TT02B Drive cup Chatter

[Ridge 9]

Hi all, I’ve recently converted my dual ridge to brushless and Have now got myself a 3s lipo. I spent a while tonight shimming some of the slop out which appears to have gone quite well.

After doing this I noticed there’s a lot of ‘chatter’ and wobble from the drive cups at the gearbox end. It was easily fixed at the hub with 0.4mm of shims but I’m not too sure what to do at the gearbox end, would Cv’s help? I’m a bit concerned about wear as it has a completely ridiculous amount of power. Was decent with the nimh, looking forward to the first run on the lipo!

[TurnipJF 9192]

Are you running the big stock plastic drive cups with metal shafts, or the smaller all-metal ones? And what is your diff setup?

[Ridge 9]

Thanks for the reply, yes trying to stick with the plastic dog bones and drive cups only as I feel them being the weak link is probably better than other more expensive to fix things down the line being damaged. I have the metal DF02/TT01 diffs etc fitted, modified TT01 61t spur and a 22t pinion at the moment. 
 

Also have frp damper stays, heavier damper oil, gpm steering upgrade, high torque servo saver and probably some other bits I’ve forgotten. The tyres almost balloon off the rims so have some hard foams and glue coming to try and counter that. 

[DeadMeat666 1675]

By "chatter" do you mean that you can hear the dogbones moving inside the cups? Universals may not help here, as they are different only on the hub end, but still normal cup/dogbone on the gearbox end. I believe either yeah racing or 3racing sell universals that are designed to fit in the big plastic cups, if you insist on trying universals but want to keep the plastic cups as "most likely point of failure" as you had mentioned earlier. You'll recognize them by their bigger dogbone ends.

Another thing you could try is to install a TT01 one-way setup, which reduces the stress on the front gearbox altogether, but those would require specific drive cups and either metal dogbones or standard universals to fit on the TT02.

But it all depends on when the chatter/wobble is occuring. Is it during straighline acceleration, while steering full lock and moving forwards, or when you brake/reverse?

[Ridge 9]

So far it’s not been out with the lipo in it, it’s an observation from running it with the wheels off the ground while I was shimming the rest of it. Probably best described as the drive cup at the gearbox end wobbling while it’s spinning, almost like it’s loose. It may be a completely normal thing, it just doesn’t look or sound like it should be. 
 

It may be that I’m worrying about nothing but them running loose like that doesn’t look right, I can’t see it doing the bearing or the housing they slot into much good. 

[DeadMeat666 1675]

Perhaps post a video of what you're describing. I have a TT02B with plastic cups and shafts, so I could compare with mine and give you feedback.

[Ridge 9]

Makes sense and will do thanks, not sure why I didn’t do that in the first place!

I have stumbled across a thread which mentions these DF02 hop up drive cups, wonder if they are the answer.

https://www.ebay.co.uk/itm/392785390782

[DeadMeat666 1675]

8 minutes ago, Ridge said:

Makes sense and will do thanks, not sure why I didn’t do that in the first place!

I have stumbled across a thread which mentions these DF02 hop up drive cups, wonder if they are the answer.

https://www.ebay.co.uk/itm/392785390782

Those will NOT fit on your plastic dogbones as far as I know, putting them in will require that you get metal universals instead.

[TurnipJF 9192]

4 hours ago, Ridge said:

So far it’s not been out with the lipo in it, it’s an observation from running it with the wheels off the ground while I was shimming the rest of it. Probably best described as the drive cup at the gearbox end wobbling while it’s spinning, almost like it’s loose. It may be a completely normal thing, it just doesn’t look or sound like it should be. 
 

It may be that I’m worrying about nothing but them running loose like that doesn’t look right, I can’t see it doing the bearing or the housing they slot into much good. 

 

The issue you refer to is quite normal for a TT-02B running the standard diff outdrives and dogbones. The diff outdrives are not particularly firmly located in the diff gears themselves, and not connected to each other at all, so they do tend to wobble around a bit. It doesn't seem to affect performance though, and while it probably does accelerate wear a bit, we are still typically talking years of running before the parts need replacement.

However since you have already upgraded to DF-02 diffs, you could get a set of splined internal diff gears, the splined outdrives with an alignment pin that passes through the middle of the diff, along with all-metal dogbones and axles to fit them. The splines offer a more precise fit between diff gears and outdrives, and the alignment pin keeps the outdrives concentric with the diff and each other. 

[Jonathon Gillham 4606]

13 hours ago, Ridge said:

So far it’s not been out with the lipo in it, it’s an observation from running it with the wheels off the ground while I was shimming the rest of it. Probably best described as the drive cup at the gearbox end wobbling while it’s spinning, almost like it’s loose. It may be a completely normal thing, it just doesn’t look or sound like it should be. 
 

It may be that I’m worrying about nothing but them running loose like that doesn’t look right, I can’t see it doing the bearing or the housing they slot into much good. 

I think you need to run it on the ground. With wheels in the air every car makes more noise as everything is moving around 

I run mine with stock dogbones and outdrives, and either the DF02 diffs and brushless, or kit motor and diffs (those DF02 diffs suck power, the kit motor is really affected by them) and they are fine. I wouldn't upgrade them as they have lasted years, when they wear out I will buy more the same. Don't throw money at a TT02B...

[Ridge 9]

Probably already thrown too much money at it but I’ve enjoyed improving it. Still regret selling a DB01 Durga far too cheap a couple of years ago as I suspect that would have been better even standard but the TT02B is remarkably strong and is enjoyable to upgrade. My girlfriends 8 year old’s Plasma Edge 2 has a standard drivetrain end electronics, it’s rapid and despite countless launches off the skate park ramps and numerous crashes the only thing that’s broken was the frp front shock tower. His is back to plastic at the front, the frp one is too brittle to be bashed like that. My diffs are also ‘tuned’ with different amounts of anti wear grease so the definitely suck power, work well though. 
 

Videos as promised. 
 

 

[DeadMeat666 1675]

After having viewed the first video a few times, there's nothing particularly abnormal there. The dogbones and cups will naturally wobble more when they're in the air, because the suspension is at full droop and they're at an angle. I imagine the wobble would be a lot less when you actually put it on the ground the dogbones are more level with the diff.

Nothing unusual, carry on  

PS: The buggy must be wicked fast on 3s!

[Ridge 9]

It’s not been run on the lipo yet, it needs a few low power runs before opening it up too. Hoping to take it out tomorrow, the goolrc combo was pretty rapid on nimh so it should be silly! That’s the hope anyway. 

[Ridge 9]

Took it for a run this morning, battery has been cycled three times on the charger so I did give into temptation and gave it a brief squirt of full power. It’s really silly which is great, exactly what I was hoping for. Seems to run straight smooth and quiet, no complaints on the way it handles either.  May try the 23t pinion once I’m happy it’s not getting too hot. Motor was only warm to touch, there is a fan above it though so that will presumably help. 
 

Thanks for the reassurance, it does indeed seem fine once it’s running.