Toasted Spur gear...

Welcome to RCTalk

Come join other RC enthusiasts! You'll be able to discuss, share and private message with other members of our community.

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.

SkyMaxx

RCTalk VIP
Supporter
Active Military
Messages
8,360
Reaction score
11
RC Driving Style
  1. Bashing
I thought I'd share this with those of you who have spur gear issues. Keep in mind that the spur gear is designed to be sacrificial and to protect the drive train.

At my last bash session with El Pirata (aka Master of Disaster), I managed to smoke my spur gear, but not in the typical manner that they get smoked. Check it out.

The Savage turned out to be better than my late night inspection from before. If I go on the cheap (meaning no upgrade) my total cost for damages will be about $4. The clutch shoes were not any more burnt than they have been. The water in the clutch bell actually saved them from any major work. The spur gear on the other hand is toast (and that is all I have to replace). The rest of the drive train is in fine working order. Tranny and diffs all saved by a properly set up spur gear (lesson here for everyone).

Here is the inside of the spur. Note the shards of the little friction pad burned/melted into the outer ring of the spur gear.
DSC01906.JPG


Here is the outside of the spur. Note the meltage around the bushing. Going to need a chisel to dig that thing out of there.
DSC01907.JPG


Finally, note that none of the teeth are missing or screwed up. The friction segment of this slipper clutch did exactly what it was designed to do. It ate itself before letting the rest of the drive train get torn up.
 
Wow that is pretty damn odd. I mean usually the teeth go?? Were you running your slipper a little loose??
 
So what happened?

It looks like the slipper was too loose.
 
yup, that's been cooked. how loose did you run the slipper clutch? i've run almost two gallons thru my s-25 when it finally spit out a tooth but the slipper clutch didn't show too much wear. that was with it set about a quarter turn loose. you must be running some serious hp through your savage.
 
The slipper was set just right. The problem was too much torque and lots of water. The water made the clutch more slippery than normal...and the torque just made the spur rotate. The heat build up eventually fragged the slipper friction pad and melted the rest of the gear. I got to peel a nifty little melted plastic washer from the axle that supports the spur gear. The bushing was not only melted into the gear but sunk and further imbedded itself thanks to the pressure from the slipper spring.

Note to self, watch out for water and keep a spare handy. Also replace that stupid bushing with a bearing.
 
Damn man, thats some serious torque. I love that poop!!!!

One time, when I blew a gear in my Tmaxx (stock plastics), the spur wouldnt rotate at all. So of course, me like an idiot, kept hammering the throttle. Well, a couple seconds into that, I broke off a couple of spur gear teeth. That was the trigger, from there, like a normal guy would, I still kept hammering the throttle. Well, like a fountain of black rice, every tooth removed itself. And I was left with a nice smooth and round spur hehehe
 
Holy crap dude what did you do dang.....Nick
 
Bearing

Why swap the bushing for a bearing?
 
The bushing generates heat from the washer that supports the spring. As the gear rotates, that heat builds up. Not a really big deal except it can get coupled with other heat build ups and end up embedded in the plastic of the gear (see picture above). The bearing on the other hand allows for some rotation and helps with keeping the heat down (less friction means less heat).

This isn't a show stopper by any means, but one more little tidbit that will make the truck run a smidge more smoothly.
 
Originally posted by SkyMaxx
Note to self, watch out for water and keep a spare handy. Also replace that stupid bushing with a bearing.

Seems like a familiar scenerio..... Or was that a dogbone I gave ya?

Play in the water, get a boat.
 
LOL...You gave me a dogbone and a spur. Both from the same kind of issue...too much water/mud and too much power. Got to love these little monsters.
 
Originally posted by El Pirata
He's got a Hyper 21 8 port and jumbo maxx shoes.

That explains it.
 
Back
Top