Best Truggy Diff Pinion Bearing?

[sikeston34m]

I'm finding the limitations of the bearings in the truggy diffs.

With the spiral cut gears of the 4.3:1 ratio, the pinion not only side loads the bearing, but it also pushes or pulls against the bearings.

I've been using steel ball bearings and they aren't holding up to the increased torque levels of my setup.

I could hear the diff Pop occasionally in the rear under hard acceleration. I took the diff back apart, and found alot of slop in the bearing closest to the pinion. I swapped positions with the two bearings, reshimmed to take all the play out and it worked perfect.

Now about 4 runs later, it's doing it again. On 6S, it will do 60mph+ and top out very quickly. With NO slipper, the setup is able to transfer all the torque that the motor will make. Which is alot!

A needle bearing with thrust bearing type qualities would be ideal, but I can't find any in this size. 8x14x4mm.

Is Ceramic Nitride the toughest out there in a ball bearing? like this one:
http://www3.towerhobbies.com/cgi-bin...?&I=LXPVB1&P=7

[captain harlock]

Ceramic Nitride will please you for sure( ten times the tolerance of steel bearings and 40% lighter). Aside from the fact that they're corrosion resistant, they'll feel even far smoother than the steel type. Acer Racing has a large number of sizes to sellect from. Boca Bearings is also another renowned name in bearings and ceramic bearings.

I'm going to throw in my experience on bearings cause I too have searched the planet for something that can handle a bit of thrust. At a minimum, it'd be nice to not have a grindy bearing each time I take off one of the wheel hubs. Unfortunately, I haven't found the bearing. I tried Acer ceramics. Fried them right up. In fact, they were shot before my steel bearings went out (I specifically mixed steels with ceramics to compare life having similar conditions). They costed me a boatload also. I ended buying mass quantities of steel bearings and just toss em when they get gritty. The friction loss in ceramics is neglible to me considering the $. I do run ceramics in my Neu motor, however (cause the loading is easy on the bearings).

Now my problem may not be entirely the same as yours. I find the root cause of most my failures is dirt working their way in. I have not found thrust to be an issue in the front/rear diffs. It sounds to me like you had a bad shim job which will toast any bearing. Once they are sloppy, you cannot shim again to compensate. Your bearing will be out of concentricity with the race. Are you certain with new bearings and a good shim job the problem keeps happening? The spiral cut gears require very close tolerances, more than one would think.

[sikeston34m]

Originally Posted by cadima

I'm going to throw in my experience on bearings cause I too have searched the planet for something that can handle a bit of thrust. At a minimum, it'd be nice to not have a grindy bearing each time I take off one of the wheel hubs. Unfortunately, I haven't found the bearing. I tried Acer ceramics. Fried them right up. In fact, they were shot before my steel bearings went out (I specifically mixed steels with ceramics to compare life having similar conditions). They costed me a boatload also. I ended buying mass quantities of steel bearings and just toss em when they get gritty. The friction loss in ceramics is neglible to me considering the $. I do run ceramics in my Neu motor, however (cause the loading is easy on the bearings).

Now my problem may not be entirely the same as yours. I find the root cause of most my failures is dirt working their way in. I have not found thrust to be an issue in the front/rear diffs. It sounds to me like you had a bad shim job which will toast any bearing. Once they are sloppy, you cannot shim again to compensate. Your bearing will be out of concentricity with the race. Are you certain with new bearings and a good shim job the problem keeps happening? The spiral cut gears require very close tolerances, more than one would think.

I'm pretty sure I know when most of the damage happened. I jumped and held the throttle until it landed. It wasn't a big jump, but I think it was enough. Dirt was not the issue.

When I opened it up and checked the inboard bearing, I could feel where the balls dented the race. If that makes sense. I'm sure this took the ball bearings out of round also. It went downhill from there.

My Ceramic Nitride bearings just came in. I haven't gotten them installed yet. I ordered the good ones, the ones manufactured to tight tolerances. From everything I've read, Ceramic Nitride ball bearings are MUCH harder than conventional ball bearings. However, there isn't any indication of harder bearing races being using with them. So, I won't know how they hold up until I try them.

I'm hoping I just got a bad set of regular bearings. This is my first time replacing them. I feel like my shim job was good. I did my research and went with the recommendation the first time.

I got my new motor wound tonight. Soon I will put the new bearings in along with installing the new motor. We'll see how it works out.

funny you should mention the race not being harder. I inspected the ceramic bearings I fried (flushed them and viewed with scope) and it was the cage and race that seemed to be fried. The balls looked good.

[captain harlock]

If only we could use full ceramics in our vehicles....even so, they'll cost us four times the cost of the ceramic nitride ones.