Fallen's RC4WD Miller Motorsports #4421

[Fallen]

Well, enough waiting around, I had to start the tinkering. Tinker I did, and will continue for some time. My tires haven't seen dirt yet, and it'll likely be several months before they do.

Speaking of tires, I started by removing the wheels. This required a 4mm nut driver, with very shallow walls to fit in the center cap's recesses. I had a 4mm nut driver that wasn't shallow walled, so out came the grinder. Now it has shallow walls, so I was able to remove the wheels.

That's a knock on this truck. It's lame that it requires a special tool, just to get the wheels off. RC4WD should have included a nut driver for that.

Having the wheels off allowed me to confirm that they are pin drive wheels, and there is a very easy way to change that. Axial SCX10.3 hexes are a direct bolt on. Then just add some hex adapters to the 6 bolt wheels, and you've now got hex drive wheels. You would need to drill out the lug holes in the wheels, and remove the scale brake caliper to make that work. I'm sticking with pin drive for now.



I also confirmed that each shock mount has room for a second shock. Not surprising as the full size truck runs 2 shocks per wheel.

Front:


Rear:


The only time I put power to the truck was to check if the differentials are independently lockable. For my purposes, they are. I used a white paint pen to make marks on the TX where the rear only is locked, and then another mark where both are locked. So you can lock the rear by itself, but not the front. For the front to lock, both have to be locked.



Next up, start to disassemble everything for paint, and rebuild with my Loc-Tite handy. Here's a few comparison photos with my SCX10 Bronco. Remember, the Bronco is 1/7 scale. They're a pretty close match. The Bronco is like a street legal trail truck, where the Miller truck is like its "off-highway" only brother.

[B-MOW71]

Following along to see more!

I am curious to see what good and bad you find along the way!

[bgredjeep]

Yep. What he said.

They sold out so hopefully we'll know how they hold up soon. I'm hoping someone will want to snag all the scale driveline parts so I can pick up the chassis for a build.

[Fallen]

Thanks! I should get more disassembly done today.

The tire foams are nothing special, single stage, open cell, gray foams. I'll likely replace these with Pro-Line dual stage 2.2 foams. The tires do feel pretty nice though. And so far, what everyone suspected has proven true:

If you think there should be Loc-Tite somewhere, it's not there. I wouldn't want to run this truck for more than a battery without some serious disassembly, Loc-Tite application and re-assembly.

[B-MOW71]

Originally Posted by Fallen

If you think there should be Loc-Tite somewhere, it's not there. I wouldn't want to run this truck for more than a battery without some serious disassembly, Loc-Tite application and re-assembly.

That's funny you say that. I thought the same thing about my Marlin. There were loose screws on it when I pulled it out of the box. Immediate tear down was needed!

[smog]

Nice! thanks for the build thread Fallen, interested to see how this goes

[Fallen]

I'm into the rebuild now, after getting this new chassis torn down. I took the axles completely apart too, which had sufficient grease on the R&P, and on the diff lock mechanism.

I'll try to get the bad out of the way first. The truck had hardware everywhere that needed Loc-Tite. The rod ends on the shocks were almost falling off, and also were not Loc-Tited. This truck is a lot of work to work on. Every part that you need to remove, requires you to remove 2 or 3 other parts first.

I'm pretty sure I won't be happy with the stock shocks. I greased the O-rings, Teflon taped the caps and filled them with 10WT oil. They're 100mm shocks. They just feel cheap & rattly.

That said, I really like the truck. Granted, I haven't driven it yet, but I'm confident it will perform well enough for me. The truck is well designed. I treated the truck like a kit that needed to be taken apart first, then built which I enjoy doing. But if I didn't tear this truck down first and make some adjustments, I'd probably be pissed off once I started driving it.

I debated painting the chassis, but decided to do so. It made me have to take the ENTIRE truck apart, and I don't like matte black plastic. The chassis got Krylon Fusion Metallic Dark Metal which is a shockingly durable paint once cured.



The interior got Krylon Fusion Metallic Aluminum, which isn't as durable. But I wanted the interior to stand out from the chassis, and the interior shouldn't meet many rocks.



Certain parts like the brake disks got hit with a Molotow chrome paint pen. Any of my painted parts that are shiny chrome got that treatment.





I'm working my way through reassembly. It's going slow because the build is sort of complex, and I'm trying to minimize assembly, realizing a mistake, disassembly then reassembly. So I'm trying to think through the steps a bit before just throwing everything back together.

[smog]

Stunning, nice job with detailing.

