Yeti Jr. upgrades

[MT-Mark]

Both my yetis continue to run beautifully and they are still 2 of my most robust favourites. With axial discontinuing both the RR and TT I’m in the same place as others and both need a new body ASAP. Has anyone tried fitting any other 1/18 short course body to their Trophy Truck? Mine is now 90% shoe goo and drywall tape and really needs replacing. Original axial part number was AX31528 but that’s not much help I guess!

 

[MT-Mark]

...like the WLtoys A-969. At less than £10 I might just take a punt and see what happens.

 

[rampage]

I know this thread is pretty much dead, but I just picked up a Yeti Jr. Score for like $80 new in box. Just for something to throw in the car and take with me.

I'm using this brushless setup, but the ESC is absolute garbage and I'm going to replace it with this Hobbywing unit instead.

I've also installed the rear locker. Steering servo was replaced with a spare PowerHD 1810MG I had laying around.

Here's some of my questions. I know it's been a while since this has been discontinued and aftermarket has dried up considerably, even with the Can Am still available, but mine spends more time on its roof than on its wheels, even with the throttle endpoints dialed back to 50%..

1) What pinion would you recommend for the 4800kv motor? It gets crazy stupid hot.

2) What are the options for front suspension arms that aren't aluminum? The stock ones are ridiculously flexy and I have a feeling that the arms 'tucking' in is part of the problem with it rolling. There's so much play in the front arms..

3) What'd you guys use for servo mounts? I'm using the servo mount from an old Radio Shack ProPulse and it works good but I'd rather have a mount that didn't obstruct the top of the servo so can mount the ESC there.

Overall I think this is a great little truck. I've got the full-size Yeti TT and both are fantastic. Just seems like they really cheaped out in some areas of the design.

 

[Fallen]

Unfortunately, the only companies who make upgrades for the Yeti Jr are GPM and Axial. There's a few neat items on Shapeways too.

The drivetrain upgrades are definitely worth doing. For the differential lockers, you want Axial. The GPM ones are a bit too large for the housings and they rub. They wear in eventually, but the Axial ones are smooth from initial installation.

As far as the pinion gear, I don't remember what I run. I have the Holmes Hobbies 380 Revolver 2200kv in mine. My Yeti Jr is too fast for its own good, and that motor has never been more than warm.

 

[rampage]

Unfortunately, the only companies who make upgrades for the Yeti Jr are GPM and Axial. There's a few neat items on Shapeways too.

The drivetrain upgrades are definitely worth doing. For the differential lockers, you want Axial. The GPM ones are a bit too large for the housings and they rub. They wear in eventually, but the Axial ones are smooth from initial installation.

As far as the pinion gear, I don't remember what I run. I have the Holmes Hobbies 380 Revolver 2200kv in mine. My Yeti Jr is too fast for its own good, and that motor has never been more than warm.

Yeah with the cheap brushless kit I've got in mine it basically implodes at like half throttle. I think right now I've got my endpoints at 45% just so it tracks straight and doesn't go cartwheeling down the street because the front arms are so flexy it couldn't keep itself going straight.

I think I'll just run my current pinion (mostly because it took forever to get the gear mesh right and I don't want to deal with that again) and if I blow up this 4800kv motor, I'll just buy one that doesn't suck.

I went ahead and ordered the GPM front arms too. I'm not usually one for aluminum parts but good lord the flex in the front arms is bad. If there was an option for RPM arms I'd gladly go with those but it is what it is.

Ordered the new ESC too. The "readytosky" ESC is terrible. Even with the programming card in-hand, it's got so much delay in throttle response and basically no torque. It's terrible.

 

[rampage]

I installed and programmed the Hobbywing ESC. And proceeded to instantly snap a rear axle shaft. :lmao:

This thing's turning into a little money pit. And I'm completely okay with that.

 

[Fallen]

Once the entire drivetrain is metal, it's surprisingly durable. The chassis and suspension parts take quite a beating.

The GPM and Axial drivetrain options both work, except for the aforementioned differential lockers.

But the stock plastic in the drivetrain definitely won't survive brushless power.

Until that whole drivetrain is metal, you probably won't get through a whole battery with a brushless system.

