Brushless Associated Monster GT

[squeeforever]

the reason they havent already is probly because it would cost ALOT of money to do it and that would drive the prices of the trucks up alot thus not much sales.

[Batfish]

Originally posted by squeeforever
the reason they havent already is probly because it would cost ALOT of money to do it and that would drive the prices of the trucks up alot thus not much sales.

I've considered this as well, but I think most people don't take into account what it already costs for today's electric MT.
Take the E-Maxx, for instance.
The normal RTR E-Maxx sells retail for $315.
Let's make some assumptions on cost for a brushless E-Maxx, based on retail cost of parts and other considerations. I'll get pricing from Tower, since they are the standard for competitive prices.
First, let's take off the parts we don't need/can't use with a brushless Maxx. I'll base this on putting in the Novak HV.
Remove:
Sliders, front and rear - $15
EVX Speed Control - retail $107
Titan 550 motors (2) - $40
Plastic idler gear - $3
So that's $315 minus $165 = $150

Now to add the parts to make it brushless:
CVDs, front and rear - $62 (we can be pretty sure that Traxxas will not put MIP or another high-priced CVD on the RTR, so I picked the lowest priced CVD set for the Maxx on Tower)
Novak HV - $275
Steel idler - $5 (this is based on the retail for the T-Maxx steel idle gear/parts...if Traxxas sells the steel idler for the T at $5, it's sure to cost them the same to make a steel idler for the E)
So now we have a brushless RTR E-Maxx for $150 plus $342 = $492.
$492 minus $315 = $177.
Now consider how many people have done these upgrades and purchased the Novak HV - don't you think many of them would have bought the brushless RTR for only $177 more than the cost of the normal RTR? Heck, I know *I* would have :)
To build it yourself would cost well over $600 and you'd have no chance of selling the brushed electronics for the same price Tower gets. I know that one prohibitive factor is spending almost $500 all-at-once compared to about $300, then upgrading when you can afford it, and that's the reason for my next point.

All this in mind, I personally think that the best first option for a Traxxas brushless truck would be for Novak and Traxxas to team up again. Traxxas should offer the E-Maxx in kit form for $200, a "brushless upgrade pack" with the needed CVDs and gears for $75, and include a rebate form for $50 off the Novak HV in the E-Maxx kit. This would still cost more than the RTR, but it would allow both companies to sell only the parts that people need and sell them in "package" form.

Anyways, I've hijacked my own thread :W:

[Batfish]

I finally got my lipo pack back from FMA and got to working on the MGT again in anticipation of getting it running.
I put the forwars-only conversion in and have now come to a new question. I've looked around and can't find an answer on this one so I figured I'd ask here first.

Does anyone know how to turn a one-way bearing into a no-way bearing?

If I can find a way to freeze the one-way in the tranny, I can get rid of the manual brakes and keep using the same transmission. One idea so far is to see if I can fill in the bearing area with solder, but I'm thinking that may not hold. The next idea involves (probably) a drill press. If I could get a hole drilled right through the tranny shaft and slot the one-way I could use a pin to hold the gear from spinning. If it didn't cost about $40 to replace the parts if I screw it up, I'd probably try it anyway.

Any other ideas? here's a pic of the one-way, if it helps anyone.

[coolhandcountry]

I don't think the solder is going to work. Unless you solder the bearing on to the shaft. I not sure if the solder will hold. I would jb weld it before that. Not sure though if you may need to take the bearing off for something. If not can you weld it some how.

[starscream]

Since The one-way bearing is required for 2-speed functionality, the only way this will work is if you are converting your tranny to a single speed. How big is the gear you are working with? You can most likely get a large pinion gear from Mike, or Stock Drive Products with a hub and set screw that would facilitate this. You would need to grind some material off the shaft for the set screw to hold properly. Or, if you're feeling really ambitious, you could bore all the way through the hub and shaft to allow a pin for support on both sides of the gear/hub.

Personally, I would stick with the 2-speed and move to a smaller brake servo.

[rchippie]

If your serious you can try mixxing up some jb weld. Then force it into all the open spaces in the bearing. I'v heard some of the crawler guys do this to there clod axels to lock the diffs. It's suppose to work very well.

[RC-Monster Mike]

I say leave it alone, Joe. Stick with what you have, or put in an e-maxx tranny.

[Batfish]

Mike - where's the adventure in that? :)
After getting inside the tranny and seeing how beefy the mod1 pinion/spurs are for the two-speed, and the steel drive gears, I'm pretty sure this one will hold up forever. Now I'm just considering dropping the manual brake.
Since I installed the FOC it's so much lighter that I'm very pleased with it.

Starscream - drilling through the shaft and using a pin was one of the ideas in my post. It's probably what I'll end up trying first. The one-way functionality isn't really required for the two-speed to work, only it's physical presence since the second gear spur bearing fits over top of the one-way.

If that fails, I can just jb weld everything together :)

[Batfish]

After reading a few other threads here and brainstorming some more I've come up with an idea that may work without physically modifying anything (thus not breaking anything :) ).

The second speed gear has one of those centrifugal force hub thingies to engage it. The hub is held onto the drive shaft via a set screw on a flat spot. The shift point is adjusted by a set/grub screw that you adjust by sliding a hex drive into a slot on the second speed gear to the set screw to loosen or tighten. If you can picture all that, you can picture my idea.
I removed the shift-adjust screw and took a normal screw with the same thread pattern, put that screw through the slot on the second speed gear and screw it in until the screw is even with the height of the teeth on the gear. This pretty much permanently engages second gear, which is stuck to the shaft via the flat spot and set screw.
This should eliminate the one-way and lock the tranny into second gear, effectively making it a single-speed transmission.

If it doesn't work out, I remove the screw and re-add the original set/grub screw and put everything back together.

I'll be trying this out later today (I hope) and will post my success/failures :)

[coolhandcountry]

Will it work in reverse is my only concern. It should work other than that. Let us know.

[starscream]

I agree with mike, the e-maxx tranny would be your best bet for this functionality. Because of the difference in gear ratio between 1st and 2nd gear, the one-way is required. If you lock your 1st gear on the shaft, I don't think you or your tranny will be happy when it shifts into second ;)

[Dafni]

Originally posted by RC-Monster Mike
I say leave it alone, Joe. Stick with what you have, or put in an e-maxx tranny.

Or if you feel creative, get a center diff!

I like that Idea the best so far. :)

[Batfish]

Well despite all of the other advice I went ahead with my most recent idea of turning my MGT tranny into a single-speed locked transmission. :)
The way I did it I can switch back to normal if it doesn't work out. I did not change any stock part at all.

Here's what the screw looks like in the second gear to lock it:



And here's all the parts from the transmission I don't need after the FOC and my idea were implemented. The first gear spur isn't even used now, as it's locked into second.



Here's a link to a short video of the tranny in action outside of the vehicle.

http://www.rcpics.net/view_single.php?medid=63505

Once I put the electronics back in I'll see how it works and holds up.

[Batfish]

Originally posted by Dafni
Or if you feel creative, get a center diff!

I just noticed this post, Daf. I have a couple extra OFNA Ultra MBX center diffs around. You might just have something there...I'll see how that might shape up.

Back out to the garage! :)