I'm new to the board and a couple of members asked me to provide more information on my "neglected" Kyosho Optima. I say neglected because over the years, I've taken parts from this car to complete other projects.
The car was originally built to overcome the limitations of the Hot Trick conversion (which I was racing at the time). I wanted to eliminate the use of the aluminum plates because I wanted to run a stick pack from front to back. In order to do this, I decided to use a "pan" design...but the only way to mount the gearboxes to the chassis was to use an Ultima rear box and an Optima Mid front box.
Shortly after I finished building this car, ROAR eliminated the 4wd stock class. The car sat while I concentrated on my Jrx pro. To this day, the car still isn't 100% complete. I think it's time to finish this project.
File comment: optima 1
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File comment: optima 4
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File comment: optima 5
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The rear suspension seems to have generated some interest so here's some information. The original rear end used a passive rear steering setup similar to those used on a Porsche 928. As the rear is compressed, toe in is decreased. When the rear suspension is fully extended, toe in is increased. Around corners, it gives the car additional steering. This was a very good system on tracks that were relatively flat (no big jumps). The suspension was removed and replaced with the one pictured below. This version addressed 3 things:
1. Adjustable toe in - The tie rod at the rear was a stationary pivot. When the front tie rod is adjusted, it causes the hub to be turned slightly. This gives the ability to adjust the toe in by about +2 / -2 degrees. The rear hub is from an older Traxxas.
2. Adjustable wheelbase - The rear arms can be moved back by 1/2 an inch (spacers behind the arm). If you look closely at the rear shocks, you will notice spacers as well. The shocks were designed to slide back along with the rear arms.
3. Full suspension travel using the shorter front shocks - I wanted a lower profile for this car. The mounting point of the shock allows full suspension travel.
File comment: optima 3
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File comment: Optima 2
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I used a ton of different parts for this car:
Kyosho (optima, optima mid, ultima)
Losi (jrx pro)
Traxxas (bullet or ???)
Tamiya (modified JG blackfoot bumper)
Hopefully, I can rebuild this thing back to the original design...which included disc brakes for the front wheels.