GCM EXO build- The Stocker Shocker


Maybe take up knitting.
Well, it has begun. A thousand small parts and some heavy hours with Allen wrenches later, this thing will be done. Unfortunately I am forced by my too-technical personality and habits to go over everything 8 times and drink vats of coffee during this build, so might take a while, but I'm going to post it all right here.

The next thread will be the 'Mod' thread, this one is the stocker setup.

Any one else notice the tires stink like gassy rubber?! The whole shop stunk right after I opened the box! :rock:



Yes the package is very potent. Good luck with the build Chris!


Tires stunk like gassy rubber?
I love that smell!

Good luck with the build and post plenty of pics please!


Maybe take up knitting.
Awe, Shoot. It's already modified. Dang.


Yes, that's a GCM Center diff kit, and if you hate maintenance and want to actually drive the thing all the time, then this will be on your 'list'. Some of you don't know this, (but some do) GCM has been in the diff kit upgrade business for 7 years already, and no one has to come back :laugh:


and of course the front and rear had to be done also. I should also add, these will have a nice little setscrew on the side to fill them up after they leak out over time. I should never have to take this out ever again.



Maybe take up knitting.
Diffs: Not on the site yet, but will be after testing etc. (not like I need to test an already proven product, but...)

So next steps are coming: I'm never satisfied with just the usual 'stick it together' because my experience more than not will prove to me that this means problems later down the road. The diff pinions is a perfect example.
Back when we did tons of E-Savage builds, the main building problem with those was the diff pinion play. Guess what I found out with this Exo? Same thing. To make the pinion sit nice and smooth and get out all the shaft sliding (read: makes heat in the bearings for nothing) I added this 5mm inside diam. shim to the cup side. This also protects the exposed bearing from other odd elements that could get in the way. Never know, so more protection is better in this case. I'm going for the 'no maintenance' build, after all.



My next mod comes at this time. These sorts of builds, which are half aluminum and half plastic, have the chance for uniform hardware. It doesn't work as well to put machine screws into used holes, but it sure works well to use machine screws first time in a new hole! I switched all the plastic coarse thread screws with these regular M3 machine screws in every case. I'm so crazy, I also measured each hole and used the maximum screw length that would fit in each hole, just to have the maximum thread in every case possible. That's a bit crazy I know, but there were some in the build that Axial could have used longer screws for sure. (and I did).



Maybe take up knitting.
Next up is the steering for me. I don't do much in order, so I'm on to that now.
The basic instructions are great on the steering assembly. Interesting to me that the whole steering assembly is held to the truck on plastic mounting areas, but we shall see if that poses any problems. May be fine, just was unexpected to me.
I did find one complication. The basic upgraded servos I like to use are a tiny bit deeper sitting than most stocker servos, and in this case, that poses a problem. First off, even if I had the cheapest smallest servo, it would appear that the steering would hit the servo at full left cycle, and in my case, since I have to space the servo away from the mount by 2mm (too deep and hits center brace) the steering DOES hit the servo. I had to clip off the one mounting tab from the front top of the servo to make the steering arm stay clear. There's not much room in this for a servo for sure. I had thought about making new mount holes in the chassis plate, but really, I just got lazy.
Servo tab clipped, and 2mm spaced off the mount. Lower pic shows how the servo is touching the center brace full contact. Wire looms are a nice touch!!




Maybe take up knitting.
Next up for me: Battery mounting.
Turns out I had a missing tapped hole in the chassis. Got hole. Got no tap! So ran the M3 tap through there, and done like dinner. I also discovered, due to my lazy already-sat-down-situation that coffee makes a real good tapping fluid! haha! So great to have another use for the stuff.


Got the battery trays fitted for my 5200 and 6000 hardcase 2s batteries.. another problem. For some reason, (if you have an answer please help, this is odd.....) The battery won't sit down in the holder all the way. In every battery I have, the thing is about 1/2 mm too wide to actually fit down in to the holder. Wha?? Anyway, you can see it here, the battery is sitting on the ledge basically ON the edge of the outer screw. I'm going to have to do something about that, because the battery can in fact slide around a bit more thanks to not being down in the floor. Hmmmmm.



