Smoked slipper clutch

[trxrdr17]

Hi all,

I have a Trx4 kit I built and modified with brass weights, steel wheels, upgraded tires and foams. The kit is powered by a HobbyWing Axe ESC and brushless motor kit for crawlers. The kit probably has 5-10 hours of run time and I recently noticed a whining noise along with power loss. I immediately thought of the slipper clutch. After getting everything apart, I found the slipper clutch to be very worn (shiny, circular indentation from the washers with friction material coming out from the outer sides). I’m sure I adjusted the slipper clutch accurately when I built the kit initially, did the extra weight take its toll? Do I need to upgrade the slipper clutch to a heavier duty type clutch? Delete the slipper clutch all together?

Any input is helpful, thanks.

 

[23drumerboy]

Hi all,



I have a Trx4 kit I built and modified with brass weights, steel wheels, upgraded tires and foams. The kit is powered by a HobbyWing Axe ESC and brushless motor kit for crawlers. The kit probably has 5-10 hours of run time and I recently noticed a whining noise along with power loss. I immediately thought of the slipper clutch. After getting everything apart, I found the slipper clutch to be very worn (shiny, circular indentation from the washers with friction material coming out from the outer sides). I’m sure I adjusted the slipper clutch accurately when I built the kit initially, did the extra weight take its toll? Do I need to upgrade the slipper clutch to a heavier duty type clutch? Delete the slipper clutch all together?



Any input is helpful, thanks.

This is not scientifically speaking but in my head initially, My thoughts are that the added torque from the new motor mixed with the added weight simulated a false load on the slipper clutch making it think that the motor was trying (excuse me as I know the slipper clutch does not have a brain so let's say that I'm thinking lol)... Too much torque extra weight etc pushed through even a thoroughly tightened down / slightly used prior slipper clutch with no problem I noticed that even with my trailer master 550 27t and two speed conversion on my sport, even a heavily tightened clutch will wind sometimes on heavy climbs etc but my sport weighs roughly 12 lb.... Any idea what yours weighs??

Also could just be time if you bought the truck had it awhile then upgraded it and put 5 to 10 hours on it nobody here doubts your slipper clutch adjustment, however maybe there's a heavier duty friction material out there that you can slap on a Traxxas spur gear? I know people who strictly crawl that claim locking or deleting the slipper putting a spool there instead for direct full power at all times is one of the best upgrades they ever did especially alongside added weight bigger motors etc

Read-Up! Mod-On! Crawl EXCESSIVELY!

 

[23drumerboy]

This is not scientifically speaking but in my head initially, My thoughts are that the added torque from the new motor mixed with the added weight simulated a false load on the slipper clutch making it think that the motor was trying (excuse me as I know the slipper clutch does not have a brain so let's say that I'm thinking lol)... Too much torque extra weight etc pushed through even a thoroughly tightened down / slightly used prior slipper clutch with no problem I noticed that even with my trailer master 550 27t and two speed conversion on my sport, even a heavily tightened clutch will wind sometimes on heavy climbs etc but my sport weighs roughly 12 lb.... Any idea what yours weighs??

Also could just be time if you bought the truck had it awhile then upgraded it and put 5 to 10 hours on it nobody here doubts your slipper clutch adjustment, however maybe there's a heavier duty friction material out there that you can slap on a Traxxas spur gear? I know people who strictly crawl that claim locking or deleting the slipper putting a spool there instead for direct full power at all times is one of the best upgrades they ever did especially alongside added weight bigger motors etc

Read-Up! Mod-On! Crawl EXCESSIVELY!

My other thought is that if you had the slipper clutch a while and it had the locking nylon nut off of it more than once or twice chances are it's wore out and needs a new net put on so it could have very well worked itself loose causing excess slippage which quickly burned out The clutch?

Read-Up! Mod-On! Crawl EXCESSIVELY!

 

[trxrdr17]

This is not scientifically speaking but in my head initially, My thoughts are that the added torque from the new motor mixed with the added weight simulated a false load on the slipper clutch making it think that the motor was trying (excuse me as I know the slipper clutch does not have a brain so let's say that I'm thinking lol)... Too much torque extra weight etc pushed through even a thoroughly tightened down / slightly used prior slipper clutch with no problem I noticed that even with my trailer master 550 27t and two speed conversion on my sport, even a heavily tightened clutch will wind sometimes on heavy climbs etc but my sport weighs roughly 12 lb.... Any idea what yours weighs??

