Coming soon .....GMADE GOM-GR1 Rock Buggy

[Barndog Racing]

Yes Eddy's are sealed and tighter I think that is why I was trying to get the axles first because they would be in the worst of the dirt and stuff.I also did the bearing on the spur gear and it spins nice!

[Dustinf]

There, I've ordered enough bearings to do both axles completely and have some spares.

I did have a bearing for the spur gear, I ordered that ahead of time. It definitely helps although I don't think my slipper has slipped at all. I might have it too tight or in not pushing it enough.

I'll feel better once I've gotten them in there. I can't stand slop like that... which is something that drives me nuts on my Yeti, tons of steering slop.

At least this isn't that.

[Teng]

Originally Posted by mikemcE

On my R1 the biggest issue was bearings, fast Eddie solved that issue quickly . Get a full set and you will eliminate all sorts of issues.
Be wary of junfac CVDs , I blew 4 out quickly, when I went back to stock no issues. I did go 4WS to make it turn.


Hang up and Drive

Hi Mike, do you have any idea Fast Eddie bearings under what scale? ABEC 3 or 5???

Thank you

[mikemcE]

Couldn’t say, Eddie puts sets together. I think abec3, but not sure


Hang up and Drive

[TooOldForThis]

I'm still far from finished but last night I got mine put together enough to go for a quick rip around inside the house. Some observations:

I have the same loose front wheels that others are talking about. I'm interested to hear if new bearings make a difference.

I had trouble getting the wheels to stop wobbling like they weren't on straight (not to be confused with the looseness mentioned above). I'm still not sure what was causing it, but I think it had something to do with how the wheel hexes were seating on the axle shafts. After some fiddling and removing/installing the wheels and hexes a few times, the wobble is mostly gone. Strange.

The gears are nice and quiet, which is surprising considering how many there are.

I have a 20 turn closed endbell (brushed) motor in it right now, and it was slow. The gear ratios seem good for crawling but are too low for what I want to do. I'm going to try a 17t pinion and a faster motor.

This is my first experience with a Hobbywing 1080 ESC, and I'm impressed. Very smooth and easily adjusted with the programming card it comes with. I like the backlit pushbutton on/off switch too.

[Jay-Em]

I used the Axial 21t from my Wraith. With the included 13t pinion it was, indeed, slow. Crawler slow, watching paint dry, slow. Changing it for a 16t pinion made some difference. It’s now about as ‘fast’ as a Tamiya DT 02 on a stock 27t Mabuchi rs540sh with a 17t pinion.

It won’t break any records, but it’s a beginning. I got a 15t laying about. I believe it’s non-timed ( remember: The GOM has the motor turning clockwise, contrary to about any buggy on the market. Running a brushed, fixed timing ( ! ) endbell motor will lead to overheating and eventually burning the collector badly)

If the 15t won’t work, I got a well-maintained Orion v-brush 19t double with adjustable endbell. I wouldn’t be surprised if a 19t double is in the ballpark for a bit of crawlability in 1st gear, and still some speed on 2s in second gear.

[TooOldForThis]

Originally Posted by Jay-Em

( remember: The GOM has the motor turning clockwise, contrary to about any buggy on the market. Running a brushed, fixed timing ( ! ) endbell motor will lead to overheating and eventually burning the collector badly)

Can you elaborate on this a bit? Are you suggesting that this truck will eventually burn out any fixed-timing brushed motor? Adding to my confusion is the closed-endbell (presumably fixed-timing) motor shown on the GOM's box art and elsewhere.

This will be good info to have while I'm motor-shopping.

[Brake Weight]

Can you flip the diffs?

[84yoda]

As long as the timing is set to zero, it should be fine.

[HumboldtEF]

I was finally able to edit the short video I shot of my brothers Gom crawling

https://youtu.be/1haXrFT8lmo
this thing crawls pretty well, I think the only upgrade is the proline tires

I'm also having trouble embeding video


EDIT: Okay i found out whats going on with embedding, only certain sections of the forum allow embedding, I was able to create a thread in the Video section and embed the video there

[Dustinf]

I've ordered some Duratrax Scaler Cr 2.2's. I was able to get 6 of them with rims for only a bit more than two extra stock tires

They seem nice, but I've never run them. For the money though.. they should do alright and look nice.

