a set of cut rails, where only the front and rear parts were left. I decided to use these on the build, instead of full rails, to save some weight. With the graphite side plates and the top plate, the chassis feels more than sturdy and stiff enough, even without the full length rails. The cut rails were from a Optima celebration gold chassis kit, as was the OT-14 front under guard, and a few of the other aluminum parts. To build further on the black/gold theme, I decided to keep the gold celebration parts, and added a gold Option House W-0101 motor guard as well. To seal the under side of the chassis from dirt and small stones, a kydex YSP full under guard has been mounted.

This was how it looked when I got it. It did have a Trinity graphite rear shock tower, but I used that for another build. The front tower was a butchered aluminum Optima Mid tower that I just threw in the bin, and the fiber glass top plate was from JG Mfg.

I also found a set of Cross (I think) gold anodized aluminum rear hubs and front hub carriers, but the front steering hubs are the black Andy’s. All ball screws are from Tobee Craft, and are gold anodized as well. The wheel axles are also gold anodized, and are from the earlier mentioned Tech Racing series. I’m not sure if these axles were sold by Trinity, like the adjustable tie rods were. I have a few sets of the gold Tech Racing/Trinity kingpin bolts, shown in the picture above, but I actually decided to use the standard black kingpins, as I like the contrast between the black and the gold. It’s not the purpose of this build to have as much “bling” as possible, but rather to have the gold nicely balanced against the black graphite. As I have used the gold Tech Racing wheel axles, I couldn’t mount universal drive shafts, so I decided on using the standard black Optima dog bones. We’ll see if I keep it that way or if I drop the Tech Racing axles in place of Option House or Phoenix universal swing shafts. The gold axles are barely visible when the wheels are mounted anyway, and I really like using universals on “racer builds”.

The hubs and hub carriers I believe were made by Cross.

Well, the title says “Trinity/AYK Optima”, but until now the only thing with this build that could be linked to AYK or Race Prep is the similarities of the Trinity chassis plates and the latest AYK designs. AYK/Race Prep made a lot of hop up parts for a wide range of cars, including a strong and lightweight gold anodized aluminum suspension arm set for the Kyosho Optima, much in the style of the red suspension arm sets made by Hot Trick for their various red buggy conversion kits. Race Prep was the US distributor and co-developer of AYK’s racing buggies in the last years the AYK brand existed. According to former World Championship participant and AYK/Race Prep team driver Steven Dunn, this AYK/Race Prep Optima suspension arm set was made by AYK in Japan, and not by Race Prep in the US.

Some of the parts put together, I’m still undecided about a few things, so this will most likely change quite a bit before it’s finished…..

The drive line consists of a complete Kyosho Option House W-0105 belt drive conversion kit, and is fully ball raced, including the small belt tension spool in the rear gear box. The differentials on the build are the gear diffs that came with the conversion kit. It’s also possible to use the Option House ball differentials for the Optima Mid series, as they are direct replacements and fits right in to the Optima gear boxes.

The belt drive kit comes with e a new gear box with an integrated spool/belt tensioner. You’ll find the full instructions in the document depository.

To further add to the gold theme, I’m temporarily using a Kyosho Le Mans 480 Gold motor for power, and a gold anodized KO Propo RM-7 480 electronic speed controller from 1983, but I have an AYK Magnum 480R motor coming in, that will be used to add some more AYK to the mix. The RM-7 480 ESC was the first KO ESC to carry the “KO Propo” name, as the earlier ones just said “KO co., LTD”. It’s also quite small and light compared to the earlier RM-7’s. Because it’s a pre-FET controller, it is rated at a moderate 25 A continuous, and has a max. peak rating of 45 A. The Magnum 480R motor is quite “mild” with its 26 turn armature and 20.000 RPM, so they should match perfectly.

The LeMans 480 Gold that’s currently in the car, but to be swapped for the AYK Magnum 480R. To the right the KO Propo RM-7 480 ESC.

If you find some of the parts on this build to be rare, you are right. Especially the graphite parts and the Cross wheel hubs are pretty rare, and you don’t see those very often. But that’s actually nothing compared to the AYK suspension arms. I have only seen one other set of these for sale in all my years, and that set was well used. I have seen a couple of similar NIB sets for the last generation of 4WD AYK buggies, but I feel very lucky finding one NIB for the Kyosho Optima, even if the auction went quite crazy and pushed the price a bit over the top. I just had to have those, as I couldn’t know if I would ever find another set. Since these are so rare, I nearly shed a tear when opening the pack. But as we probably are the last generation remembering this old stuff, I think both the monetary and sentimental values of these vintage parts are at a peak, as no one will ever enjoy them as much as we do. So I think it’s stupid to keep the parts NIB and not use them for what they were intended for.