 

[rampage]

I bought a Can Am off eBay that was an "Amazon return" for an insanely good price, missing the TX (which is fine) and the charger (which is also fine) and it was reported to have a broken front universal. It also has a broken axle shaft. So somehow the original owner managed to snap a universal and an axle shaft with stock brushed power. Haha.

I have no idea how Axial thought that was a good idea.

 

[rampage]

Okay, quick question on binding.

I was told the RX in the Can-Am is DSMR, so it should bind to my trusty DX4C.

When I try to put the vehicle in bind mode, I get a rising tone and then about 2 or 3 seconds later I get the rapid-flashing red LED. That's how it should be, right? But then about 5 seconds later the steering twitches and the ESC appears to reboot itself, whether or not I start the bind process on the TX. It never completes the bind process.

Is this RX/ESC toast?

I'm wondering if someone tried to run this on 3S. That'd explain the broken axle shaft and universal and would explain why the ESC/RX appears to be toast.

 

[Fallen]

Interesting find: The Traxxas 380, 27t motor fits in the Yeti Jr. chassis. It's a bit longer than the stock motor, and slightly less turns (37t VS 27t).

It even has the same size pinion gear shaft. It bolts right up, and should have better torque and speed than the stock motor (of which I've burned two).

 

[jakehinds]

So sad to see this thread die! does anyone know WHY Axial discontinued the Rock racer and trophy truck? An inherent issue or just lack of interest? There's a rock racer near me i want to buy, but not sure if it'll be a dead end on parts....

 

[soze]

So sad to see this thread die! does anyone know WHY Axial discontinued the Rock racer and trophy truck? An inherent issue or just lack of interest? There's a rock racer near me i want to buy, but not sure if it'll be a dead end on parts....

It should be mostly the same chassis-wise for parts. I think the biggest issue would be finding the replacement parts for body/cage work for the Rock Racer.

 

[iholmes]

So sad to see this thread die! does anyone know WHY Axial discontinued the Rock racer and trophy truck? An inherent issue or just lack of interest? There's a rock racer near me i want to buy, but not sure if it'll be a dead end on parts....

I still run my TT on the backyard track at least twice a week. Like Soze mentioned, most parts can be found for the can-am. I find myself driving this much more frequently than any of my other trucks. Recently I've dropped a read locker, metal axle shafts and rear driveshaft. I run 2s mostly but 3s on occasion with a hobbywing quicrun and the stock motor.

 

[jakehinds]

I still run my TT on the backyard track at least twice a week. Like Soze mentioned, most parts can be found for the can-am. I find myself driving this much more frequently than any of my other trucks. Recently I've dropped a read locker, metal axle shafts and rear driveshaft. I run 2s mostly but 3s on occasion with a hobbywing quicrun and the stock motor.

Well, glad to see this thread isn't completely dead.... I'm still intrigued, and I'm pretty sure I'm going to try one LOL.
I have a guy selling an old rock racer near me, but someone in one of my RC FB groups said the old rock racer had some problems with long steering links causing binding (fixable), and links are too tight around the ball studs(prob not fixable). Have you guys seen these issues before? He said they fixed it on the new Can Am's.

My options are to buy this used rock racer for $100 shipped, or look for a can am, then buy the Yeti jr front bumper, body, and cage. I've found the front bumper and cage, but no luck on the body..... I may just have to buy this used rock racer and use it as a second rig/donor rig... Thanks guys

 

[iholmes]

I haven’t had any binding issues on the steering but I have the TT are dropped in a savox Servo within the first few months. That thing is super noisy but never given me any issues.


Sent from my iPhone using Tapatalk

 

[IntrepidMercians]

I bought one of these recently as a clearance sale on eBay, it's compact and good fun but could do with some improvements:

1. The spring rates seem too high for it's weight so it has a jiggly ride
2. The wheels are a bit too small which means it grounds out easily

The previous two factors mean it struggles for traction on bumpy terrain. I don't think locking the rear axle is the first solution I'll try - instead look for some larger diameter wheels.

I've tried different mounting points and preload amounts for the shocks but it doesn't make much difference. I have also drained and refilled them with 300wt oil because they were either empty or part-full.