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6 gear final drive ratio, pinion, motors

Posted: Mon Jan 16, 2023 12:52 pm
by graemevw
I've decided to get my old A stamp gold pan running again. I rebuilt it a few years ago and ran it on astro once but I remember struggling a little with gearing.
I think I had a 9t pinion (32dp gears), whatever the stock spur was, and a 16x2. I did have a 19x2 bit it was slow and overheated.
I'm hoping to be a bit more successful at getting the gearing right this time, and I think I'll use a tamer motor. I remember it being a pain trying to gear low turn motors properly.

Thought I'd ask you folks and see if I can find out the final drive ratio on these cars, what motors are recommended, and pinion sizes.

Last time I was just trying to make it as quick as my super astute which has a 14x2, or my 10.5t egress, or my 16x2 procat.
This time I don't want to be crashing the rc10, and don't want to blow it up. So am thinking going milder (19t-23t ish?) In the hope the car will still be fun, won't suffer as much damage, and will be easier to gear correctly.
Will also mean I'm not tempted to try and chase down every last bit of handling I can from the car.

So, what set up for a brisk, but safe/enjoyable car on small tight tracks?

Oh, and I deffinately want to stay brushed in this!

Thanks.

Re: 6 gear final drive ratio, pinion, motors

Posted: Mon Jan 16, 2023 2:08 pm
by ChocoTaco73

Re: 6 gear final drive ratio, pinion, motors

Posted: Mon Jan 16, 2023 7:24 pm
by juicedcoupe
I'd suggest switching to 48 pitch gears. It will seriously open up your gearing options.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 2:36 am
by graemevw
That's the rere and 48dp gears. The final drive ratios there though are no good for modified brushed motors.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 2:37 am
by graemevw
juicedcoupe wrote: Mon Jan 16, 2023 7:24 pm I'd suggest switching to 48 pitch gears. It will seriously open up your gearing options.
I've considered it. I'd rather keep it 32, but if I can't, I'll change it.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 7:02 am
by juicedcoupe
Here are some final ratio recommendations from back in the day. Keep in mind that those were based on racing conditions with older SCRC batteries.
Screenshot_20230117_055840_Gallery.jpg

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 9:08 am
by graemevw
Thanks, I can probably work this out from here.
Anyone know the internal reduction ratio of the 6 gear trans?

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 9:24 am
by juicedcoupe
1.83:1

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 9:30 am
by juicedcoupe
Also keep tire height in mind.

If you are running modern 2.2 tires, the effective gear ratio will be different.

Even though this is made for real cars, the calculations still work. Just put the different tire diameters and gear ratio in, and calculate the new effective ratio.

http://www.wallaceracing.com/gearcalc1.php

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 10:40 am
by graemevw
Great, thanks.
I'll write out a chart. Been looking into 48dp conversion too, I'll have to measure and see what kind of size spur I could fit.
If I want to keep it brushed, and if I want to push it with low turn motors and 2.2 tyres, I'd be looking at maybe a 96t spur or similar.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 10:51 am
by graemevw
Actually, probably wouldn't need to go that big on the spur. Fdr's are lower in 2wd cars aren't they, I'm still thinking 4wd.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 11:10 am
by BattleTrak
This would be good info to add to https://www.setupsplus.com/

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 12:05 pm
by juicedcoupe
Unless you don't plan on using a gear cover, I'd recommend a smaller spur.

With 48 dp, an 81-82 is all that will clear an RPM cover. 87-88 will clear the stock cover. That is with the 6 gear. The Stealth has a slightly different gear placement that allows for a little larger gear.

I have also modified a T2 cover and used a 91 on a 6 gear, but it was extremely close.

Re: 6 gear final drive ratio, pinion, motors

Posted: Tue Jan 17, 2023 11:48 pm
by Lowgear
BattleTrak wrote: Tue Jan 17, 2023 11:10 am This would be good info to add to https://www.setupsplus.com/
I was going to post the link, but the accompanying text about its lack of use thus far was going to be kind of bitter so I refrained. :| :lol: