How to choose the correct gears for your RC

[mcvickj]

With the recent thread about the clutch and the great article about how to tune your clutch this brought another question to my mind. How do you choose which gears are right for your RC? How does changing the clutchbell affect the spur gear and vice versa. I did some poking around on the net and at RC Car Action's website but I haven't really found a great article that talks about RC gearing. Maybe somone has one that they can share with the rest of us.

 

[militarymaxx]

Here's a few rules to follow. If you want to go faster, that is more speed on the top end, make your spur gear smaller or make your clutchbell gear bigger. The closer the two gears are in size the more top end speed you will get. If you want to be quicker, more low end off the line speed, make the spur gear bigger or make the clutchbell gear smaller. The farther apart they are in size, the quicker you will be off the line. Keep in mind that if you gear too low you might risk over revving the engine. Likewise if you gear it to tall or gear it too fast, you might risk over torquing the engine.
As far as choosing which gears are right for your machine, you might want to look at the kind of track or area you run on and the type of running you do. Is the track built with long straightaways that are suited for speed ? Is the track full of short runs with lots of corners that would require quick acceleration off the line ? Or does it have both features ? Many guys will tell you it's trial and error. Start with the factory gearing and maybe drop the clutchbell by a few teeth. See what that does. Then go the other way and increase it by one or two teeth. Keep a chart, I do. I have included a link to an article. It talks about pinions. Don't worry, same thing as a clutchbell. In electrics they are called pinions and the same rules apply for electrics as they do nitro
as far as gearing. Good luck.

http://www.rc411.com/otherstuf/gearsoup-01.html

 

[mcvickj]

:bow: Thanks for the article militaryamxx. That is exactly what I was looking for. That clears up a lot of my gearing questions.

I just replaced my old TRX .15 in my maxx with an OS .15 CV-RX and it made me wonder if I should consider adjusting the gear ratio. Right now I am running the stock gears. I believe its a 72 tooth spur and a 13? tooth clutchbell.

I am thinking more offroad with this thread but you onroad guys are more than welcome to throw in your 2 cents.

 

[militarymaxx]

Glad it helped. I have been a member of both the traxxas forums as well as this one, and not to bash the traxxas site, I have received better service here. Many knowledgeable folks in here that can answer just about anything you need. And the cool thing is that if you don't necessarily use the right forum for your question, the guys are understanding enough to help anyways.

 

[NCNitro]

mcvickj, the stock gearing on a T is, spur-72, clutchbell-20. I went to an 18 tooth bell when I installed an OS in one of my Ts, I was thinking of trying a 17 next.

 

[mcvickj]

Were you happy when you dropped the bell down to 18?

 

[HumboldtBlazer]

I went with the Racer's Edge 19t clutch bell and a 72 tooth RRP slipper gear. With my Sirio .18 and pipe that setup seems to be great for short distance acceleration, but still have a decent top speed. I suggest moving 1 tooth at a time on one or the other gear, but thats me and I experiment a lot because I am learning and want to see subtule differences rather than large ones.

 

[SkyMaxx]

I run a 17T clutch bell on my Fantom powered T-Maxx, and it does great off the line, has plenty of low end grunt to get up just about any incline, and though it reduces the top speed my T-Maxx has been able to hold its own against Savage 21s.

 

[HumboldtBlazer]

17T holy moly low end my friend. I bet you can do wheelies all the way across your lawn..........sorry I couldnt resist.

 

[NCNitro]

I am very happy with the 18, I wanted mine set up for low end grunt, which is why i was thinking of trying a 17 next. You can get the Racers Edge bells for about $11 and that includes bearings too, not very good ones but once you find the bell you are happy with then you can get some sealed bearings for it. I have the Racers Edge 18 with dynamite sealed bearings and I like it a lot.

 

[HumboldtBlazer]

I too was surprised that the RE clutch bells was so cheap and it came with bearings. I am currently using those cheaper bearings on my Sirio and they work fine for now, but I only have about 2.5 quarts through it. I have the Dynamite sealed bearings as backups if they blow out. At first I was skecptical of the vented clutchbell as I thought a lot of dirt would get in and effect the clutch engagement, but no problems yet that I can tell and it did weight like 10-14 grams less than stock so it is less rotating mass.

 

[NCNitro]

I have an RE 18 on one of my other Ts with the bearings that came with it too, and so far, after about 1/2 to 3/4 of a gallon no problems with them at all either. You can't beat em for the price.

Thats a good half ounce of weight reduction, I did not know they weighed that much less, that's just one more plus.

 

[militarymaxx]

I run a 72 spur with 9 tooth pinions on my E-Maxx (sorry, I know this is nitro), but wanted to share the gearing I had. I use this setup for pulling. Top speed is like grandma in a walker. Tons of torque though. Fried the stock titans last pull. Oh the price we pay !!