LRM Differential Bearings

[knixdad]

Has anyone ever gotten the measurements of the bearings used in the A-3020 differential gear? I've searched around a bit and other than buying a complete A-3020 in the package, I can't seem to find where I can get replacement bearings.

The original single bearing is a 1/4 X 3/8 X 1/8. The A-3020 has 2 thinner bearings that together are just a little less than 1/4 inch. Doubling up the 1/8 inch bearings doesn't leave enough room to tighten the differential properly.

[LosiXXkid]

Has anyone ever gotten the measurements of the bearings used in the A-3020 differential gear? I've searched around a bit and other than buying a complete A-3020 in the package, I can't seem to find where I can get replacement bearings.

The original single bearing is a 1/4 X 3/8 X 1/8. The A-3020 has 2 thinner bearings that together are just a little less than 1/4 inch. Doubling up the 1/8 inch bearings doesn't leave enough room to tighten the differential properly.

I looked for them over the course of a few days but without success - all the ones currently available are 1/8" thick which is no good as the diff binds up rendering it useless. However, in the absence of the slim bearings required for the moulded plastic diff halves you could always buy the Thorp JRX-2 diff halves just like these...

http://www.ebay.co.uk/itm/Team-Losi-JR2-JRXT-JRT-PRO-Aluminum-Diff-Gear-Set-By-Thorp-Dirt-Burners-/360632348031?pt=Radio_Control_Parts_Accessories&hash=item53f75ced7f

...which allow the use of the standard 1/8" thick bearings (that are readily available) due to the deeper recess in the female diff half when compared to the stock Losi part.

Apologies if you already know this.

[jwscab]

it is a special thin bearing. I suppose if you could get your hands on a brass or plastic bushing, you could grind it down to fit with a standard bearing next to it to get it all line up properly so at least it's partially bearing and partial bushing.

[knixdad]

That does simplify things, totally forgot about that Thorp set. I have a LRM with the dual bearing gear in it but whomever assembled it years ago used a single 1/8 inch bearing. So it was kind of floating there. I don't think it was run like this, it would have been torn up pretty bad.

Pulled open a spare LRM but of course it was a single bearing differential.

[knixdad]

it is a special thin bearing. I suppose if you could get your hands on a brass or plastic bushing, you could grind it down to fit with a standard bearing next to it to get it all line up properly so at least it's partially bearing and partial bushing.

I found a quick and dirty fix using your idea. Take one of the flanged 1/4 X 3/8 bushings from the RC10 Classic kit, attach sandpaper to a flat surface, then work it flange side down until the flange is gone. Perfect bushing size to take fill in the gap left if you use a single 1/8 inch thick bearing.

I'll be getting the Thorps anyway

[highwayracer]

When I built my first bb diff, I didn't realize there was a difference...so I used 1 standard and 1 thin bearing. First impression....really smooth. Second impression, why is the diff gear turning without any friction

On solution would be to remove some the material from one of the diff halves. This gives extra room for the bearings...enough where the diff balls can get some contact. One thing to consider...if you resurface your diff rings, it will eventually begin to slip again.

Regards,
Roger