Also could just be time if you bought the truck had it awhile then upgraded it and put 5 to 10 hours on it nobody here doubts your slipper clutch adjustment, however maybe there's a heavier duty friction material out there that you can slap on a Traxxas spur gear? I know people who strictly crawl that claim locking or deleting the slipper putting a spool there instead for direct full power at all times is one of the best upgrades they ever did especially alongside added weight bigger motors etc

Read-Up! Mod-On! Crawl EXCESSIVELY!

Thanks for all the info! I upgraded the rig pretty much right away, I had an ultimate goal in mind with it. My gut was telling me that the added weight and more powerful motor was the likely cause. It weighs 8.8 lbs according to the bathroom scale, not sure where that lands it in terms of crawler weight? Would adding a spool put the ESC/motor at any sort of risk?

 

[HumboldtEF]

First did you simply try tightening up the nut holding the slipper assembly together?

If its toast personally I'd replace the clutch pads and maybe use a new lock nut if its worn. From there you can decide if you want to just tighten it to the point its nearly locked or like the manual states.

I have a similarly heavy TRX4 running a revolver and have had no slipping in the 3+ years of use. My guess is your clutch was simply too loose.

Eliminating the slipper may lead to breaking other parts easier, its job in crawlers is to be the weak link. By eliminating it you risk making other parts (that may break instead is just slipping) the weak link. It should however only slip when you're bound up and not under normal use.

Eliminating the slipper isn't all that uncommon though, once you learn to listen for what your rig is doing you will know when your rig is getting bound up and when to back off.

 

[amigaman]

If you have the shiftable gears the slipper is useless as it will work in only one of the two settings.
So in case of a single gear car i'd replace the pads and set it up like told in the kit manual, on a shiftable gear car it's better to replace it with the slipper eliminator plates.

 

[HumboldtEF]

If you have the shiftable gears the slipper is useless as it will work in only one of the two settings.
So in case of a single gear car i'd replace the pads and set it up like told in the kit manual, on a shiftable gear car it's better to replace it with the slipper eliminator plates.

Thats not my experience with the 2 speed. The slipper doesnt just not work in 2nd. What are you talking about?

If the tension on the slipper is setup right you're unlikely to have any issues.

 

[trxrdr17]

First did you simply try tightening up the nut holding the slipper assembly together?

If its toast personally I'd replace the clutch pads and maybe use a new lock nut if its worn. From there you can decide if you want to just tighten it to the point its nearly locked or like the manual states.

I have a similarly heavy TRX4 running a revolver and have had no slipping in the 3+ years of use. My guess is your clutch was simply too loose.

Eliminating the slipper may lead to breaking other parts easier, its job in crawlers is to be the weak link. By eliminating it you risk making other parts (that may break instead is just slipping) the weak link. It should however only slip when you're bound up and not under normal use.

Eliminating the slipper isn't all that uncommon though, once you learn to listen for what your rig is doing you will know when your rig is getting bound up and when to back off.

I like the idea of keeping the slipper clutch as I let inexperienced RC drivers run my rig from time to time. Is there a heavy duty option or just replace with stock friction material?

 

[23drumerboy]

I like the idea of keeping the slipper clutch as I let inexperienced RC drivers run my rig from time to time. Is there a heavy duty option or just replace with stock friction material?

Every body. And their brother's dogs say that no slipper cause "EXTREME" DRIVETRAIN WEAR!! [emoji33]. I BEG TO DIFFER!

Yes, with a 10-ish lb R4stler with 1/8th scale power, and tops out at anywhere between 65-80 mph.... U MIGHT want a slight slipper loosening from "full-tight". . . .

However, with crawlers, i HONEST-TO-Jihad! we ain't moving NEARLY fast enough for the "slip-to-save" clutch to even matter!!! Yes, sure, YOU tend to wedge two opposite tires between two rocks and MASH/PIN that throttle down to get "un-stuck"...but THAT SITUATION is why models have slippers..along with tarmac-hot-tire-WOT-launches from 0-WOT mph ALLLL DAY, EVERY DAY WITHOUT rest to u-joints, etc.....but, i

Swear on all things deserving.... Try locking the slipper FuULLY, (not breaking the threads off of shaft, but turn the nut till she stops then grit ur teeth and give a lil "eeet" as i call it! (Approx. 1/8-/1/16 of a full 360°.) Call it 364.67°?!

Lol!
I digress.

This will give u somewhat of an idea, as to whether or not your drivetrain is suffering when "bound up", or at all with YOUR rig/YOUR driving style...then if u feel torque-to-rocks is wayyy better, buy the spool!

My trx4 would probably be PERFECT with no slipper, just throttle control, wisdom, and a few spare spur gears to boot! U know...just in case the fun is cut short?

