r/arrmagroms

Sorry for the long post but I'm explaining what I did to this little monster.

Pretty happy with what I was able to figure out to upgrade my quake grom. I got this truck used and with the money I saved going that route I was able to upgrade it to the monster it now is for only a little bit more that what a new brushed version is and this has brushless so (in my opinion) it's better in all ways. 

As you may know, the battery tray is a big issue. It takes a certain spektrum battery and it's hard to get anything else to work with the layout. I 3d printed a battery tray adapter to work with some cheap ovonic batteries from Amazon. Works great so far.

I went with the hobbywing system in it cause I like hobbywing and the spektrum stuff was like $50 extra and I wanted to get away with not using it. It may have been worth the price in the end with time spend 3d modeling but now I can say my car is custom lol. 

I had to make a mount for the esc and receiver. This wasn't bad. Just a square piece double sided taped to the grom servo adapter kit. The hardest part for me was doing the motor mounts. Arrma only sells the motor mounts for 16mm apart bolt holes and the motor I had had 16 or 19mm holes but the way the motor is designed I had to use the 19mm holes so the wires would actually fit and come out the top. So I modeled a new motor mount. It's not super impressive but with my limited modeling skills I'm very happy with what I was able to figure out. 

Had to build body spacers cause the new esc is a little too tall so this gave extra room for airflow reasons and so it didn't rub on the body. 

I upgraded the shocks to the arrma aluminum shocks. I much prefer aluminum shocks to plastic composite shocks even though the internals on these are the same with both styles. 

Only thing I'm now needing to do is get a better servo for it and the build is done. When the body and tires get worn out I'm going to switch it over to the purple style cause I like that color combo better than the green.

Several months ago I took my kid to a hobby store to let him pick an rc vehicle. He went with a Gorgon Grom and off we went. It was a considerable upgrade from the couple of toy rc cars he had but we couldn't leave it alone. He is into monster trucks and wanted it to be more like a monster truck. We started by replacing the tires to give it even more of a monster truck look. This added a lot of stability, and somehow makes the truck end up right side up most of the time after a tumble. Next we added a trimmed Mojave front bumper and I made a new wheelie bar to match the taller tires. Steering in grass was weak, I replaced the steering servo and threw in a metal steering assembly while I had it apart. Truck was fun like this, but seemed like it could get away with more power. I picked up a mini kraton motor and ESC from eBay and can confirm it fits with some minor clearancing for the heatsink to fit. Currently running a 18t pinion sprocket, but will try a 20t soon as it seems to be coping with the speed just fine. Playing with the programming of the esc has really gone a long way with making it easily drivable. It was time for a new body after wearing out the original body from several trips to the skate park. The boy opted for a quake body and I think it was the right choice.

This kit and wheel set was a level up. So fun!!!

My Typhon Grom BLX suddenly started making loud high-pitch grinding noises on throttle and accelerated much worse than usual. I suspected that the gear mesh could be too lose after my last re-assembly, but then noticed very uneven wear patterns on pinion and spur.

Assuming that I'd need new gears anyway, I put everything back together to see if I could get a last session out of the gears, but the grinding was still there and eventually I entirely lost drive.

I'll get new gears, but I also want to figure out what the root cause could be to avoid this from happening again. The motor-pinion axle seems stable and the motor mount on that chassis doesn't allow for much wiggle room that could explain the motor and pinion being angled.
Months ago I had no drive and this kind of grinding since a tiny stone had found its way in, but removing it fixed the issue without visual impact on the gears.

Any ideas?