TA05V2 "floating" diffs?

[speedy_w_beans]

I'm starting a TA05V2 build and have found the ball diffs are floating quite a bit between the upper and lower bulkheads. The tension adjusters on each side of the diffs seem to have about 1 mm of vertical play in them, and the ball diffs seem to have about 1.5 mm of horizontal play between the bearings.

I'm thinking about using some thin strips of servo tape to fill in the gap between the tension adjusters and the upper bulkheads, and I'm thinking about investing in a shim company to manufacturer enough shims to center the diffs (of course I'm exaggerating here).

If I start filling the gaps and shimming the diffs, will I be doing something that negates a purposeful design? Do the diffs float this much to let the belts find their natural centers on the pulleys? My DB01s, which are similar to TA05V2 in design philosophy, don't have any of this loose diff movement and the belts are just fine there.

I have no desire to buy a bunch of hop ups to solve a problem; I'd rather make the stock parts work with some creativity. Something seems really wrong about this much free movement, but I want to check in case I'm missing something.

Any other TA05V2 owners out there have thoughts on this?

[volvotech]

I used 53588 (10mm shim set) on my ta05 v1 build. It only had horizontal play in the diffs. I also needed a shim on the center shaft, that had lots of play in it too. I think the ta05 R models included shims in the box.

[ChrisRx718]

I can varify that, I remember building up the diffs on my TA05R and wondering what they were for at first (it was my first 'proper' chassis after a TL01 and TT01).

A quick look at the manual online shows 2 x 0.1mm shims either side of the diff between the outdrives and the bearings.

Do the bulkheads differ from V1 to V2 then?

[speedy_w_beans]

I checked the TA05 and TA05V2 manuals, and both are using the same 51208 "A" parts tree for tension adjusters and bulkheads. I didn't screw the bulkheads together; I just test fitted the parts before committing to assembly and found the vertical movement. I'll check this again; maybe the slack goes away when they're screwed together. Theoretically if you're not seeing any vertical diff movement in a TA05 V1, I shouldn't be seeing it in a TA05V2 either.

The horizontal movement seems very real and it looks like both of you confirmed it. What's interesting is the TA05V2R manual doesn't show any shims for the diffs, but the TA05R manual does. You would think there would be some consistency.

I'll do a little more investigating, but I do plan to ensure the diffs are firmly located in position and not floating around.

[speedy_w_beans]

Well, I looked at these adjusters and bulkheads a second time tonight, and I can definitely confirm the A11 parts are sliding up and down between the A6 and A7/A8 parts in the rear, and the A11 parts are sliding up and down between the N2 and A7/A8 parts in the front. Not cool. I laid some thin strips of servo tape in the A6 and N2 upper bulkheads, and that filled the gap. I left the backing paper on one side of the tape so the parts could be disassembled later without disrupting the tape.

Then I started sliding the ball diffs from side to side and discovered at least one of the A2 parts was coming out of an A11 part partially, which let the outdrive float a bit relative to the bulkhead. I placed an order for some 3RAC-SW10 shim kits to fill in the space between the diffs and outdrive bearings; this should keep the diffs centered and the A2 parts in the A11 parts.

Though these issues are fixable, I'm not too pleased with the quality of this kit so far. The chassis tub is warped just like my TB04 tub is warped. The diff rings aren't keyed to the outdrives, just like the DB01. I'm sure the rubber cement will eventually slip under load and I'll be rebuilding these diffs just like the DB01 diffs. The way the tension adjusters float in the bulkheads and fall apart around the outdrives is not cool; why not supply the necessary spacers to make the front and rear assemblies rock solid? The one good point about this kit so far is the center bulkhead holds the spur and center pulleys in a solid position while letting them spin smoothly.

Grrrr.

[volvotech]

That's pretty bizarre. My ta05v1 went together without any drama outside of the horizontal play in the 3 bulkheads. But I'm with you, the design of the chassis is excellent, but the components don't fit together in the typical tamiya fashion I've been used to.

[speedy_w_beans]

Just a small update to this... I did receive the shim kit the other day and found I needed 0.6 mm on each side of the ball diff to keep it relatively centered between the adjusters. So, with the servo tape in the upper bulkheads and the shims on the outdrives, I finished building the chassis it seems to be working well.