2 Speed or not 2 Speed, that is the question.

[MAC FAB]

Ok guys, yes or no on a 2 speed? If yes, which one and why? I am looking for something that has a very wide range between hi and low. +/- 30 mph hi and about 10 mph low. What fits in the Bomber and handles horsepower? I can make a Summit 2 speed work, but no drivers with it, Godzilla trans. Am I searching for a unicorn????

Or, (pause in thought here) do I keep it simple and run direct drive with a sensored/brushed motor and keep the top speed down? What are you guys doing and how does it work?

[calcagno45]

Are you overlooking the Axial 2 speed for any reason? AX31181

I still say no 2 speed, just go brushless. The Holmes PP3500 on 3s has plenty speed but can run 4s if more speed is needed and get to that 30mph number. 30mph in a Bomber is a bit squirrelly though.

[svt923]

The SSD 2 speed kit for the Bomber/Yeti has a really wide spread: low is a 2.34 ratio and high is 1.0.

A setup good for 30 mph in high gear would drop to about 13 mph in low gear.

[MAC FAB]

Originally Posted by calcagno45

Are you overlooking the Axial 2 speed for any reason? AX31181

I still say no 2 speed, just go brushless. The Holmes PP3500 on 3s has plenty speed but can run 4s if more speed is needed and get to that 30mph number. 30mph in a Bomber is a bit squirrelly though.

Not overlooking anything actually, I'm looking to get educated in the fast lane. I'm just wanting to be able to crawl and then go race the Trophy Trucks. I get go fast, it's making the go slow part my challenge. With that HH3500, you can crawl just fine and still go fast? 3s gets you going how fast with this setup?

[84yoda]

Yes, that's why sensored brushless is the way to go.

[shiftauto]

Not sure if I'd say trophy truck fast but plenty fast for a bomber. Plus it has nice slow speed control. The whole reason I don't mess with the 2 speed is because of the Sensored/brushless combo. Using the Monster X or Mamba X esc allows on the fly drag break too. Turn it off and bash, turn it on and crawl.

[slowmethinks]

I have a Tekin ROC412 3100 in my Wraith. Not sure of top speed, but it will go pretty darn fast. Faster than it needs to be. But it also does a FANTASTIC job of going slow as well. That's with 3Sl.

So I second the sensored brushless vote. (or third or fourth or whatever)

I run a 21.5T HW sensored brushless in my son's Bomber. It's probably not nearly as fast as you're wanting to go, but I think the 17.5 or 13.5 would put you there. According to HobbyWing, the 21.5 is 1800Kv, 17.5 is 2200Kv, and 13.5 is 2800 Kv. The Justock kit is $97.49 for motor and ESC. The downside is they aren't water proof at all if that matters... But I epoxied the outside of my ESC case and used dielectric grease on the motor sensor connector.

https://www.hobbywingdirect.com/coll...nt=27465886664

[maslin]

You'll be frustrated and broken fast trying to keep up with anything built for speed. 20mph is about all that's controllable, a brushed 2wd slash will walk it in a field.

[DukeMinnix]

another vote for censored brushless. I run the mmp/roc412 combo. I crawl on 2s, bash on 3s. at full throttle its almost uncontrollable on 3s

[Lavaheadache]

as previously stated, just go sensored brushless unless you "must" have a 2 speed. I have a Mamba X sensored bomber with 2 speed and love it but it is mostly novelty. In actuality the sensored brushless setup makes the 2 speed moot.

[calcagno45]

Yep, my Bomber is still geared stock 11/64 which nets about 21mph. Gear up a couple teeth or volt up to 4s and it can easily be in the 30mph mark. And yes with the MMX, aux drag brake on the fly, its smooth as glass crawling while still being able to rip.

[MAC FAB]

Originally Posted by maslin

You'll be frustrated and broken fast trying to keep up with anything built for speed. 20mph is about all that's controllable, a brushed 2wd slash will walk it in a field.

Actually my build stems from speed. Fully independent, the same footprint and rear suspension as the class 1 buggies I build, they go 30 all day long. That said, I've got a 2400kv Mamba Max setup I can run then and see how it does. 2 speed desire was to go real fast and real slow; so that looks to be a pipe dream then, right? Going direct drive simplifies life I guess....
A 550 can 3800 ish kv sensored got too much top end for the application?

