The Grom killer that never was- what can I even upgrade?

[Glitch]

This is the HBX 16890SA which I was gifted for Xmas. It’s been really great on my zeee 2200mah shorty packs (they fit terribly, but I made it work), it’s completely stock, and I’ve had 0 issues or breakages including multiple skatepark trips crashing over half the time in below freezing weather.
It’s got full metal threaded body shocks, a decent servo, extra battery and charger and is 3s ready out of the box.

But it ain’t broke, so let’s fix it!

I’ve got redcat volcano tires (mini kaiju tires) already on the way and am about to order a 1/16 erevo wing. Soon, I’ll be buying some metal steering upgrades (lots of slop atm), hex extenders, and hopefully a rocket v2 esc from AliExpress. I’ll be updating this thread as I go along, any questions please ask!

PS yes it’s better than MJX 1/16 hyper go and SCY 1/16

Also looking for servo suggestions?

 

[Glitch]

It is now the worlds first 16890 XL… more info on the way

 

[Saladshooter]

It is now the worlds first 16890 XL… more info on the way

You know I love this RC...... bring it on.

 

[Glitch]

You know I love this RC...... bring it on.

Shocks tuned with 35wt (my first time, not perfect)
Can you guess what car I’m combining it with based on the pile of parts?

If not, full update tmrw!

 

[Glitch]

Update coming soon. The project is going REALLY well

 

[Glitch]

The official reveal…
HBX 16890SA (same as 16889a pro chassis)
XL! I’m using most plastic parts from its longer brother, the hbx t10/2105a 1/14.
Full super parts steel drivetrain. Full metal bodied shocks on the way to replace the shock ones (which are nice, but the shock shaft hits the rubber bump in the top of the shock so it doesn’t fully compress?)

Lots of parts on the way from AliExpress.

It’s going to be severely underpowered with the rtr version of the HW max10 60a

 

[LibertyMKiii]

Deans connector maybe should be swapped for xt90

They have been proven to be a little un-reliable when pushed hard.

 

[Glitch]

Deans connector maybe should be swapped for xt90

They have been proven to be a little un-reliable when pushed hard.

That’s a good idea! Unfortunately I haven’t acquired a soldering iron yet (I know, I know) but I was planning on switching everything I have to IC5 once I do- so I don’t have to void warranties on most cars I buy by soldering xt90s. Thoughts?

You know I love this RC...... bring it on.

It’s going to be a beast. It’s a 16890sa XL and it’s getting an rtr 60 amp hobbywing max10 (unbranded, straight from the factory version of the LC racing max10).
I bought some of the metal pieces but not the kit like you did for a few reasons. I picked up the front and rear wheel hubs as well as a custom (seller actually made a variation on the stock part) steering rack made for an MJX hyper go. The MJX cars mount the servo and steering system opposite side of the hbx, and this 1/14 platform is also opposite from the hbx so the MJX steering parts should fit perfect. I hope this was easy enough to follow lol

— follow up, I want to explain the revised steering bit because it’s interesting. I have one of them already installed in my mjx hyper go and it actually gets rid of almost all of the slop in the steering due to its great design.

Red arrow: This little protruding part acts as a consistently sized “bushing” for the bar/rack to rotate on instead of the stock screw that was there:

That’s a good idea! Unfortunately I haven’t acquired a soldering iron yet (I know, I know) but I was planning on switching everything I have to IC5 once I do- so I don’t have to void warranties on most cars I buy by soldering xt90s. Thoughts?

It’s going to be a beast. It’s a 16890sa XL and it’s getting an rtr 60 amp hobbywing max10 (unbranded, straight from the factory version of the LC racing max10).
I bought some of the metal pieces but not the kit like you did for a few reasons. I picked up the front and rear wheel hubs as well as a custom (seller actually made a variation on the stock part) steering rack made for an MJX hyper go. The MJX cars mount the servo and steering system opposite side of the hbx, and this 1/14 platform is also opposite from the hbx so the MJX steering parts should fit perfect. I hope this was easy enough to follow lol

— follow up, I want to explain the revised steering bit because it’s interesting. I have one of them already installed in my mjx hyper go and it actually gets rid of almost all of the slop in the steering due to its great design.

