Spur gears
 

It seems more and more RCers are using 72t spur gears.I understand with pinion gears less teeth=more torque and more teeth=more top end,but what are the pros and cons of,say a 66t vs 72t spur gear? Why choose one over the other?

The gearing works the opposite with the spur gears. The more teeth on the spur, the lower the gearing (slower). Pros and cons are only a matter of finding the right combo for your track. Personally, I like the 66 tooth spur gear and locking the tranny in second gear. This way, I use a small spur and a small pinion and keep the weight as close to the center line as possible. Certain motors may require lower gearing, which would be a reason to use the bigger spur gear. Other than gearing selection, there really is no advantage/disadvantage to either size.

I no longer have time to race,but if I took my Emaxx with a 9L/9918 brushless combo,66/18 gearing and went to 72/18 gearing what if any difference would I see in my performance? Thanks

You would see a slight drop in top speed and a slight increase in torque and runtime. It would be like dropping 1/2 tooth on your pinion. Not a super noticeable difference at all.

Thanks you for your time.

My pleasure.

Hey guys...FIRST OFF I WANT TO SAY THIS SITE IS KICK A**...Now to the question...I was wondering if you had any good links on this subject. I am getting confussd with the ratios...the more teeth on the spur the lower the speed...arent you supposed to change the pinion..becuase its easier...

ok...as you can see I am a noob to the r/c world...but I am loving every min. of it so far....I have a E-Maxx and my only problem is I wish I had more batteries to run this for hours on end....

Now I have been looking into upgrading parts of the truck...and the gears is sometihng that I think I want to do...but I just have to get a better understanding....Basically, I want to get as much speed as I can .....I am definately going to a brushless motor..I am stilll researching that as well as the ESC..I was thinking the 9l with the warrior 9918..

Anyway...Im not gonna sit here and take up much time...so if you can give or direct me to some knowledge of this gear thing...that would be great....Please talk to me like I am the dumbest person in the world...I just want to make sure that I understand before I break anything....thanks again....

Keep up this site...IT ROCKS..:D

Prince26 Welcome to the forums.

If speed is what you are after you should get some good battery packs. A couple of 7cell GP3300s will get your stock emaxx to 30MPH. The GP3300 cells are top quality cells that will have a longer life the some of the cheaper cells out there. Plus you will get better perforance. The GP3300 are a little more money up front but you will save in the long run. This will get you both speed and allow you to add batterys to your collection.

The 9918 and 9L is a great combination. Depending on the number of cells you will be running will determine the motor you should get to go with the 9918. Here is the breakdown.

12 cells: 8L
14 cells: 9L
16 cells: 10L

I personally have the 9918 and the 9L because all my packs are 7 cell packs. A lot of racers run the 8L because they run 12 cells to reduce weight. The 8L on 12 cells is about the same as the 9L on 14 cells.

Hope this help.

Prince,

In addition to what Netman posted, the actual gearing your run will depend largely on several factors, such as how you drive your truck (bash vs race vs speed runs), what hop-ups you have, what tires you have etc.. I can guide you in the right direction based on your needs when you actually get a system. If you need further help selecting the system that is right for you, I can guide you there as well. Welcome to the forum!

Thanks guys for the great info....I was actually planning on running 12 cells...I am looking for race and speed runs....I am planning on getting another E-Maxx for bash...

I will definately keep you guys updated as to the progress of my EMaxx...I know I will need some guidance for the gears....Thanks you guys for the info...

If the performance of the 8L on 12 cells is about the same as the 9L on 14 cells, then why would anyone buy the 9L with 14 cells when they can save weight with the 8L?

The 9L will draw less amperage and get a longer runtime with similar power output vs the 12 cell 8L set-up. This would be the main reason for running this setup. Also, many people upgrade to 7 cell packs before eventually going brushless, so it makes sense at that point to go with the 9L setup.