[DukeMinnix]

I'm sure custom independent front and rear suspension changes handling dynamics.

My previous comment still stands though, you can go real fast and rear slow both, and have it be very controllable down low with a censored brushless setup.

[MAC FAB]

Yes on the handling dynamics, and everything is metal so nothing to break. It will go fast, I just hope it will crawl.

So riddle me this guys: Why not run a 2 speed, go slow AND fast with the SAME battery? Is it that the extra moving parts/electronics are an issue or just something else to go wrong and or break/fail? My buddy says do it electronicly, run 2-2s batteries on a direct drive setup. Solenoid switch between them for voltage. Just have to "restart" your car at each "shift" so you have a few seconds of off time at the shift to re-boot. Go fast with 4s or go slow with ~160% capacity of the individual 2s C rating.

[maslin]

You can always run 3s and not pull the throttle all the way back.

A quality setup geared well, with a good battery, will go slow or fast just fine.

[allanon1965]

if you want to race with trophy trucks, get a trophy truck. a bomber is locked front and rear diffs with solid axles. at 30mph will be damn hard to control and in my opinion, impossible to run with a trophy truck group race. There will be alot of rolling over, done by the bomber, unless you modify it with IFS and open diff in the front..

[turbodan13]

For what it's worth, re: 2 speed for slow, I'm running the SSD kit in my Yeti. Gearing is stock, but slipper is upgraded to a Robinson unit, MMP & Tekin Pro4 4000kv, on 3S. As far as how fast it goes, I have no idea of the exact speed but it's easily fast enough to run away from 2wd & 4wd SCTs, etc. When it's kicked down in low range, it will easily crawl through most anything, but still top out at a quick jog. I ran the 2spd at Axialfest this year, and really only used the high range when I had it out in wide open areas. Personally, if you're considering it as a means of having a "do all" rig, I feel that it's a worthwhile upgrade. Yes, it adds a little more weight/complexity & an extra servo to the mix, but the truck was engineered for it, so it's more or less a direct fit. After running the 2spd Yeti, I'm building up my Bomber as a 2 spd truck. The Yeti handled 90% of the AF trails with relative ease (and maybe a bit of technical driving), but I did also see the short coming of the open diff (and already lacking turning radius) and large flat belly with turtle-like ground clearance. Bombers were handling things with far greater ease. The 2spd will definitely increase the versatility of the Bomber.

[durok]

MAC FAB's build is custom-made. IFS front and rear - thread here:

MAC FAB Bomber build.

I think with the extra weight and IFS, a 550-can sensored brushless 3500kv or so should be great. I personally would not run a 2-speed.

[CoolRunning]

The 2 speed regardless of the sensored setup will offer you far greater resolution. No question about it.

My brushed motor in high gear cannot crawl anywhere near as carefully or controllably or as slowly in high ratio as it can in low ratio and that is a brushed motor! Imagine a brushless setup which has a high kv with a minimum level of motor turn...that is clearly not going to be as good as a low kv brushed motor going slow.

2 speeds are awesome. It will keep things cooler too boot.

[MAC FAB]

Originally Posted by CoolRunning

The 2 speed regardless of the sensored setup will offer you far greater resolution. No question about it.

My brushed motor in high gear cannot crawl anywhere near as carefully or controllably or as slowly in high ratio as it can in low ratio and that is a brushed motor! Imagine a brushless setup which has a high kv with a minimum level of motor turn...that is clearly not going to be as good as a low kv brushed motor going slow.

2 speeds are awesome. It will keep things cooler too boot.

You've spoken what I've thought all along. With the 2 speed, I shouldn't need a Keith Black hemi for all the hp, or maybe I do but can put the power more where I need it, making it easier to drive, like a 1:1 with compound low. No big deal about servos, I already have 3 in it. Steering and front/rear diff locks. Is there something 2 speed out there that is somewhat inexpensive that works, be it Bomber, Wraith, Yeti? Maybe the Rock Rey has something that will work. Looking for a zero maintainance piece.