It seems so many 'Rock racing' buggies have been designed in a way that working on them is a hassle.(Twin Hammers, Bomber, Exo Terra come to mind.) I cN be motivation to set it up right the first time. That said I think at one point I could have taken off a twin hammers cage blindfolded if I had to...that rig saw a lot of bench time

[Fallen]

Thanks!

And I suppose that's the price we pay for scale detail. I have a repair to make on my Twin Hammers that I've been putting off because I have to remove the whole cage to make the repair.

The type of RC enthusiast who prefers the ease of a short course chassis would likely not be happy about this Miller Motorsports rig with the amount of work required along with the assumed need to drive this in a realistic way. I also don't think the U4RC crowd would be stoked on this truck, as I really don't think it would survive laps of being driven at 25MPH into rocks.

But I think this truck will stand up to realistic U4 driving. Realistic speeds, realistic jumps and it'll probably do great in the rocks.

My Longxue shocks came in, so I can hopefully get those built up on my next weekend. I also ordered some lights. Those two things along with some eventual tire foams are the only upgrades I have planned for this truck.

Then will come the challenge to see how many battery packs I can put through it before something fails.

[bgredjeep]

The work you've put in looks excellent.

I'm still hoping that someone is going to buy one of these just to strip out all the fancy scale bits (motor, trans, interior, etc) and sell off the chassis. That's all I need to make a sweet u4 ripper.

[Fallen]

Yeah, the chassis on this thing is pretty stout, with lots of support. The tolerances are so tight that once I had painted the cage (2 coats), I couldn't fit it back together by hand. I had to use the hardware to pull the cage pieces back together.

The axles, shocks and electronics would definitely not survive U4RC. But the chassis can handle it.

[Fallen]

Well today I have good news and bad news, and good news.

The good news, the rig is back together and fun to drive. I forgot how big a 2.2 wheeled truck looks and feels compared to a 1.9 wheeled rig. Driving this truck reminds me a lot of my old 2.2 Wraith.

The bad news: 1.5 batteries in and I broke a part in the front axle. The ring gear has 3 tabs that interlock with three tabs on the differential locking sleeve. The three tabs on the ring gear sheared off while I was doing some crawling.


The good news again: RC4WD is sending me a new ring gear under warranty, which they already had on hand. So the Miller Motorsports truck will be back up and running soon.





I've decided to change to hex drive wheels, at least until I get the truck dialed in. Removing those 6 nuts, per wheels is quite tedious just to get the wheels off. Once the truck is set, and I don't need to remove the wheels frequently maybe I'll go back to the pin drive.

Other than that it's just going to be suspension tuning for me. I'm going to leave the stock shocks dry, as they're leaky. Even with greased seals and Teflon taped caps. I'll put oil in the bypass shocks and tune from there. My next step is 10WT in the front and 25WT in the rear. The bypass shocks are LX shocks, 100mm in the front, 110mm in the rear.







I added lights to the front buckets. They're the RC4WD ARB Intensity lights:



https://store.rc4wd.com/RC4WD-ARB-In...et_p_7597.html

They come with two lights. Once you remove the mounting brackets they fit perfectly inside of the front light buckets.



I haven't figured out lights for the rear light bar yet, so I left that off of the truck.

Here's the interior with the overhead switch panel installed.



Once I get the truck driving again, and get the suspension tuned properly I think it'll be a fun truck to have. Like a real U4 truck, it's so versatile in the terrain you can have fun with it in.

I still think the weak point on this truck is the axle housings. Very thin, flexible plastic. I hope someone eventually makes a metal housing for these axles.

[Fallen]

After 1.5 weeks RC4WD got my warranty part to me, and the Miller Motorsports #4421 is back up and running. And it's A LOT OF FUN! When I was into downhill mountain biking, I heard a pro racer describe suspension tuning this way:

Make your suspension as hard as you can, then go faster until it feels soft.





If that's how you like to drive, the Miller Motorsports doesn't disapoint.

If you ever wanted to blast up the technical sections that your trail trucks crawl, this is your truck. The Miller Motorsports prefers momentum to go up and down, and it has the suspension to do both very well.



The only performance upgrades I've done to mine are:

Pro-Line 2.2 XL dual stage foams.
LX 1:10 bypass shocks - 100mm front with 10WT oil / 110mm rear with 35WT oil.
Axial SCX10.3 hexes on the axles.

It can crawl, but it prefers to jump. It's weight balance is quite good, so if you maintain your momentum you'll land clean most of the time.

Crawling this crack didn't work when I tried it slow. But by never coming to a stop, I was able to make it several times.





The truck has a good COG, so when you think it's going to roll, it doesn't. On this gnarly ledge, it lifted the driver's side front tire pretty high, and still didn't roll as long as I kept moving.