HIGHLY doubt it.! Try nd report back here. If u do tighten her down to haides




Read-Up! Mod-On! Crawl EXCESSIVELY!

 

[amigaman]

Thats not my experience with the 2 speed. The slipper doesnt just not work in 2nd. What are you talking about?

If the tension on the slipper is setup right you're unlikely to have any issues.

It depends on how you adjust it.
But what you do, in one setting the slipper can't help you.


If you set it so that it protects the system in low, you'll notice it slips a lot in high, because the motor needs more torque to move and accelerate the model. That'll burn up the slipper fast.


If you adjust it for high, it'll never slip in low, breaking the driveshafts.


A driver that looks for the model (as it's a crawler, not a basher, you're likely not that far away) won't break anything with the eliminator plates in either gear. At least i and a handful of people i know didn't. From fun drivers, kids, scalers to competitors.

 

[Tiredmechanic]

It depends on how you adjust it.
But what you do, in one setting the slipper can't help you.


If you set it so that it protects the system in low, you'll notice it slips a lot in high, because the motor needs more torque to move and accelerate the model. That'll burn up the slipper fast.


If you adjust it for high, it'll never slip in low, breaking the driveshafts.


A driver that looks for the model (as it's a crawler, not a basher, you're likely not that far away) won't break anything with the eliminator plates in either gear. At least i and a handful of people i know didn't. From fun drivers, kids, scalers to competitors.

I run a eliminator kit on my truck with 0 issues but ill chime in on this.


What your saying does not make sense. The slipper will slip at the same load based on setting regardless of gear. The point isnt to have the slipper always slip its to have it slip under a load that risk drive train. That limit is a constant value regardless of gear it just easier to reach that value in 1 gear vs the other. The slipper is pre trans so its going to slip at a constant set value based on drive train load vs motor input. What your saying would be if the slipper was post trans where the 2 different output settings would be taken into account.

 

[meatmonkey]

The added gear reduction of 1rst gear takes load off of the spur gear due to the additional gear reduction downstream.

As an example, I put the Traxx kit on one of my Trx4's and on the first trip out into wet dense snow noticed that my slipper clutch, that I normally dont notice or hear, would slip fairly easily if froggy with the throttle in high gear, but didn't seem to slip at all in low gear. So gear ratio certainly effects the slippers ability to do its job.

It seems with the Bellville washers, instead of a coil spring, the "tuning window" of the slipper is fairly narrow. Like 1/4 turn is the difference between too loose and too tight in my experience.

Sure, the Trx4 drivetrain has proven its strength to the point of nobody suffering premature failure due to eliminating the slipper. I gotta think though, that utilizing the slipper appropriately helps take shock load off the drivetrain and leads to longer service life of all the gears and shafts.

 

[amigaman]

I run a eliminator kit on my truck with 0 issues but ill chime in on this.


What your saying does not make sense. The slipper will slip at the same load based on setting regardless of gear. The point isnt to have the slipper always slip its to have it slip under a load that risk drive train. That limit is a constant value regardless of gear it just easier to reach that value in 1 gear vs the other. The slipper is pre trans so its going to slip at a constant set value based on drive train load vs motor input. What your saying would be if the slipper was post trans where the 2 different output settings would be taken into account.

It is exactly the other way around.
As the slipper is on the motor side, before the shifter, the "slipper set point" is on wildly different setpoints, speed and torque wise, because those are seen at the wheels, not the motor.
In low gear, the slipper set point gets stepped down so you get a lot of torque on the wheels before it slips.
In high gear, you get more speed and thus less wheel torque for the exact same slipper setting.
So the slipper does either "protect low, burn up in high" or "protect high, destroy low".


And, as meatmonkey said: there's almost no usable range on the setting, even if you do a single speed setup. About an eighth turn between "burns up" and "never slips" is hard to get correct.

 

[OSRC]

Definitely sounds like it was on the loose side.. 3 TRX's and a TRX6, all with lots of brass. Never had a slipper issue. Agree that the adjustment range is somewhat narrow, I usually set per the manual, and then give it another 1/8 of a turn. I just want it to give if the truck is bound up which is what it's there for.

I'd just crank it back down tight and keep running it unless it's completely destroyed. In that case, pick up the stock parts and rebuild, stock bits can handle it fine. You can crank it down pretty tight, it'll basically act locked out if that's the route you want to go.

 

[Den72]

When I got back into this hobby, I wasn't nearly as familiar with slipper clutches. I quickly had a crash course in adjusting when I got to the trail. Luckily I had the wrench with me and access to the screw without having to tear everything apart.

I made the adjustments based on the terrain I was in. When it stopped slipping I new I was good. :lmao: