I'm thinking about installing the MMM, and I've read most of the posts regarding brushless power in the summit. A lot of posts in there about blown gear and broken shafts. Does that happen in the process of learning how to tune it or harness the power so to speak, or is that just gonna happen no matter what. And if that is the case, how and why? It can operate in the e revo, so what is the trouble in the summit? Or is it just the case of people pushing it too hard. I mean, technically I can install it, and can't I turn it down using the link, so its not so maxed out fast. Or are the adjustments mostly with the brakes and other things and not speed or power? I want the speed and power, just don't see why shaft and diffs should be blown regularly.
They shouldn't be. I will say however that shimming at least the whole rear diff is pretty much required, but after having done so, they seem to hold up just fine. Proper slipper clutch adjustment is crucial however. Because of the Summit's larger tires, it's a pretty fine line between it slipping (and burning up) and having stuff break. Find that line and breakage should be pretty rare (well, excepting crash damage lol).
I occasionally do use mine on 6s too, and lately all I seem to do is wear the metal parts out on the shafts (only twice have I ever broken the plastic part, both times while doing stupid stuff with the diff lockers locked). Once in awhile I've had a bearing blow itself out (releasing all the little balls). Swapping the tranny idler gear bearings (main idler gear) and the rear diff pinion bearings should help here.
The MMM is fine and will not hurt anything if setup correctly. Run 4s with proper slipper adjustment and keep the lockers unlocked unless you are crawling. Even 5s will be fine if you are careful. It's when you try 6s that things start to blow apart and wear fast.
X3. The slipper needs to be set right. Too tight and the MMM eats parts. Lol
SUMMIT- DeWalt, 4S
Thanks for the info. I have steel center shafts if that matters. So the slipper would need to be loosened from the factory settings that I still have it at? And how much adjustments can be made via the link on the MMM? Throttle power?
Somehow I forgot a detail in my last post, and now they don't let me edit it here
I meant to say swap the tranny idler and rear pinion gear bearings to ceramic bearings. They can sustain the power better than stock steel-ball bearings.
As for the slipper, I adjust mine right just barely to the point I can do wheelies from a standstill. Any tighter than that doesn't yield any additional performance, but does increase the chance of breaking stuff.
As for adjusting the MMM's throttle, there's no real way to limit it's top speed other than to use fewer cells. The throttle curve adjustments alter only the progression of the throttle as you apply it, not it's ultimate top end.
I just want to avoid breaking a whole bunch of parts during the "learning process." Everyone says do this, do that, and most is just opinions based off they're experiences, which is fine, I'm just trying to be aware of the biggest things to worry about. Like shimming the diff? Thats tough for me to get how that would be necessary.
Why not use your end point adjustments in your radio to limit power if that is what you need. Of course you need a quality radio for this, not stocker.
Shimming the diff puts the gears tighter together, reducing or (ideally) eliminating the slop between the gear teeth. This gives the gears a better "bite" into each other which makes them less prone to breaking or stripping teeth (also, when the plastic differential case flexes under power, the amount of flex then has to be greater before the gear teeth are allowed to slip).Originally Posted by JJMILLER816
You want to shim the pinion gear closer toward the ring gear by putting a shim over the shaft right behind the pinion gear head (so it's between the head and the bearing). Then you want to go into the diff cup itself and put a couple shims behind the metal U-shaped thrust plates behind the spider gears (increasing their mesh with the side output gears).
Shims can be bought for the pinion gear, but the U-shaped ones you will likely have to cut out of some plastic packaging material yourself (such as the stuff small electronic gadgets come in).
See this post for some ideas: