Hornet88

Thanks for posting those equations! Very useful info indeed. I think I’d take a trust, but verify, when it comes to brushless motor stats. I don’t have an analyzer unit, but they seem like a good investment, given the amount of money one might spend on a brushless motor. I was talking with one of the tech support people at Castle Creations who said that they typically don’t post their power outputs, because most other companies are dishonest about their own stats. That said, the 1410 series 3800kv motor has a continuous output of 400-450 watts. Having driven the motor a bit, I tend to believe him. Maybe one day I’ll pick up one of those analyzers...

I installed the castle SW4 with senseless 1410 series 3800kv motor. Very affordable, ridiculously fast, so far very positive customer support too! I was reading up on the strange numbers that kyosho lists for their 15.5t & 19.5t motors. A lot of folks out there seem to think it could also just be a typo. It is very cool looking though...

Thanks for the info! I picked up a few of those polypro hybrid pinions and I’m going to try a few out and see what works. Take it easy!

Solved it, I think... diff/final pinion (53/32) * counter/counter pinion (48/21) * spur/pinion (61/25). So that comes out to 9.237. Call it 9.24. I didn’t realize that I needed to divide the counter pinion into the counter gear and then multiply that in to the equation. Cant wait for some warm weather to take this sweet ride out and watch my four year old son smash the front end up 😏

Hello All, First time posting, so apologies if I err in some way. My question is about calculating the final drive ratio on a 2016 Kyosho Optima. They list the stock FDR as 9.24:1. The spur gear is 61t; pinion is 25t. They also sell an optional spur gear for brushless setups that is 51t, and they then recommend using either 30, 31, 32t pinion gear, which puts the final drive ratio at 6.24:1 (if using the 31t pinion). Now that just seems like a massive drop in the gear ratio, and wonder if anybody has ever done anything similar on this or other similar vehicles. Another thing that had me scratching my head is- how is their FDR calculated? I spent a badword of a lot of time on line reading different methods of calculating. I have tried running the numbers with the internal belt-drive pulley, diff gear, final pinion (internal), counter gear, and of course the outboard spur and pinion. No matter what I do, I can not replicate their claimed ratio specs. If anybody could kindly offer some advice, I’d be grateful. Many thanks, Ryan