Granite Granite chewing spur gears

[Jsky87]

A few months ago I got a used granite mega that the guy put a vxl system in. I bought the blx slipper and motor mount. Swapped the pinion/spur to 32p. (The pinion is 32p the spur is .08 mod, but I don't think that's the problem). I ended up putting a $30 motor off eBay that looks like a hw but isn't. 3670sl/3200 kv. And I just got a hobbywing max10sct esc. Anyway the whole time I've owned this thing it eats spur gears every pack or so. 2 in 5 minutes one time. I've put almost 10 in the entire time I've owned this thing. I've bought tires, tx/Rx, batteries, charger. I have alot of $ into this thing and it's getting frustrating. The bearings seem fine, the mount isn't bent. I hold a wrench into the slipper and push it forward until it stops to set it so I think that's okay. The bearing on the slipper bolt is good. I seen diffs were only $17 on Jenny's so I replaced those, and the input gear in the rear seemed super tight, almost pushing against the housing. But I read on here that it was normal. Anyone think it could be that ? The only thing mechanically that makes sense to me is the yokes or input gear. I have a slash too and I have been setting mesh for a few months and only have a problem with this truck. I run a piece of paper through it without ripping it. Barely leaving an indentation. Any advice is appreciated. Tia

 

[parcou]

A few months ago I got a used granite mega that the guy put a vxl system in. I bought the blx slipper and motor mount. Swapped the pinion/spur to 32p. (The pinion is 32p the spur is .08 mod, but I don't think that's the problem). I ended up putting a $30 motor off eBay that looks like a hw but isn't. 3670sl/3200 kv. And I just got a hobbywing max10sct esc. Anyway the whole time I've owned this thing it eats spur gears every pack or so. 2 in 5 minutes one time. I've put almost 10 in the entire time I've owned this thing. I've bought tires, tx/Rx, batteries, charger. I have alot of $ into this thing and it's getting frustrating. The bearings seem fine, the mount isn't bent. I hold a wrench into the slipper and push it forward until it stops to set it so I think that's okay. The bearing on the slipper bolt is good. I seen diffs were only $17 on Jenny's so I replaced those, and the input gear in the rear seemed super tight, almost pushing against the housing. But I read on here that it was normal. Anyone think it could be that ? The only thing mechanically that makes sense to me is the yokes or input gear. I have a slash too and I have been setting mesh for a few months and only have a problem with this truck. I run a piece of paper through it without ripping it. Barely leaving an indentation. Any advice is appreciated. Tia

Hi and Welcome!

I do not have your model rig. My issue was a little opposite on a different 3S rig...eating the input gear to the spur. Heavy belted tires were my issue. Someone will chime in on your issue.

 

[RCbuzz]

Would you mind posting a picture of your power module setup (inside) and one of your chewed up spur?

Do you run in gravel or sand? Have you taken a look at sealing your power module?

From looking at your post it looks like you have ruled out the big causes... This it abnormal though, after sealing my power module I checked it after about 15 packs and the spur looked great..

When the power module is fully re-assembled but not put back in the truck, try turning the spur left and right (just a tiny bit and not turning the motor) to feel your mesh, you should hear the slight click sound of your spur hitting your pinion (the paper width you set). It should be very minimal. If you feel a lot of play you mesh may be too loose.

 

[Moonstonemike]

If your motor mount plate is bent even a bit the spurs will get chewed up. Sorry just saw you said mount was good. Look for any binding in the drive train. If the diffs seemed tight it could definitely cause that problem.

 

[Jsky87]

Would you mind posting a picture of your power module setup (inside) and one of your chewed up spur?

Do you run in gravel or sand? Have you taken a look at sealing your power module?

From looking at your post it looks like you have ruled out the big causes... This it abnormal though, after sealing my power module I checked it after about 15 packs and the spur looked great..

When the power module is fully re-assembled but not put back in the truck, try turning the spur left and right (just a tiny bit and not turning the motor) to feel your mesh, you should hear the slight click sound of your spur hitting your pinion (the paper width you set). It should be very minimal. If you feel a lot of play you mesh may be too loose.

I don't have a new spur gear yet. But all of them have stripped this same way, even with the pinion lined up. Someone told me it looks like the copper bushing in the motor is bad, causing it to pull in too much under power. The motor has less than 10 packs through it though.

 

[Allen Wrench]

Is that a ball bearing out of one of the bearings on the slipper, if the bearing is gone the mesh will change, I had one of the original bearings go bad very quickly…

 

[Jerry-rigged]

I'd bet it is bad mesh. Almost the entire tooth is gone, so Maybe a bit tight (too loose mesh will leave most of the tooth, just knock off the top half). Tight mesh will cause the teeth to wear quick then shred...

The 4x4 motor module makes setting the mesh tough. When you set the motor position, the spur is only held by one bearing, so it can move around. If you use some variation of the "Use paper and jam then together" method, the spur will move, and the mesh will be off. You must set it by feel, dry fit the power module together, then rock the spur to test mesh, again, by feel. You want a tiny bit of movement / lash between the spur and pinion, but not too much. If there is no lash, it is too tight, and the spur will strip.

 

[Hector_Fisher]

I'd bet it is bad mesh. Almost the entire tooth is gone, so Maybe a bit tight (too loose mesh will leave most of the tooth, just knock off the top half). Tight mesh will cause the teeth to wear quick then shred...

The 4x4 motor module makes setting the mesh tough. When you set the motor position, the spur is only held by one bearing, so it can move around. If you use some variation of the "Use paper and jam then together" method, the spur will move, and the mesh will be off. You must set it by feel, dry fit the power module together, then rock the spur to test mesh, again, by feel. You want a tiny bit of movement / lash between the spur and pinion, but not too much. If there is no lash, it is too tight, and the spur will strip.

^^^ This!

I went through alot of spurs before i figured this out. Setting the mesh on the 3s trucks is a trial and error process and definitely a work of art. I second the "dry fit" process. Snap the case together any time you need to check for the right gear mesh.

 

[Jsky87]

Is that a ball bearing out of one of the bearings on the slipper, if the bearing is gone the mesh will change, I had one of the original bearings go bad very quickly…

I didn't see that until you pointed it out lol. It's a piece of solder I ended up switching to a steel spur and haven't had a problem since.

^^^ This!

I went through alot of spurs before i figured this out. Setting the mesh on the 3s trucks is a trial and error process and definitely a work of art. I second the "dry fit" process. Snap the case together any time you need to check for the right gear mesh.

Honestly I think I was doing it wrong. I got a steel spur and used this method to set the mesh very.carefully. I've run over 10 packs and so far so good.

^^^ This!

I went through alot of spurs before i figured this out. Setting the mesh on the 3s trucks is a trial and error process and definitely a work of art. I second the "dry fit" process. Snap the case together any time you need to check for the right gear mesh.

Honestly I think I was doing it wrong. I got a steel spur and used this method to set the mesh very.carefully. I've run over 10 packs and so far so good.