Help with speed

[studysession]

I have a Factory team TC3. Hop ups coming out the butt.

I ordered a Venom Speed meter and I am going to do some speed and endurance tests with 2 different brushless systems. I have been reading articles on different RC cars.

Bigger pinion and smaller spur to go fast on the top end and less on the low end -- and -- smaller pinion and bugger spur to go slow on the top end and faster on the low end and give you more torque.

Why do I see so many fast cars using big spurs? These cars have serious top end.

:egad:

 

[Nitroaddict]

u have to remember 2 things.

1. changing the spur gear one tooth will adjust the ratio by about .12 but changing the pinion one tooth will adjust the spur by 1.0 - huge difference
2. Changing the spur gear by 10-15 teeth will still not make it visually much larger/smaller. so even though someone may have changed the spur by a large amount, it doesn't look like it.

got it?

 

[militarymaxx]

Aside from playing around with gearing changes. (And there so many possibilities). Keep in mind your motors optimum range.
If you ran a 72/15 setup and went 50 MPH (I'm using random numbers to make my point), logic would suggest that if I decreased my spur to 70 or increased my poinion to 17 or both and went with a 70/17, that it would go faster. Not necessarily
true. If the 72/15 gearing is optimal for that particular motors best operating range, then anything outside of that would be
counter-productive. Heck, if all I had to do was change gears to make it go real fast I would run spur gears and pinions that are the same size. (The closer you get to a 1 to 1 ratio, the faster you will go-but would need a motor that could handle such gearing). A cheap thing to do is go out and by different size spur gears and different size pinions. Experiment, make chart, record the data. You'll find that there are "magic' numbers that work better than others. Dont' forget to factor in motor type and that includes it's windings, battery type (NiCD or NiMH), and battery size as well as how many cells you are running.

 

[studysession]

Thanks - I ordered some different pinions and spurs and I am going to test and record and compare.

I am trying to figure out what's better for what I am trying to do. I been surfing google - reading different posts on gearing. Trying to figure it out.

 

[Wardo]

The larger the spur gear, the more torque can be made against it. It's leverage(sp?). Many use the largest spur possible and still be able to get the ratio they want.


You'd notice this in direct drive pan cars alot. They are down on torque to start and it makes the biggest difference on that type of car.

 

[studysession]

When my new spur and pinion gears arrive - I will be doing some testing of my own and comparing advatages of one setup over the other.:radio: