View Full Version : Extra Light Ball Differential Blue

2010.05.21, 08:25 PM
I recently purchased the Extra Light Ball Diff. Needless to say I'm a little upset. I have a reflex bearing set, and the diff shaft is too big to fit. I haven't had a chance to get a set of calipers on it, to measure the diameter.

The stock diff shaft fits. The Stock plastic bushings fit the new diff shaft.

So my question what options do I have? Could I chuck the shaft up to my dremel and polish the heck out of it ? or should I send it back to either atomic or where I baught it.

Any help would be great.


2010.05.21, 10:52 PM
i would try to sand it down by hand. i have a set of atomic f1 knuckles that had the same problem. a little sand paper and all is good.

2010.05.22, 01:54 AM
This is not an uncommon problem. The tolerances between the inner bearing races has always been a little off at times. Some companies will make their bearings 2.02mm for the inner hole instead of 2mm; others will use 2.00mm or even 2.00mm. Also the tolerance on the alloy parts can be off by just ..005 or .01mm and this can make things not fit.
I suggest no dremel. Use ultra-fine grit sandpaoer, 2000-grit is very good. Try and just polish the part of the diff shaft where the bearing sticks very carefully, only a few seconds at a time. You don't want to make the shaft even the tiniest bit smaller than it needs to be to get the bearing seated. If you wrap the paper around the area of the shaft that's too big (don't polish the whole entire shaft unless that is what's necessary), spin the shaft in the paper by hand and keep checking to see every 10-30sec tp see if the bearing fits.:D. Good luck:D

2010.05.22, 07:45 AM
Thanks for the help.

I will get to pollishing. I'm still leaning towards chucking it in the dremel. From running larger scale RC and having to polish enough hinge pins in my life, its a good way to evenly polish round parts.

So to clarify, the part is chucked in the dremel, and spun. DO not and I mean do not attempt to us the dremel with any of its bits / tools to polish anything by hand that needs to be round, you will unevenly finish your part.


2010.05.22, 08:29 AM
If you put your shaft or other parts... in a dremel... do not spin it fast... or you WILL likely bend the shaft.

Remove all the parts from the shaft.

Get a strip of sand paper and fold it over the area you want to sand...

Then just roll the the shaft with that area hanging over the edge of a table...

Action B
2010.05.22, 09:45 AM
Yeah, also if you don't wnat to bend the PN shaft be careful not to breathe on it.

2010.05.24, 05:14 AM
Yeah, also if you don't wnat to bend the PN shaft be careful not to breathe on it.

LOL:D I have a few PN Ultra-Light shafts1.29g, and they seem pretty sturdy. I've heard the PN Light-weight Steel shafts with the center diameter reduced are weak, but are they that bad?

I guess it's a good thing Laxracer is polishing an Atomic Ti shaft in this case:) The new Atomic Ultra-lIght Ti shafts look really nice BTW.

2010.05.24, 05:29 PM
A good hit on the LW steel shaft will bend it -- personal experience. Everyone with that shaft should upgrade to the 7075 alu shaft, it's stiffer, lighter, and all around brilliant. :)

Hopefully Atomic's new Ti-shaft will not be prone to bending, I haven't seen it in person yet.

2010.05.24, 07:54 PM
It's actually easier for us to make the shaft thinner to accommodate different bearing manufacturers. However, this may result in bearing wobble and seriously affect performance. Just use 500 sandpaper to sand it down carefully if a bearing gets stuck. No need to use dremel.

2010.06.27, 06:45 PM
Hello again,

I am wondering if Atomic plans on releasing a "V2" Xtra-Lt. Ball Diff with the ATM 64p spur (Just one spur is fine, such as a 53t)?:D Or are the PN 64p spur gears 100% compatible with the new Atomic Diff?
This new Atomic Xtra-Lt. Ball Diff is a good value overall. As much as I still like 48p (And I know other guys who still dig 48p), a 64p spur would be a nice option. For those of us who want to add SiNi balls to the Atomic Xtra-Lt. Diff, and then add 64p spur... The diff is now $40+. Not a big deal IMHO, but I would just like to know if there is a 64p-Version on the way or if the PN 64p spur are basically-Identical to the new ATM 64p spurs.

Thanks for the info, keep up the great work.:D

2010.06.27, 07:40 PM
PN 64p spurs are compatable. The PN and ATM 64p are very similar designs.

2010.06.28, 04:14 AM
Thanks for he update EMU, I appreciate it. Might save me from buying another set of 64p gears, which I already have boatloads of PN spurs...hehe:)