Japanese AYK ad from 1987 showing the gold suspension kits for the AYK buggies (left) and the Optima (right).

I have not yet decided on a body for this project, but I’m leaning towards a Turbo Optima body, or maybe I could get the body of the AYK Boost to fit? I think the Boost body looks very nice, and I think it would be cool as it’s a AYK body. The body needs to be cut at the front, like the bodies used on Hot Trick Optimas, as the Trinity front tower has a closed top like the Hot Trick front tower. The AYK buggies have the front tower much further forward than the Optima, so there will be some trial and error to find something that will both fit and look good. No matter which body I finally settle for, I have an idea of a paint job in the style of the AYK Boost box art, only with gold instead of orange. At this stage, nothing is carved in stone.

I might go for the AYK Boost body and look..

As for the wheels, I had originally decided on using the re-re gold plated Turbo Optima wheels that were offered through that infamous Kyosho crowd funding project, but as that project was scrapped, the future of the gold version is in doubt. I have told Kyosho (as if that should make any difference… lol) that they should release them as an option for the forthcoming Turbo Optima re-release, as I believe they could sell well if offered through the normal channels, and not that Japan-only crowd funding campaign. If they’re not released I actually have a few other options. One option is to use a set of Kyosho Optima Mid Custom/Custom Special wheels dyed black, with either a set of Schumacher CAT tires or some Kyosho Option House tires.

I may try to dye a set of these black, if I go for the AYK Boost body option. I have an idea that they could look a bit like the Boost wheels, if they are black…..

But most likely I will use this set of Condor wheels that came with tires looking a lot like the spike/V pattern of some of the AYK tires (see the image above, with the AYK suspension arms). I haven’t received these yet, so I can’t confirm anything regarding the tires, but it was advertised as coming with AYK tires….. I’ll just have to wait and see.

Condor wheels for the Optima, advertised as “coming with AYK tires”.


Please Take Notice

This is not a webshop, and beside what’s listed under the “FOR SALE” tab in the menu, nothing presented here is for sale, so please don’t ask. If I have anything I would like to sell, I’ll post it in the “FOR SALE” section.

About TomEG 69 Articles
I have been into RC cars since the beginning of the 80's, but have really never been much of a racer. I competed in some local races and some "Tamiya Cups", and actually came 6th in the Tamiya Cup Norwegian Nationals in 1987. My main interest has always been building and modifying, and that's where I still am today. Through the years I have been able to build a solid network of contacts around the world, consisting of both former and current members of the industry, as well as quite a few of the former top drivers. I have a genuine interest for the history of the 1/10 scale off-road buggies from the 80's.


  1. I am impressed by your knowledge, i did not know that AYK did parts for optima. Amazing build as usual but this time it’s special
    With the parts used. To combine two of my favorite brands Kyosho and Ayk? Brilliant! Tobee cross Andy’s and trinity..well i will take notes for future projects, many of these fine brands i had forgot about. Good thing to be reminded, keep up the fantasic work Tom, i really enjoy reading about old school rc

  2. Hi Tom I was wandering how I could get some kyosho custom special wheels like the 2 yellow sets in your photos thank you

    • Hi Ted.
      They’re called OT-67 and came with the Turbo Optima, Salute, Optima Pro and the Gold Optima. Only places to find those are (as with most vintage parts) ebay and facebook groups. Be prepared to pay premium money, though, as those are amongst the rarest Optima wheels to find new, and I’ve seen people asking up to $250+ for a NIB set of four.


      Here is the file for those wheels in my parts database:

    • Well, it says ¥5000 on the price tag, so that’s probably what they sell for, if they are new and still in the pack 😉 Just kidding, of course. The problem is that there are far too few recorded sales of this kit to really answer your question. New in pack would, of course, be worth quite a bit more than a used set. Whether the set is complete with the fittings that came with it would also affect what someone would pay, and of course the state of the parts, if they are used. If you could send me a picture of them to (remove the XXX, YYY & ZZZ from the e-mail addy), it would be easier to put some kind of “price tag” on them.

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