I just found a 9 tooth brass pinion gear that fits! [UPDATED]

[matts175]

Pinions (the small gears) Radical RC

I just ordered 2 of them. 9T 0.3 mod 1.5mm shaft.

1 tooth doesn't sound like a big deal, but check out the math...

10 tooth pinion, 54 spur is 5.40:1
10 tooth pinion, 56 (HR) spur is 5.60:1
9 tooth pinion, 54 spur is 6.00:1
9 tooth pinion, 56 spur (HR) is 6.22:1

 

[scx10 honcho]

so i ant real good on the gearing does that mean it will go slower or faster?

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scx10 honcho
micro scale buggy

 

[DSchulten88]

so i ant real good on the gearing does that mean it will go slower or faster?

________________

scx10 honcho
micro scale buggy

Smaller pinion = slower

 

[scx10 honcho]

ok thanks


___________
scx10 honcho
micro scale buggy

 

[CHOPPERMECH11]

what spur do you plan on running? Also what speed control/ motor setup are you running?

 

[matts175]

what spur do you plan on running? Also what speed control/ motor setup are you running?

I ordered the HR 56T. ESC and motor are both stock. I am using a 7.4v LiPo and I want it to slow down and have a little more run time.

 

[Elastokinematic]

is that going to increase your run time? essentially what you are doing is traveling a shorter distance per motor rotation. So does that lower gearing decrease amp draw and therefore increase run time? Im thinking you are going to get less gas mileage.

 

[matts175]

It should increase run time because it will be less amp draw and as a side benefit... the motor should run a little cooler. Mostly doing this though because of the torque increase and it'll be able to crawl slower.

Also, can't really consider "MPG" when talking about a crawler. Time should be the concern. If you took 2 bone stock crawlers and geared one 17/50 and another 9/56 and put them on a big circle track, of course the 17/50 one is going to get more total laps in, but I'd bet that the 9/56 one would just keep chugging along long after the 17/50 one dies. Now take those same 2 and make them climb a 60* angle the whole time. The 17/50 one is going to die out wayyyyy before the 9/56 one because it's going to draw a ton more amperage.

 

[matts175]

UPDATE:

I does fit, but it's very tight on the shaft. What I had to do was remove the motor and hook power it. While it was running, I held the shaft on a metal file for about 10 seconds and all was good. It still fits tight, but it is manageable. Pitch seems perfect and it meshes like it should. So 0.3 mod is the correct one.

Here's a picture and a video. Please note that it is very loud because it is on a thin plastic table. it's not that loud when it was in my hand or in the air.

9 tooth pinion test. Micro Rock Crawler. - YouTube

 

[Markhpnc]

Is it still working out ok for you? I'm thinking of ordering a few of these :mrgreen:

UPDATE:

I does fit, but it's very tight on the shaft. What I had to do was remove the motor and hook power it. While it was running, I held the shaft on a metal file for about 10 seconds and all was good. It still fits tight, but it is manageable. Pitch seems perfect and it meshes like it should. So 0.3 mod is the correct one.

Here's a picture and a video. Please note that it is very loud because it is on a thin plastic table. it's not that loud when it was in my hand or in the air.

9 tooth pinion test. Micro Rock Crawler. - YouTube

 

[matts175]

Yes. It's still working great. I even used a 9 tooth on my brushless 4500K install.

http://www.rccrawler.com/forum/losi-micro-rock-crawler/342842-help-me-find-brushed-esc-please.html

 

[8695Beaters]

Thought I'd add an update. I picked up a few of these pinions and they DO fit on the shaft if you lightly tap the motor on with a rubber mallet. BE WARNED!!! Use somethin to hit the commutator and not the case or you can split the back of the case like I did. It is a tight fit, but it does press on if you're gentle. Using an actual press would be smart as well.

 

[Baddad]

Just ordered 2! Thanks for the info:ror: I'll update with results later

 

[anuthabubba]

What worked for me was to place the pinion on a wood block, then the motor on top of that with the shaft down. Then a punch held on the other end of the rotor shaft. Gently tap the punch (with a small brass hammer) to drive the shaft into the pinion. The wood block helps prevent damage to the brass pinion and there is no force on the can.

No need to file the shaft. It fits but there is metal to metal here, not metal to plastic.

 

[Fungi]

I used a vice and no other modification to the motors shaft. I only had to put in a spacer to press the shaft not the case. Now to get the HR gear...