Red arrow: This little protruding part acts as a consistently sized “bushing” for the bar/rack to rotate on instead of the stock screw that was there:

The stock part, or a generic upgrade part, would have this design where _Red arrow_ rests up against _yellow arrow_ area and a screw with a flat bit acting as the bushing connects them. The screw connecting intruduces the play. It’s a lot worse on the stock MJX hyper go stock steering design (the holes in the _red arrow_ piece are bigger and cause more slop) you can find this online though, I don’t want to spam any more!
Can you tell I’m a little nerdy about this?

 

[LibertyMKiii]

That’s a good idea! Unfortunately I haven’t acquired a soldering iron yet (I know, I know) but I was planning on switching everything I have to IC5 once I do- so I don’t have to void warranties on most cars I buy by soldering xt90s. Thoughts?

I found the EC series connectors to be a pain to solder and get setup, but that is just me. Everyone seems to have their preferences...

 

[Glitch]

Working on shocks again!

I bought the full metal “upgrade” set from HBX to replace the stock ones, because the stock shafts actually hit the rubber pillow at the top of the shock and don’t fully compress!?? Don’t know how this is even a thing lol.

The upgrade shocks also hit the pillow at the top, but I’m going to keep them because the shock cap is an easier to use one piece metal design vs the plastic insert that becomes loose when assembling the shock on the stock shocks.

I have to swap over the plastic rod ends to these new metal shocks because they are actually slightly longer than the metal rod ends. Not sure why!

 

[slick2500]

Deans connector maybe should be swapped for xt90

They have been proven to be a little un-reliable when pushed hard.

Xt90 is overkill XT60 is more than enough for something that small.

 

[Glitch]

Decided to go with the 4200kv 2845 angry snail motor from mjx 16xxx series.
this XL chassis uses a standard mini servo and all the MJX hyper go 14xxx upgrade servos I found would drop right in. Chose the J0022m one and it’s plenty powerful and fast. Using the stock 21t saver with 3 thickish washers but it is really weak.
The build is coming to a close. Rear end buttoned up, waiting on a few metal steering parts and the esc to come in and I’m ready to rock and roll. I ended up giving this thing the full steel drivetrain from the mjx h14bm so that should be bulletproof.
50k front 30k rear in the diffs, the hyper go diffs are sealed and can hold oil. 50wt f/r in the shocks which feels light on the desk.

Got the redcat volcano 16 tires vented and am going to seal the inner holes with superglue because they are too hard to get to with tape.

Probably going to run 12mm hex extended by 12mm initially, we will see if I really need them.


Please leave any questions below would love to share my knowledge of this platform!

You know I love this RC...... bring it on.

Hey there! My build is going great. Almost finished. Did you have binding in your pivot balls? Mine do, specifically front and rear upper arms/links

 

[nepbug]

Got a link for the steering linkage? I've got a 16889a Pro I wouldn't mind making the steering a bit tighter on.

Also, the batteries that you can find that fit in these tend to be poor performers IMO. I've taken to putting 2 batteries in parallel straped together and then strapped into the car. More amps available and longer runtime.

I have thought about using that 14th scale chassis for mine too, and might do it if I ever break my chassis. It's nice for the options of bigger batteries alone!

 

[Glitch]

Got a link for the steering linkage? I've got a 16889a Pro I wouldn't mind making the steering a bit tighter on.

Also, the batteries that you can find that fit in these tend to be poor performers IMO. I've taken to putting 2 batteries in parallel straped together and then strapped into the car. More amps available and longer runtime.

I have thought about using that 14th scale chassis for mine too, and might do it if I ever break my chassis. It's nice for the options of bigger batteries alone!

Steering linkage: https://www.aliexpress.com/item/325...o.order_list.order_list_main.5.a6dc1802f77WkF
Unfortunately, I do not think this would fit a stock hbx 16xxx model.
It is marketed at an upgrade for the Mjx hyper go cars, which mount the servo on the opposite side, so the

Got a link for the steering linkage? I've got a 16889a Pro I wouldn't mind making the steering a bit tighter on.