New member
how many millimetres wide is your pack ?

I'll photo my setup with my maxamps hard case and measue it up in a bit for you !


Maybe take up knitting.
All my hardcase packs are 46.35 to 47.24 mm wide, and the opening in the battery tray floor is only 45.84 at the widest possible place. After that you sit on the screw heads.

Please PM me with what you got, Thanks


Maybe take up knitting.
And, some more info and pics:

Got the diffs done using the production parts, fully tweaked, and assembly video done and ready. These are Sick as heck. [[[


More beef than a Texas Ranch. I love solid diffs... in fact I just love metal stuff. haha


Loaded the center and the ends with these, got the 20k in the center and 10k in the ends for lube and flow. Should work well. Might be a bit tight for the ends, but we will see. Very smooth diffs. Very smooooooth.




Maybe take up knitting.
And yet some more...

So I noticed when assembling the diff ends to the framing, there's a nice little gap there at the aluminum joint, so I made a little RTV black gasket there and then assembled it. There's going to be no end of dirt in the diffs if this doesn't get done. Mine should last forever, considering I think that was the only place in the whole diff case that was open at all.... Bet it works!


Now, The steering bar is rubbing on the input cup at the front. Actually only rubbing on the setscrew for the cup, not the cup itself. Not really sure of a solution outside of grinding the top off the setscrew. May have to do that. It will click all day and make me mental.


I didn't notice anything in the manual about power recommendations. I checked the box, looked all over and see nothing. Why is that? Do they not have any sort of recommended setup for powering this thing?
Ah well. I figured it out for myself. There was a 40-72 4pole 2650kv motor here, a 20t pinion, and a MambaMaxPro, so that should do it. May have a bit of a wheelspin problem. :laugh: Wasn't sure that was going to fit, but it does, and not a half mm bigger would have. :bugeyes: I think it added a pound to the thing. haha. Did you know that the MambaMaxPro fits real nice into the Sidewinder ESC clip? Works great!



Putting it in "H"
From the website:

For maximum performance, we recommend a 540 or 550 sized brushless motor.
? Minimum 4 pole 540 recommended (3300KV or more)
? Maximum 550 4.5T recommended


Maybe take up knitting.
Ok, so my overgearing and too much torque should do it then! I'm sort of hoping for a backflip. Haha

Ugly Duck

You might like metal stuff, but you're sure being mean to it all. That's a lot of motor!

Me likes.


Maybe take up knitting.
3 cheers for Axial on making spots to hold down the wiring. Of course I modified things a bit, can't help it I think. Maybe there's a medication for that.....
I put the motor wires out the can towards the center, then loops under the rear support, and then joins into the speed control wires UNDER the esc.. under the esc plate also. Then I attached the ESC plate, and they are sandwiched in there and also won't come undone by themselves ever. Great. Then I trimmed off the larger of the wiring clips, and used them reversed pointing out instead of the stock 'in' direction. Works well for me, it's clean as anything, and I like it... Also bound the RX, did all the ESC checking and setup, and installed a 3rd channel extension wire to get the 3rd channel out of the RX box for later use.. or for re-binding or whatever. I hope I never have to take the RX box apart ever again. Nothing rubs anywhere, and it's nice and solid. The switch mounting is yet to be seen after the cage and shells get installed.
I think it's the cleanest wiring I've ever done! Nice! That's a lot of motor, eh!?!



Generis you asked for advice with the battery tray.
Call Axial is my first advice because they re-released EXO's as you know...http://axialracing.com/wordpress/2012/02/09/axial-exo-status/.

Try a peice of foam or styrene under the battery to raise level in the tray if it doesent pose a clearence problem with install of the cage or when changing batts.
My better half suggested 'popsicle sticks' :laugh: