Big Rock Spur Gears keep getting eaten up, need help figuring out why

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thegunsmith

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Arrma RC's
  1. BigRock 4x4
My BRCC eats spur gears every 3-5 batteries and I have no idea why. The motor shaft has no play in it so that shouldn't be the reason. I'm starting to get very annoyed that this is a regular occurrence for me. The only thing I can think of is maybe a rock makes its way into the motor mount area and eats the spur gear up. This truck is very tough in the aspect that I can jump it and tumble it and nothing breaks but it is very weak in that the drivetrain fails almost regularly. I really need help here I am starting to loose motivation to even fix the truck. Also I am wondering about putting a Hot Racing spur in the truck but I heard it creates more problems than it fixes. Anybody here running the HR spur? If so how is it working out for you. Thanks
 
This is not normal. Mine gone through more than 30 packs and I’m still on stock spur.

Are you on the original stock 15t pinion?

When you remove the power module and play with the spur via the opening at the bottom, how much play does it have? It should have some play, but only tiny. Note that the play should be when you rotate, so you should feel the play between the spur and pinion teeth. But it should move in any other way.

Also check the two spur bearing for play.
 
This is not normal. Mine gone through more than 30 packs and I’m still on stock spur.

Are you on the original stock 15t pinion?

When you remove the power module and play with the spur via the opening at the bottom, how much play does it have? It should have some play, but only tiny. Note that the play should be when you rotate, so you should feel the play between the spur and pinion teeth. But it should move in any other way.

Also check the two spur bearing for play.
Yes I am running the stock 15T pinion. just checked for play in the power module through the opening at the bottom and yes it does have just a tiny amount of play when I rotate it. I noticed that the whole slipper assembly has up and down play but I think that is only because the power module isn't installed in the truck. Both of the bearings are fine I recently replaced them with sealed bearings. Thanks
 
I'm running a Hot racing spur in my Granite and it works great. Get a good mesh and no more problems. The clutch is a quarter way out from tight. If you pull out your motor, put a piece of gorilla tape over the hole to cover up the spur then re-install. That'll keep rocks and dirt from getting into your gears! Good luck!:cool:
 
I'm running a Hot racing spur in my Granite and it works great. Get a good mesh and no more problems. The clutch is a quarter way out from tight. If you pull out your motor, put a piece of gorilla tape over the hole to cover up the spur then re-install. That'll keep rocks and dirt from getting into your gears! Good luck!:cool:
Thanks for the tip! So you are saying cover the hole on the bottom of the power module where the spur gear is visible with tape? Correct? Also did you have to add any other upgrades in order to get the HR spur to work? I know its a direct fit but I mean did you have to change the pinion/ diffs at all? I ask because I was told the HR spur will create a lot of heat. Thank you so much!
 
Thanks for the tip! So you are saying cover the hole on the bottom of the power module where the spur gear is visible with tape? Correct? Also did you have to add any other upgrades in order to get the HR spur to work? I know its a direct fit but I mean did you have to change the pinion/ diffs at all? I ask because I was told the HR spur will create a lot of heat. Thank you so much!
No prob! I haven't had issues yet with the HR spur but I've only bashed a few times with it. It just feels more solid. No mods needed to be done. Direct fit. And yes, the opening under the spur is what you want to cover up. (Duperbash trick) The plastic one should be fine if you have a good mesh, run your slipper screw a quarter way out from all the way tight and keep crud out of the gears.?
 
No prob! I haven't had issues yet with the HR spur but I've only bashed a few times with it. It just feels more solid. No mods needed to be done. Direct fit. And yes, the opening under the spur is what you want to cover up. (Duperbash trick) The plastic one should be fine if you have a good mesh, run your slipper screw a quarter way out from all the way tight and keep crud out of the gears.?
Cool I'll give the tape a try and hopefully I won't be having this problem anymore. For the slipper screw I tried running it a quarter turn from full tight but my slipper gets loose after 5-10 minutes of driving. I have to run my slipper almost all the way tight to keep it from coming loose. I tighten all the way and turn the screw maybe 1/10 or 1/8th of a turn out.
 
Up/down play is not normal. Check where bearing slot (the plastic side), it could have warped from heat and so the bearing moves.
I'll post a video in a little while to show what I am talking about, make sure we are talking about the same movement and hopefully determine a fix. Thanks for the help
 
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" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

@Yonic is this normal or is something wrong? The bearing on the plastic side stays seated while the bearing on the side where the center driveshaft connects moves slightly out of its position. Thanks
 
Cool I'll give the tape a try and hopefully I won't be having this problem anymore. For the slipper screw I tried running it a quarter turn from full tight but my slipper gets loose after 5-10 minutes of driving. I have to run my slipper almost all the way tight to keep it from coming loose. I tighten all the way and turn the screw maybe 1/10 or 1/8th of a turn out.
Have you to tried to threadlock it good? They do want to work loose but some threadlock will help!
 
<iframe width="560" height="315" src="
" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

@Yonic is this normal or is something wrong? The bearing on the plastic side stays seated while the bearing on the side where the center driveshaft connects moves slightly out of its position. Thanks

That is normal. All of that play will go away when u install the center driveshaft and it is pushed toward the rear.
 
Have you to tried to threadlock it good? They do want to work loose but some threadlock will help!
I will try to use some threadlock. I was trying not to use any because last time I used some my slipper hub stripped after about 20 minutes of driving so I figured the threadlock was the reason why. I have a few extra hubs at the moment so I will give it a try. Thanks man
 
Is this the truck listed in the for sale section?
yeah it is, thought I had everything fixed but apparently not. I'm hoping the tape under the spur gear will fix it. But if the problem is something other than rocks/dirt getting into the gears I have no idea what the problem could be. I need to update the ad, i'm just waiting on a replacement spur gear and a few other parts.
 
See if your red motor mount is bend or not.. I had that issue before motor mount had a slight bend in it and was making the mesh too tight with the stock predrilled motor mount points, I went and got the hot racing adjustable motor mount and fixed the issue
 
I was thinking about getting the new steel spur gear that comes on the new 4s trucks. Does anyone think I'd have a problem with that? I will check the motor mount today and see if it is bent.
 
I was thinking about getting the new steel spur gear that comes on the new 4s trucks. Does anyone think I'd have a problem with that? I will check the motor mount today and see if it is bent.

The spur gear is not the problem, something else is wrong and you need to fix that. Else you're just trying to mask the problem and you will end up putting strain/break some other part. Like driveshafts. If your slipper is loosening on its own, that's not right, and you are probably setting it too tight and that's why you're breaking spurs. I'd focus on fixing that.
 
The spur gear is not the problem, something else is wrong and you need to fix that. Else you're just trying to mask the problem and you will end up putting strain/break some other part. Like driveshafts. If your slipper is loosening on its own, that's not right, and you are probably setting it too tight and that's why you're breaking spurs. I'd focus on fixing that.
As stated earlier in this thread my slipper doesn't stay tight if I set it any less than a hair from fully tight. So what would you recommend I do since you think the spurs are getting torn up due to the slipper being too tight? Should I just stop driving the car every 5-10 minutes when the slipper comes loose and call it a day? The whole slipper assembly is basically brand new it has like 3-4 batteries through it. Everybody seems to be able to tell me they think I'm wrong but can't tell me why my ARRMA TOUGH vehicle isn't so arrma tough. I literally tore the whole thing apart last night to install the Jimsbearings kit and found nothing. The motor mount isn't bent, I found nothing. Some of you are ARRMA fanboys and I am beginning to hate this brand. Contacted support and they told me to send them my torn up spur gear in order to get a replacement. I told them I would happily send all 7 of my torn up gears if they paid shipping, but of course they wont. Somebody take this POS of my hands
 
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