Teeth and ball bearing carnage

[setecastronomy]

For a long time I had no problem with the XR10 trasnmission so I didn't feel the need to upgrade the stock gears.
Lately I'm driving my heavily modded XR10 more often and longer and I'm suffering some mechanical failures.
Here is what happened to my front axle during a competition last Sunday:





The 5x8 ball bearing is destroyed and both gears lost some teeth.
I know I can upgrade to machined gears which are supposed to be much more robust, but for the moment I replaced them with spare stock ones and put in one of the following oilite bushings.



Last month I destroyed the first gear on rear axle:




I would like to hear your opinion: are these failures the consequence of normal wear ? Do you think the only way to
regain reliability is to upgrade to machined gears and Ace Racing ball bearings ? Where should I check for excessive play ?
Should I drive more respectful of mechanical limits ?

According to what I have read here the 5x8 ball bearings have proven to be very fragile. Maybe the lost teeth on gears is a consequence of the broken ball bearing.
Waiting for advises...

Thanks
Filippo

[Hal]

I, like you, drive with a lot of respect for my rig and I still had the same exact problem. My bearing let go at about 2 months and destroyed all the gears except the locker. It's not you it's the tiny bearings and low quality metal in the stock gears. Definately replace the small bearing inside the top cover with a bushing. Either a Traxxas or Robbob a vendor on here makes a delrin one. Get a large bearing transmission and hardened gears. Hot Racing makes a good setup with larger bearings, as well I think RC4WD. Vanquish products are good but getting very hard to find. I also did a front diff in the rear to get rid of the poorly designed rear plastic housing. Only difficult part was deciding to grind the tang on the rear axle, realy no big deal. These mods have worked out awsome for me so far. I check and re-grease about every month or so with a good quality automotive grease and so far has been bullet proof. A good automotive wheel bearing grease works well, that stuff is very sticky. Good luck with your rig
ps; If you keep rear housing do the 2 BOLT MOD. Search on here to find it, there is a thread explaining it. It keeps housing from seperating and losing gear mesh.

[Robbob]

Yup like Hal mentioned ..... the bearings are too small for the abuse and they probably just reached their life span.

Hot Racing and if you can find them Vanquish made aluminum plates that take bigger bearings (5x10) to handle the stress better. Krazed Builds also makes makes carbon fiber gear plates that take the big bearings.

The outer cover is still good stock, Ive been running the small bearings in mine for 3 seasons. Those bushings will work out there also. RC4WD made delrin cases that took the big bearings but those covers are like unicorns now. Again Vanquish made the aluminum ones for bigger bearings and many guys still have them if you look around.

Hot Racing and Axial still make hardened gears. You can find Hot Racing ones in sets more around ebay. Axial's are sold seperately and Ive always had good luck finding them on RPP.

That upper shaft gear and locker was always our enemy. Youre on the right track with the bushing but you may want to do the 2bolt mod or use the brass inserts from Mcmaster.

The 2bolt mod is all over the XR section if you search it, basically just two long screws coming bottom up and nutted on top. The other is Mcmaster and order a package of these, https://www.mcmaster.com/#94510A030

Youll need to drill the holes the upper mount gos in and press then CA them in place. They help a lot.

With the stock sintered gears I would say throttle back a little when stuck, I never blew any up but they def wouldnt handle what my hardened ones have.

Hope that helps.

[Stormin2u]

I've been using the bushings in mine from out of the box every where they'd fit. But I'm also running the RC4WD hardened lightweight gears in both stock XR10 cases for weight reduction. Bullet proof set up no problems in four years.

[setecastronomy]

Anybody using Acer Racing 5x8 ball bearings ?
If they solve the problem they worth the big money they cost.

Thanks
Filippo

[Hal]

Can't say I know anybody using a "better" bearing. A bushing just works in this application. If it fails it is a little at a time not a catastrophic failure. I change mine out every month or so, or if I do a tear down and they are cheap. You will lose very little from the drag associated with it in place of a bearing on the top shaft. One of the guys at my club only runs bushings and his rig does very well. Krazed Builds has an awsome looking motor/bearing plate, it takes the larger bearings and has the same inserts Robbob mentioned to put in the cases and it's carbon fiber (lighter!) Probably be my next upgrade. Either way bushings or bearings ya gotta do the maintanance, period. Either one will fail with neglect and I like to know how things are holding up in my rig. Hope this gives a little insight and helps your decision on your rebuild. Later