Arrma Fury 40 MPH Attempt… Till the Spur Gear

The Arrma Fury is the truck to get. Okay, so there are many trucks that you can buy, but the Fury is an amazing bang for the buck. I have a crazy goal to get this truck to hit 40 MPH with a brushed motor. I bought a new motor only to discover that the spur gear was shot. UGGGGGGHHHH! Okay, maybe the truck got me a little furious, and it lived up to its name. However, I did discover how to rebuild the Arrma slipper clutch, which did quiet the drivetrain a lot. I also got some more snap out of it. So, let’s dig in.

If you don’t want to rebuild the whole slipper clutch, you could just buy a new assembly, give a good tug on the end after removing the cover, and then slap in the new one. I decided to rebuild to see how Arrma did it. You can save some money if you just buy the spur gear.

Whatcha need

The tools that came with the kit. I am not joking one bit! This truck claims to be ready to run, and it is the most ready to run vehicle I have seen. The thing is amazing. The wonkey and weird tool that looks like an information extraction device.

I plan to haul that tool out and play with it each time a boy picks up one of my daughters. I will say in a very authoritative voice, “She’ll be home by 10, right? You really don’t want to know what this device can do.” I doubt that Arrma built the tool to be an intimidation device, but I have always liked the Swiss Army knives and the Leatherman tools. Multipurpose is the way to go. So, kudos to Arrma for inventing one of the weirdest-looking tools ever!

Thankfully, weird looking is not always bad. I mean, my wife keeps me around for more than squishing bugs or oil changes. This is a tool you want in your transmitter bag. I was able to take the slipper clutch out, apart, clean it, and put it back together using only the tools of the kit. When Arrma says RTR (ready to run) they mean Ready to RC!

I give some major kudos to Arrma or Horizon Hobby for this kit. This truck is a great contribution to the hobby. This truck is durable and really easy to work on. This might be the Honda of the RC world.

Let’s Fix This Noise

First, you want to take the two screws loose for the cover. There is one of the top and one on the bottom.

Second, you just pull the cover forward and slide the cover so the tab is loose.

Third, you pull on the exposed black nut and the whole assembly should come right out.

Fourth, you just pull on the nut for the slipper clutch. The whole gear should pull straight out. This is so cool. If you want to change gear ratios on the fly, you can have a few pinion gears (they go on the motor) and some spur gears. If you arrive at the track and want the truck to have some more umph out of the turns, you can put a bigger spur gear on it to give it more torque. If you want more power down the straights, just put in the smaller spur gear to give it more top end. You can swap this out in a matter of minutes. If you want to get nitpicky, then start messing with the pinion gear. I love how Arrma designed this.

Fourth, hold the spur gear and use the tool to get the plastic nut off the end of the slipper clutch assembly. It is not very tight.

Fifth, pull the slipper clutch apart and see if there is any dirt or grime wedged in there. Clean it, and then reassemble it. Note that the nut has a flanged end. The flat tab/flanged side goes toward the spring.

This is the order and direction that the parts need to be when you put the clutch together.

Note the order, and the direction of the shaft.

Notice that there is a key or a pattern that you use to click the pressure plate into the drive shaft. You will hear it click

Here you see where the nylon/plastic slipper plate clicks into the spur gear. You will feel it click into place.

The parts arranged after assembly. The slipper plate and the pressure plate might come loose, but you can spin them into place before you tighten the flanged nut all the way down. You’ll hear it click, but just make sure everything is seated before putting this back in the truck.

Why the slipper clutch? Well, as you get a more powerful motor, the more stress there is going to be on the drive train. So, this allows some slipping when you initially hit the power. The tighter the nut against the spring, the less slip you will allow. The looser the gear, the more it will slip. As you play with the tension, you can get it to brake a little more smoothly or less smoothly, where you might want the back end to drift out a bit. If you set it too loose, then you are going to lose power to the rear wheels. This is a subjective thing where you play with the tension to get the truck performing how you want it.

I got the truck back together. My GoPro GPS read over 100 mph! That is awesome, but really not true, the GPS was not talking the satellites very well. When it seemed to communicate better, I was in the 30MPH range, which I think is correct. Unfortunately, the GoPro battery died, and I did not get any more footage. My butt dyno says about low to mid 30s MPH.

What I learned

Maintenance is a bummer, but necessary. Unfortunately, eventually your play dates end with a work date. Things break, and they need some attention. Life is not a cruise control of fun. Things and relationships need maintenance. RC as a hobby is a reminder of this truth. If you want the good days, put in the maintenance work to get those good days. Think of this as another way of bonding.

Overcoming challenges builds perseverance and confidence. RC is a very small-scale way to build confidence in new skills. If you get frustrated, you can leave the car on the table, take a break, and come back to it. However, eventually, when you sort out the problem, you learn new skills. You can learn that maybe the problem is not as big a deal as you initially thought. You realize you do have the skill set to problem solve. You also learned the skill to persevere through something that may have been overwhelming, but now you see it is not that overwhelming. Perseverance pays off. You have the skills to solve this.

If you watch Jay Leno’s garage, he quotes the common proverb, “Busy hands make a happy heart.” The point is that as one has purpose, one finds contentment. This is not just RC, but I have seen this while driving. I have experienced this with motorcycles. I have experienced this with home projects. I am sure that you can think of an example or two. The point is that as you rebuild something on the RC car/truck and it works, you have satisfaction. It provides a goal and a purpose.

Ultimately, I learned in this little project that you don’t have to spend money. You don’t have to have more gear (Boy, am I ever a gear guy!). Sometimes, all you need to do is take something apart, inspect, clean it, and put it back together. Now, I have figured out how the Arrma slipper clutch works.

Conclusion

So, if your Fury is making you furious, slow down before you start throwing money at the problem. That squeal or chatter is often just a worn spur gear or a slipper clutch that needs a little love. And even if you do end up replacing parts, taking the time to open things up, clean them, and reassemble them might be all that is needed. Worst case, a new spur gear is under 10 bucks. I learned that the Fury really is a well-designed truck. Arrma made a Ready to RC vehicle.

So don’t be afraid to dig in. You may save some money, you’ll definitely learn something new, and you’ll come away with a Fury that’s smoother, stronger, and ready for the next adventure.

Thank you so much for taking the time to read this. Do you have any experience with this truck? Until we meet again, be safe, look for opportunities to be generous, and get outside.