Grom Ok here’s my quick Grom build

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fredw90

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Bought two groms about a week ago, decided to pick up a third a one a few days later.

I started off by designing an esc mount for the servo. This is slightly larger than the one available to purchase from arrma. Does it’s job well only took me a few hours including print time and a few revisions.

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After that was the power plant, I love castle stuff but wasn’t patient enough to send the micro x2 back to CC to have it swapped out for one with a built in BEC. This chassis is too small for that much wiring. This is a 390 sized sensored brushless motor. 4500kv.
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Now I did want to run this sensored so I had to make a small notch in the chassis. I wish the battery tabs would have been lined up towards the top but because of the hole spacing on the can this is the only way they would fit.
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Up next is ESC. I had a spare Hobbywing just stock laying around. It s a 1/10th scale 60a ESC. So I did some measuring and it’s roughly the same foot print to the Micro X2 so I decided to go with it.
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Up next, shocks. Too impatient to wait for arrma shocks, saw that someone posted a link for these on amazon. 20$!! Plus everything is interchangeable, and by everything I mean, springs, spring retainers etc. They’re almost identical. Stock springs are a little long so I stuck with what was on them because I wanted the truck to sit a little lower.
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Up last is just finding exactly how I wanted to route everything, found a way I was happy with. Here it is compared to stock form. Overall it weighs about 50grams more than stock. Not too bad. I do have an NDSRC micro servo on the way but that hasn’t shown up yet. These stock servos aren’t bad it’s just a ton of slop in the steering assembly.I bet there will be a mini typhon released at some point, that’s what I’ll save the servo for.

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Here’s the final setup I decided to go with after getting the sensor wire routed.
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Those Justock escs were nice I have one in my EMB-1.

I noticed you aren't running the cap pack does that have an effect on the esc?
 
Those Justock escs were nice I have one in my EMB-1.

I noticed you aren't running the cap pack does that have an effect on the esc?
It was a free second hand esc. If it pops it pops. I’d be more concerned if I was running full size stuff on it. But I can’t see it being too much of an issue with this tiny stuff. Only time will tell.

It does standing backflips if it’s got the grip. I need to pull the diffs and make sure the screws holding the cups are tight just to prolong the possibly inevitable.
 
Can’t wait to test those shocks as they’re plush AF compared to the garbage arrma provides. I’d suggest some heavier fluid in the rear however! I went with 40wt but might actually go more once the brushless combo arrives so it doesn’t squat too quickly under power. 👍🏼

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Can’t wait to test those shocks as they’re plush AF compared to the garbage arrma provides. I’d suggest some heavier fluid in the rear however! I went with 40wt but might actually go more once the brushless combo arrives so it doesn’t squat too quickly under power. 👍🏼

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I went with 1000cst 😂😂😂
Great job Fred, turned out MINT!! 👌
Thank you sir!


I also have the new motor plates on the way, I’d like to gear up to a 20t pinion. On surpass website it says only 2s on the motor, I did a few passes on 3s and was only warm to the touch. Also need to break out the GNSS.
 
It was a free second hand esc. If it pops it pops. I’d be more concerned if I was running full size stuff on it. But I can’t see it being too much of an issue with this tiny stuff. Only time will tell.

It does standing backflips if it’s got the grip. I need to pull the diffs and make sure the screws holding the cups are tight just to prolong the possibly inevitable.

The vehicle I have mine in only weighs 2.2lbs so I have often wondered if the cap pack is needed.
 
Power to weight ratio laughs at 80 grams, clean build!
 
If you can find some adjustable turnbuckles you could tow it just a tad for more stability at high speeds. 😉
Yea arrma makes some. I’m wondering if I can piece some together. Stock servo isn’t bad but the whole steering assembly is loose. I need to find some aftermarket springs that are a little shorter.
 
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Heres the gang.The GF wanted a pink rc car, so I bought her a Grom and painted up a pink body.

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Picked up some more parts. Tires are 80mm with a hydrid off-road/Onroad tread (with foams!).

Some more gears, 23t and 26t. Just to do some more experimenting to try and find the sweet spot for 2s. Going from 16 to 20 made a world of difference.

And… picked up a properly fitting 3s lipo, not this old gensacearespammers that has the leads coming out of the center of the pack 🥴.
 
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