RC10Talk - The Net's Largest Vintage R/C Community

My Kyosho knowledge aside from the monster trucks is severely lacking. Having built the re-re Scorpion and Optima, I'm very impressed. Far different from my plastic Tamiyas. Anyway, can someone elaborate on the performance differences between the original rear motor Optima series and the later Optima Mid series. I know Tamiya started with mid motor with the Hot Shot series but Kyosho tried rear motor first before adopting mid motor. How great a performance difference was the leap from rear to mid? Thanks.

The real big difference is drive train efficiency. A clean optima mid has a very free and efficient transmission. A rear motor optima is more draggy, and requires more maintenance. Unfortunately, both models tend to ingest sand quite easily, so they become chewed up quickly.

My first rc car was a salute (an optima with several options) and then I got an optima mid custom special so I can pretty well compare both.

The optima series was first launched with a chain drive, which was not very effecient and I also read it always ends up lengthening. My salute I bought with a belt conversion kit from the start so I cannot tell first hand for the chain itself.

The mid however had a belt drive straight from the start.

Still comparing both series with a belt drive, I noticed a big improvement when I switched to the mid: same engine, much faster acceleration with a quite similar top speed.

Another big improvement of the mid is the weight distribution: while the rear engine optima has a lot of weight on the rear axle, the mid is much better balanced. Consequence: corner speed is definitely higher with the mid.

Nowadays, no competition 4wd buggy has a rear engine. Tekno even went so far to put more weight at the front with the eb410.

Yeah tamiya and kyosho play in different leagues. Is it a wonder if tamiya is not very successful in high level competition?

The original Optima wasn't such a poor-handling car as some would suggest; it was a game-changer for its time. On some track conditions, it did very well due to its lightweight frame-rail chassis and excellent suspension.

In its original state however, it was prone to understeer on acceleration. Without a wing, it was prone to land jumps nose-first. And of course, the original chain required maintenance as it stretched, but that problem was all but eliminated with the belt-drive conversion.

The Optima Mid got everything dialed in and performed very well.