fragile spur gears???

Hi guys... i run a, E-maxx with a feigao 9L, and 14 cells, 70/16, andd BigJoe tires...
Since I try to have more acceleration in programming my TX, i destroy all my spur gears... With 75% of EPA that works correctly, and when i arrive at 80% I begin to ear a bad sound... and some teeth of the spur gear are completely flattened... Is it due to the heat of the motor that melt the plastic spur gear? (my motor, axle and pinion are pretty hot, and my motor plate also... more than 100°C)
I run a RRP slipper, 70/16 ratio ... All was right until I tried to have more punch in modifying TX parameters...
Someone told me that it is due to my slipper, that is tightened too much... is it right???
I tried to add a fan on motor but it did nothing better... Do I have to run a steel spur gear with my alloy pinion??? I think that's it's not the way to solve my problem...
Please could someone help me??? Does someone know the best ratios to run my setup???

[sjcrss]

70/16 is pretty tall gearing, and no i don't think the motor being hot will melt it, but if you have the slipper set to loose, especially the RR one, it will generate heat and cause the spur gear to fail.....you need to crank it down as tight as possible, and make sure your gear mesh is as close as possible, I use a thin peice of paper to set my mesh, and it works great...try this gearing....16/66 ...everything will run cooler and you will get better speeds if the motor and surrounding areas will not be hot....I think your overgeared and it is causing heat issues or you have something binding in the tranny or in your drivetrain...check it all out and drop your gearing soome and see what happens...

[squeeforever]

Sjcrss, 16/66 is a taller gearing then 16/70...Try something like 13/66. Your motor and ESC are getting WAY to hot. You want to try and keep them around 160* F or below.

[sjcrss]

ooops my bad.....didn't realize that...thanks squee....then I'de try the 13/66.....if you need a 13t pinion I have one....

[squeeforever]

Usually, you would run something like 14/66 or maybe even 15, but the Big Joes will require a lower gearing.

[Gustav]

I think you need to gear up to more like the stock gearing if the motor is all that hot.What are the esc and battery temps like?
Edit:forgot about the big joes,the gearing squee suggested sounds about right in that case.

The heat is probably coming from the slipper slipping too much though,you need to tighten it down as much as possible,seems like your melting the spur gears.Probably the reason it doesn't do it at 70% epa is the slipper isn't slipping then.

Oh guys you're really helpfull, all thanks for that! i will try to modify my gearing like Squee said before, then tight the slipper a little bit less...
For ur information, my esc stays cold, no problem on that side... but my motor is at more than 100°C, because a little drip of sweat became steam when i put my face over the motor to see what was broken... not more than 120/130°C imo... what is impressive is the temperature of my motorplate and of my pinion!!! i never encountered this problem before (before i ran a HVmaxx, and this feigao9L with a 74/16 ratio....) 74/16 ratio was well and funny to run, until i tried to gear up with a 18T pinion... sorry i discover the limits of the Feigao 9L... :(

I will let you know what happens asap!

fab.

[coolhandcountry]

If you keep running your motor at 100C. It is not going to last. Just some helpful advice.

How many cells you running on the 9L to?

[sjcrss]

[QUOTE]E-maxx with a feigao 9L, and 14 cells but the question is what controller is he running?

[brijar]

I run an E-Maxx with a 9L and a 9920 and the motor gets about 140°F, usually a little less, on 16/66 doing mostly high speed street running with 14 GP3300's. The ESC is usually less than or equal to 120°F. I run stock tires though and have a fairly lightweight truck with barely any aluminum at all. I am running 16/72 because it's about 104°F outside right now:036::013::026:. I am fairly happy with the speed, but could someone let me know if I am seriously over or undergeared? This seems to be the motor/ESC's happy gearing, but I would like the motor to run a bit cooler. I haven't stripped any gears with my setup, though my tires are so old they can't get enough traction to lift the front tires up unless I floor-it on my cement driveway.
Just thought I'd let ya know as I run a similar setup.

Brijar!!!

[neweuser]

You could have Mike make a 14 pinion for you. Otherwise, put a heatsink on the motor...

[jhautz]

In my experience with the 9L 14 cells tends to make the motor very hot. You are spinning it almost 45,000 rpm at that rpm its gonna get hot. I have much better luck w/ the 9L when I keep it down to 12 cells or 4s lipo.

At 14 cells and the 9L you will constantly be fighting excess motor heat. 14 cells works, but its really pushing it.

I have no problem running a 9L, BK9920, 16/66 in an emaxx on 4s lipo or 12 cells. I can run it all day and never get the motor or esc over 120. But just to be sure I have a small fan on both the motor and esc.

If you continue to have heat issues, I'd cut down the cell count.

Edit: Or get a bigger motor...

[squeeforever]

Faggz main problem is the Big Joes in combination with the over gearing.

[crazyjr]

Originally Posted by squeeforever

Faggz main problem is the Big Joes in combination with the over gearing.

And the smaller motor, if you want the big joes, you need an XL

Okay guys, it seems to have been fixed... Squee was right with his ratio proposal :)
I also untighted my slipper and now I can play with 100%epa... but top speed is considerably affected.
Motor temp gets down, and had to cut 2 wing of the heatsink (my model is a 540C 9L+9920) to catch the right gear mesh with the 66t spur......
>>> Do you think that I can try 18/66 without problem?
>>> Can someone give me a range of ratios to run with my BigJoes, I only have 40series 6.5"tires...(mulsher, masher, bigjoe)?