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Looking for details and options for the Triumph ball diff rebuild.

The Acer ceramic balls look like a cheap and better alternative to the Kyosho LA-4 and WBD-6 balls.

I believe the diff balls are 3/32, correct?

Does anyone have the size for the thrust balls?

Also, are there any alternatives to the WBD-4 diff plates and WBD-2 thrust washer plates?

The Triumph diff is like an evolution of the old Ultima ball diff. I believe it uses 3mm diff balls. I don't remember what size the thrust bearing balls are. WBD-1 contains the diff plates though I think there are multiple versions of this parts bag with different contents. WBD-2 is used in all Kyosho diffs of that era.

Ive just done my zxr diffs. Ive bought 3mm ceramic balls from jEModels and 1/16inch thrust balls from much more. Feels smooth. I use acer bearings for the layshaft and wheels. I use if in the uk nuclear rc diff and thrust grease.

This seemed like an appropriate place to post this...I just replaced the steel balls in my Turbo Optima Mid SE's diff with 3mm ceramic balls. At a glance, it seemed the original steel balls were a bit bigger, and my caliper confirmed this. The steel balls kind of popped into place in the square holes in the diff gear, whereas the ceramic ones could push smoothly right through. The difference in diameter was approximately only about .2 to .3 millimeters. The stock steel balls were about 3.2-ish mm. But what they hey, I tried installing the new ceramic balls, reassembled the diff, and it otherwise seems to feel nice and smooth.

I'm still not too clear on how much to tighten the ball diff, but it seems to feel alright.

I wanted to install an older Optima-style gear diff for the no-maintenance benefits, but the Optima gear is a good .4 mm smaller than the Optima Mid's gear and I couldn't see any way to swap the Mid-style diff gear with the Optima-style gear.

Does Kyosho part WBD-5 (ball diff shaft set) contain the needed parts to rebuild the diff? I haven't been able to find a good description of the parts bag and can't find a picture that clearly shows the contents. I'm curious if it contains the diff plates along with the diff and thrust balls.

diff balls that measure 3.2mm (or so) are 1/8" diff balls, just in case you didn't have a conversion calculator in front of you.

jkelm24 wrote:Does Kyosho part WBD-5 (ball diff shaft set) contain the needed parts to rebuild the diff? I haven't been able to find a good description of the parts bag and can't find a picture that clearly shows the contents. I'm curious if it contains the diff plates along with the diff and thrust balls.

Can't remember if it's that particular bag, but be aware the diff plates were updated at one point without changing the part number. Unfortrunately, that's one of the few cases where the updated parts are not compatible with the old parts...