And I'll have 2 spares to mount however I like.

[Jay-Em]

Originally Posted by TooOldForThis

Can you elaborate on this a bit? Are you suggesting that this truck will eventually burn out any fixed-timing brushed motor? Adding to my confusion is the closed-endbell (presumably fixed-timing) motor shown on the GOM's box art and elsewhere.

This will be good info to have while I'm motor-shopping.

Sure.

Usually, closed endbell notors -other than the standard Mabuchi rs540sh- that are advertised as tuned/timed, are meant to run counterclockwise when looking at it from the front/pinion side.

Rotating the endbell ( and thusly the brushes) a few degrees counter to the rotation direction of the motor, is a sure fire way to get more rpm out of it. I bet You’ve heard of “27-degree stock motors”. That means that the brushes are set at 27-degrees counter the center of the magnets. However, when the motor is running clockwise, while the endbell/brushes are àlso rotated/adjusted clockwise, it will start to arc and heat-up, and lose power in no uncertain amount.

Only a closed endbell with the brushes centered above the magnets, and consequently running the same amount of rpm forward- and backward is considered 0-degree timed. Axial’s motors seem to be. (Tamiya is one of the few manufacturer that actually prints the rotating direction on the cans) . So people relatively new to the hobby often get confused when purchasing a ‘tuned motor’ and running it the wrong way around and then it burns, without gaining any speed for the car.

Historically, Since the early Igarashi 05’s, motors in hobby-grade rc cars run Counter-clockwise. Usually referred to as ‘CCW’ There were some exceptions, early Marui’s, and some Kyosho’s, but CCW has been the industry standard, so to speak. Hence most closed endbell- and ‘stock’ tuned motors are tuned for running CCW.

If You want to run brushed -which is still a sound choice for a crawler with bashing potential- You better invest in a brushed motor that can be timed by Yourself. You can have a good brushed, ball bearing supported open-endbell motor for as little as $20.- Open endbell motors usually come with timing marks/notches on the can, and two little screws in the top. Loosen the screws, and rotate the enbell any way You want, as long as it is counter to the rotation direction of the armature/shaft.

A few degrees of timing is a good way to get a lot more rpm out of a brushed motor, without losing too much torque. Most hardcore crawler motors are used without timing, afaik. A lack of rpm is usually fixed by just upping the voltage of the battery. Even a humble 27-turn will get quite peppy with 3s. Peppy enough to -with the “right” gearing- start breaking axles on cheapish china-cars....

Brushless motors are also offered with “timing” but they work quite differently from brushed motors, especially on the ESC-side, so “timing” is a bit of a mis-nomer. The end result is the same, though : more rpm at the cost of a tiny bit of torque.

Sorry, quite a bit of text, but motors- and tuning has been part&parcel of my/our hobby since I bought my first Marui Big Bear somewhere in the late 80’s ( I feel ooooold... ) and there are sooo many misconceptions and -frankly misleading -mostly from manufacturers- claims about electric motors for rc, that they became a study-subject, and even a hobby, of its own....

By the by, flipping the diffs -like on the AR-60 axles in f.i. The Wraith- is regrettably not possible on the GOM. It wóuld have been the easiest solution to the “fixed timing conundrum “ plùs it would have allowed me to use my beloved LRP stockspec and their waterproof esc’s. *sniff*

[Teng]

Good morning USA, Just in case you guys missed this video, GOM Options parts video: https://www.youtube.com/watch?v=G6PI...ature=youtu.be

[TooOldForThis]

Originally Posted by Jay-Em

Sure.

Good stuff, thank you.

