ARRMA’s Slipper Clutch Upgrade
Introduction
One Monday afternoon, my buddy calls me and says, “Hey, you still following Baja?”
“Yeah, I still tune in and watch the race start. I love the Trophy trucks. I can listen to them roar all day. Then the dudes in the VW bugs just love being punished! I admire those guys.”
“How about we plan to ride down there, camp the night before, and watch the beginning of the race?”
“Yeah, let me put in for vacation and make this happen!”
The reality is, trophy trucks are cool. We might think that we have to go to Baja to see them. We can thank Mickey Thompson who owns a little tire company, for bringing these beasts closer to home. He figured out that you can take the excitement of Baja, and put it in a stadium. He wanted to share, “A chunk of Baja.” Hence, the short course truck or stadium trucks. His vision was to take that desert truck and make it for all to see. This is not only in the full stadium, but even in the RC world. Too bad Mickey never got a chance to see what he created because he was tragically taken from us too early.
RC Short Course Trucks
Short-course trucks are not just toys. No, it's about being strategic with suspension tweaks to impact lap times. You see firsthand how little changes impact the performance of the truck. This is exactly why guys pre-run the course in Baja. This is what the full-scale trucks are doing. RC allows you to experience this strategy on a fraction of the budget. If only Mickey Thompson could see what his movement spawned.
RC allows us to do more than just play games, but to really build something. You know, even your ready-to-run kits have near-endless tuning abilities. The short course scene keeps bringing me back to the Arrma Fury Short Course Truck. This thing is a great bang-for-the-buck truck. I am still seeing how close we can get to the 40MPH mark. I upgraded the spur gear and put the slipper clutch together so the truck can handle some more beans. This is really a significant upgrade for the truck because now I can run some serious power through the red truck. We can move it beyond the brushed system and go to a real brushless system.
Building the Drive Train
First, what Spur gear did I use? This is the gear that I ordered through A Main Hobbies. If you want to support my efforts you can use my Amazon Affiliate link and buy the gear through Amazon. I know that this gear works.
(These slipper clutches are easily removed. You literally just pull it out. You do not even need to remove the motor. Here you see the slipper clutch with the new gear sitting on the mat. Yes, I use white lithium grease.
Installing the gear is easy. You simply take the slipper clutch apart (remember to lay out the pieces as you remove them). You will notice that the end caps simply pop off. The hardest part is getting the teflon plate to stay put when you put it back together, but this is a 10-minute job tops.
What I love about this drivetrain is that down the road, if there are different gears, you can change your gear ratios on the fly. You can have a couple of slipper clutches with different spur gears. I would just buy the slipper clutch kit and wait for the spur gears to wear out. The plastic one will wear out in a couple of months with steady usage.
(Once you take off the end nut, you just pull things apart. You will see how it all fits together. Remember to take the end caps off the old spur gear to attach to the new spur gear.)
So, what is the slipper clutch, and why do you need it? A slipper clutch is a part of the drivetrain that lets the spur gear slip under heavy load. If the clutch is very tight, then there is less slip. If the clutch is loose, then there is going to be more play.
This clutch protects the spur gear and transmission from sudden torque spikes. When your truck lands from a jump or hits a rough surface, the slipper clutch absorbs some of that shock instead of grinding gears.
This will allow the truck to dig into dirt better. If there is a little play, then the wheels don’t just dig into the dirt. When you give it the beans then it will slow down the speed at which the wheels spin. The motor will spool up, drivetrain engages a little more slowly, and the wheels dig a little slower, gaining more traction.
(This new gear fits together in this order. The hardest part is keeping the teflon plate seated in the spur gear. You’ll get it. It just requires some patience.)
Basically, you could say that the slipper clutch is like a manual traction control. If you want the wheels to slow down a bit to gain traction, then keep the clutch loose. If you want the rear end to drift around a bit, then keep the clutch tight. This is another way to tune the truck to get the power down. Simply stated the looser the clutch the less the rear wheels will slip. There will be a slight delay for the wheels to catch up to the motor’s RPM. If you want the back end to drift more then tighten the clutch so the power hits the wheels much quicker. This delay is a fraction of a second. However, you will notice traction differences as you loosen and tighten the clutch.
Another nice thing about the slipper clutch is that if you let a newbie drive the truck, you can set it to be loose. That way if the person slams the truck from forward to reverse or vice versa, the driveline will not take such a lashing.
The beauty of this is you can feel like the manager of a high-dollar race team on a blue-collar budget. This is why RC is fun. You learn how vehicles work, and you don’t have to pay the big bills. If you have a bad crash, you don’t have to wait for the tow truck to come. You just pick up the truck and head home.
Conclusion
The unfortunate thing is that when the time came for us to ride down to Mexico to watch the Baja launch, the cartels were kidnapping Americans. We figured that the stress was not worth it. So, the ride never came to fruition. I did not get the chance to watch the live launch of the Baja 1000. However, I can reenact it with my son each time we take out the short-course trucks. This is why RC is a great hobby. RC gives you a reason to get outside and teaches you how vehicles actually work. Not to mention, this is something that you can share with your kids. The best part is that mere mortals can afford to run a truck or two.
In the meantime, I will just keep playing with the scaled-down versions. They are still a joy to watch perform.