9920/9L Question
 

Hey everyone i am just wondering what kind of gearing i should use on my e-maxx. I'm using a stock chassis with a gorillamaxx single speed, cvd's all around, bowties on 40's, and geared 72/16 with 12 gp's, and also a ubec. I went out for my first run and the 9920 was barely warm but the 9L was 180 degrees. Should i be gearing different. Btw mike the fan is great.

Try gearing up a touch, actually. 17/66 should be a pretty decent gearing to start with. 180 is a bit warm, but it won't hurt it.

I knew you could help mike, i just actually got back from outside and went down to a 14 tooth pinion and it got 190 after like five minutes. So i guess i am backwards at thinking, i'll try 17/66 tomorrow.

It just takes a bit to find the "sweet spot" based on your individual truck. I wouldn't say your thinking is backwards, just "brushed" thinking is all. With brushless, it will get pretty hot when undergeared or overgeared. LMK how the 17/66 works out.

Why does a brushless work like that. I would have thought the same thing about going down to a 14. What does it let the motor over wind or something.

It is a loaded question Coolhand..

Brushless has got a certain point where it delivers the power at the highest efficiency it needs. I can be that a truck runs cooler on 16 cells than on 12..

So am i hurting my truck/system by only using 12 cells?

The brushless seen is so confusing. Yet so exciting. So if your motor is supposed to run on 12 - 18 cell and you run it on 8. It may run hot cause your not in the efficency range. That is wierd yet cool.

No, that's not what i said, i was explaining how odd brushless can be..

Odd can be good yet bad. I go with this odd is a postively good thing.

very good..

The other odd thing about brushless is that you can power a washing machine with a small brushless motor.

Now that is the kind of stuff i talking about. I like that about brushless. It is vesatile.

Well mike i went and changed gearing to 16/66 and yeah it did make a difference, i know got temps of 167 degrees on the motor after a full run on the batteries and the 9920 stayed very cool.

What is a safe temp for a motor to get up to?

my washing machine has a bushless motor :p

I don't know for sure, but i think 180-190 is kind of on the high side but still considered safe. Mike would know for sure.

I really need to get a temp reading. It seems mine is running warm but not sure how warm. If i keep it below 170. I think i will have no problem what so ever. thanks mike d

Welcome, i hope i am right. Are you running a 9L as well, if so what kind of setup are you using and how many cells?

167 is a good temp after a full run. Glad te gearing changed worked for you. 190 is on the high side(safe, but too hot for my liking). Keep things below 180 for long term motor friendliness.

Mike_D, how did the 9L perform on that 16/66? I'm running 16/72 right now and it seems a bit warm. I've got a 66T spur but haven't put it on yet.

Any info is appreciated!

Thanks!

It runs very well on the 66 tooth now, oddly i get about the same power ( it wheelies on command ), faster top end and cooler motor temps. I would change from your 72 to a 66, it worked very well for me.