Sticky tires and a good COG will apparently take you pretty far. Speaking of sticky tires, this is how my tires looked after 1 hour of blasting around / crawling on decomposed granite. And I'm glad about that. These are nice, soft, sticky tires from the factory.



I'm running a big heavy 5200MAH 3S battery. It lasted an hour. Once it hit LVC the car acted like the pinion was slipping on the motor shaft. But fortunately it was just LVC.

I put several hard rollovers on this truck today, and everything is still running good. Lots of high torque crawling too. No drivetrain damage. I was consistently jumping the truck off of rocks, into more jagged rocks.



My hood panel had one of the lower mount screw holes break out of the lexan, so I cut them off.



I drilled holes into these gussets between cage the members. Now I screw the hood panel to the cage through these holes instead, and the panel feels more secure this way.





This truck can do some crawling, but it really prefers to keep momentum. Which can be difficult to trust when you're used to crawling and being able to slowly monitor each move. But when you learn to trust the truck with speed, it rewards you with fun. Most of the sections I usually crawl carefully with my Bronco, I made easily with the diffs open on the Miller Motorsports by carrying speed and letting the suspension work.

Also, I think my front ring gear breakage was mostly my fault. Trying to lock only the rear was a mistake, which resulted in shallow engagement of the front diff locker. That shallow engagement put too much leverage on the ends of the teeth, which broke them off.

These trucks are back in stock, and well worth the $500 to me.

[durok]

Cool review of an interesting new release!

I definitely like the upgrades you've made, too...

Great to hear how tough it is!

[Fallen]

Thanks! This is now my go-to rig for pretty much any offroading. My Bronco crawls better, and my Twin Hammers does speed better. But the Miller Motorsports is somehow just more fun. Or maybe that's just the newness...

I think I was one of the first of the general public to receive one of these. I got mine on October 11 around lunchtime, which is the day they were supposed to begin shipping the pre-orders.

One small note: I blue Lot-Tited the wheel nuts. They kept coming loose. The Loc-Tite mostly works but I still keep a 7mm nut driver on me when driving this truck.

[ferp420]

Originally Posted by Fallen

Thanks! This is now my go-to rig for pretty much any offroading. My Bronco crawls better, and my Twin Hammers does speed better. But the Miller Motorsports is somehow just more fun. Or maybe that's just the newness...

I think I was one of the first of the general public to receive one of these. I got mine on October 11 around lunchtime, which is the day they were supposed to begin shipping the pre-orders.

One small note: I blue Lot-Tited the wheel nuts. They kept coming loose. The Loc-Tite mostly works but I still keep a 7mm nut driver on me when driving this truck.

check the fit of the hex adaptor if there is any slop it will loosen the wheel not I use tin foil to fill the extra space in the hex so it holds the pin tight and double nut if possible and red loctight that usually works for me lol

And or buy high quality hexs and hope there's no slop

it only takes a tiny bit of movement to loosen that nut

that and a high quality wheel nut like the ones I hate to say it that Traxxas sells make a big difference also

[gein]

Nice job and thanks for the review of this awesome rig!

I may put the trigger on one at some point as a rocks / fast trails companion to my Bomber

[Speedy-Triple]

great review and info... thanks for sharing I thought about getting one of these when came out as I don't have any platform that resembles the features this rig has and the look is great, I just wasn't too sure of the durability and there is a lot of work to fix stuff on it. But it definitely looks like a fun rig that I might keep an eye out for a deal... The scale bits of it are awesome and the performance seems reasonable and capable understanding its not a moonbuggy/rockslayer but a go at a good pace U4 rig.

[themountain]

Thats an awesome review,Fallen! Will you participate in U4 races ?

[Fallen]

Thanks for that tip Ferp. I've never heard or thought of doing that. And I might hit up the LHS today for some Traxxas wheel nuts.

If I did race U4, it wouldn't be with a stock Miller Motorsports truck. Especially not one that I've painted so much.

But the speeds and abuse that a U4RC race would put on a truck are more than I believe this truck can handle. The stock, underpowered electronics / gearing on this truck are a smart choice for this chassis. They limit the speed to what this truck can actually handle. The U4RC guys are running 4S batteries and flying into basketball sized rocks. This truck is fun to drive, but I don't believe it's a competitive U4RC truck.

I think the weak spot on this truck is the plastic axle housings. They're very thin. If a company makes and sells alloy housings for this truck, then I think you'd have a U4RC contender, if they have a "stock" 2.2 class. There are probably alloy axles that can be made to work under this truck now, but that would sacrifice the selectable differential locks.