Also, the batteries that you can find that fit in these tend to be poor performers IMO. I've taken to putting 2 batteries in parallel straped together and then strapped into the car. More amps available and longer runtime.

I have thought about using that 14th scale chassis for mine too, and might do it if I ever break my chassis. It's nice for the options of bigger batteries alone!

https://s.click.aliexpress.com/e/_m0f5wfk
This is the steering linkage- it’s designed for an mjx hyper go but SHOULD work on the 1/14 hbxs (I will find out tomorrow or the next day). I am already using this exact piece on my mjx 1/16 and it remove all of the slop, actually amazed me. Unfortunately it will not fit the 1/16 hbx chassis, the general reason is that the servo is on the other side vs mjx and hbx 1:14 rigs. I’ll send pics tmrw to explain

Looks like I double commented, oops. Had one going on the desktop

 

[nepbug]

Steering linkage: https://www.aliexpress.com/item/325...o.order_list.order_list_main.5.a6dc1802f77WkF
Unfortunately, I do not think this would fit a stock hbx 16xxx model.
It is marketed at an upgrade for the Mjx hyper go cars, which mount the servo on the opposite side, so the

https://s.click.aliexpress.com/e/_m0f5wfk
This is the steering linkage- it’s designed for an mjx hyper go but SHOULD work on the 1/14 hbxs (I will find out tomorrow or the next day). I am already using this exact piece on my mjx 1/16 and it remove all of the slop, actually amazed me. Unfortunately it will not fit the 1/16 hbx chassis, the general reason is that the servo is on the other side vs mjx and hbx 1:14 rigs. I’ll send pics tmrw to explain

Looks like I double commented, oops. Had one going on the desktop

Awesome, I'll look for the upcoming update. It seems pretty cheap to get and experiment with at the minimum, but I'll hold off, there's not a driving need here.

 

[Glitch]

The build is FINISHED! Inside the chassis, I am rocking a Hobbywing max10 60a (which is BUTTERY smooth), Angry Snail 4200kv 2845 motor, and J0022M 4.6kg servo.
All of that is going to be powered by a Zeee 2200mah 3s shorty 50c LiPo pack.

I was impressed with the power of the truck after a 5min backyard test on the storage charged zeee Lipo, but it felt like it was pretty undergeared and has a lot more potential power.
The drivetrain is great, full steel including sealed diffs from mjx h14bm, sounds amazing. Running 50kF, 30kR.

Full metal bodied oil shocks from HBX, filled with 50wt front and rear. I’m feeling that’s it’s too light, might want around 70k at least in the rear. They are more viscosity-hungry than the fronts.

A couple assorted metal upgrades strictly for removing play, not “durability” (aka removing flex for no reason )
Front steering knuckles and steering assembly/ackerman. I’m going to get a 21t metal servo saver soon too, this stocker even with washers is pitifully weak.

I’m rocking an hbx wing mount with an Erevo 1/16 wing. Redcat volcano 16 tires all round.

Controlling this beast will be my FlySky G7P with R7P reciever.

Any questions leave a reply, eager to share my love for this car!

 

[Glitch]

Full test run in about an hour! Cut slots in the chassis to strap down the battery. Reinforced body with aluminum tape and added MJX H16BM roof skid plates.

 

[Glitch]

Update on broken parts at the skatepark:

Wing mount
bumper
center brace rear screw
got some dimples in the body where the shocks are
That's it, the thing held up amazing!

The rear shocks are sagging though. Don't know why.

 

[Glitch]

Fit rear springs from WLtoys 124017 v2 onto the rear shocks. Perfect fit and they are a little stiffer and faster rebound. Still using 50wt all round. Will see if it sags.

 

[Glitch]

Gorilla taped body. The build has been going slowly after the first skatepark trip and breakages. Fitted WLtoys front shocks onto the rear, still using 50wt. They are a little too stiff. Waiting on some more bits from AliExpress to remove slop and make it more powerful…. *cough*5600kv*cough*