So if a motor is advertised as fixed timing with no other information, is it safe to assume it is set at zero degrees? The example I am thinking of is the Reedy Radon, which is a 17t open endbell with no specific timing info I can find, aside from it being "non-adjustable fixed timing". (Great cheap motor btw, I run one in another vehicle)

I don't mean to get too far off into the weeds on this topic, but I think it's still a relevant discussion as the GOM has this uncommon motor rotation.

[mikemcE]

To solve reverse rotation, sensored brushless , use a castle or holmes esc and reverse the motor with castle link


Hang up and Drive

[Brake Weight]

Can the axles be swapped front to rear and rear to front? Then the lockouts and Chubs swapped.

[Jay-Em]

Originally Posted by TooOldForThis

Good stuff, thank you.

So if a motor is advertised as fixed timing with no other information, is it safe to assume it is set at zero degrees? The example I am thinking of is the Reedy Radon, which is a 17t open endbell with no specific timing info I can find, aside from it being "non-adjustable fixed timing". (Great cheap motor btw, I run one in another vehicle)

I don't mean to get too far off into the weeds on this topic, but I think it's still a relevant discussion as the GOM has this uncommon motor rotation.

Sorry, nope. When a tuned , low wind motor is advertized with “fixed timing” it means that it’s ‘fixed’ at -usually- 15 degrees or more for CCW running

Best way to test is just listen to the rpm when directly connected to a battery. A very slight difference in tone pitch between running forward, or backward means it’s 0 degrees, and only runs a bit better the one way because it is run-in that way. A lárge difference in pitch means it’s timed several degrees.

The highest pitch is the designed rotation direction.

The radon 17t pushes 30000rpm from 17turns, which indicates some timing going on. 17turns usually deliver around 26000 to 28000 rpm unloaded, un-timed.

My advise : don’t buy a non-rebuildable brushed motor. Rebuildable motors guarantee that the timing can be adjusted for any rotation direction (have You considered the Yeah Racing Hackmoto V2 17turns? Rebuildable, ball-bearings, all for about $17.- )

[Jay-Em]

Originally Posted by mikemcE

To solve reverse rotation, sensored brushless , use a castle or holmes esc and reverse the motor with castle link


Hang up and Drive

Would work for none-stockspec motors. Not for the LRP. Base timing, factory fixed, is already 15degrees for ccw running.
The K4, luckily, isn’t timed. Only problem is fitting an ESC under the bonnet. It’s a tad low up there. I think I’ll cut part of the -to me- useless RX box. That extra 1,5cm will guarantee a brushless sensored esc with fan will fit.

[Dustinf]

Originally Posted by Jay-Em

Would work for none-stockspec motors. Not for the LRP. Base timing, factory fixed, is already 15degrees for ccw running.
The K4, luckily, isn’t timed. Only problem is fitting an ESC under the bonnet. It’s a tad low up there. I think I’ll cut part of the -to me- useless RX box. That extra 1,5cm will guarantee a brushless sensored esc with fan will fit.

Thanks for the lesson man, I've learned a lot.

You know your stuff!

[Jay-Em]

Originally Posted by Dustinf

Thanks for the lesson man, I've learned a lot.

You know your stuff!

You’re welcome!

Funny detail: I never thought that my archaic knowledge of brushed motors would be of any use anymore since I, and the rest of the world, went fully brushless somewhere in the late 90’s, early noughts..... until I discovered crawlers and trail-trucks.

Back to the GOM.

I was struggling to find an out-of-sight place to fit a receiver and a light-controller box. But lo’ and behold. After putting-in the interior, I discovered that behind the chairs there is a perfect little tray to stick electronics to. More or less protected from the elements by a bit of roof and the radiator.

Only thing needed now are some servo-extension leads, that are already on order, together with a nice Hobbywing 1080 to replace the Hpi 15wp. ( I plan to stick with brushed for now. It’s full-on fall overhere. A very WET fall. )
I have a little more faith in brushed motors in the wet. Too much trouble to get sensored brushless fully watertight, ( and I’m out of plasti-dip) though, truth be told, the fact that the motor sits up high dóes help with that.