TT02B axles falling out

[bozdee 14]

Hi Team,

I’m building a couple of TT02Bs for a bit of fun with me and the kids. I’m currently having an issue with the axles. For reference I’m using GPM shocks, YR gearbox joints, universals, knuckles and the Tamiya turnbuckle kit. I’ve tried eliminating the issue by going back to the standard dogbones, knuckles and suspension positions all with not much luck. My issue thus far has mainly been with the rear but there is also a lot of play in the front too.

Basically, I can’t stop the dogbone/universal from popping out. Any ideas on how I can correct this issue and ideally keep the aftermarket bits?

[bozdee 14]

Best thing I can think of this far is to chuck an extra bearing here to push the universals further into the knuckle and stop the movement.

[TurnipJF 9192]

How about shortening the upper link turnbuckles to run more camber, closing the distance between axles and outdrives?

[bozdee 14]

They are already shorter than the standard upper arms. So the wheels are already tipping in a fair bit.

The bearing trick seems to be the best workaround I can think of at the minute.

[DaveBuildsRC 210]

Shocks too long?

[DeadMeat666 1675]

I have the exact same setup, except for one difference: I'm using the standard TT02B 'chunky' diff outdrives, and CVDs that have bigger ends on the diff side to properly fit into those outdrive cups. That works a treat, and I've never had anything pop out, despite having monster wheels on my TT02B and driving on rough terrian, in anger, quite often.

This is the best pic I have at hand; hopefully you can see the (proper) mating between the diff cup and the CVD:

[bozdee 14]

2 hours ago, DaveBuildsRC said:

Shocks too long?

Same as stock. Ran in the higher position to get more clearance but moved to standard position and still had issues.

2 hours ago, DeadMeat666 said:

I have the exact same setup, except for one difference: I'm using the standard TT02B 'chunky' diff outdrives, and CVDs that have bigger ends on the diff side to properly fit into those outdrive cups. That works a treat, and I've never had anything pop out, despite having monster wheels on my TT02B and driving on rough terrian, in anger, quite often.

This is the best pic I have at hand; hopefully you can see the (proper) mating between the diff cup and the CVD:

Where did you get the universals with the bigger side the suit the chunky outdrives?

Love how you secured the steering arms! I went the other way and slid the m3 nut into the aperture on the underside of the tub!

[DeadMeat666 1675]

10 minutes ago, bozdee said:

Where did you get the universals with the bigger side the suit the chunky outdrives?

Love how you secured the steering arms! I went the other way and slid the m3 nut into the aperture on the underside of the tub!

I got these: https://www.gpmparts.com/tamiya-tt02b-steel45-frontrear-cvd-swing-shaft-64mm-1pr-set-for-dt03-gpm-stt2b264c-p-90068334.html but I'm not sure where you can find them in stock these days. They shouldn't be too hard to find.

Edit: there you go https://www.ebay.com/itm/GPM-DT3264SC-Steel-CVD-Universal-Swing-Shaft-Set-For-Tamiya-DT02-DT03-TT02B/131885304490?epid=1378709583&hash=item1eb4fa0aaa:g:U~kAAOSwPhdU1IG9

(no affiliation, just helping out)

I intended to secure the steering arms like you did, but the spare screws I had on hand were a little long, so I just turned them around lol. Sort of a bodge, but it works just as well.

[Matty36 267]

I would try moving the top shocks in as far as possible and the lower shock as far out as possible to limit the amount of travel. For a better fix I would put a spacer in the shock to limit the travel. Are they definitely buggy driveshafts, not touring car ones, on full compression they should nearly touch the inside of the outdrive, if not then they are too short.

[bozdee 14]

17 minutes ago, DeadMeat666 said:

I got these: https://www.gpmparts.com/tamiya-tt02b-steel45-frontrear-cvd-swing-shaft-64mm-1pr-set-for-dt03-gpm-stt2b264c-p-90068334.html but I'm not sure where you can find them in stock these days. They shouldn't be too hard to find.

Edit: there you go https://www.ebay.com/itm/GPM-DT3264SC-Steel-CVD-Universal-Swing-Shaft-Set-For-Tamiya-DT02-DT03-TT02B/131885304490?epid=1378709583&hash=item1eb4fa0aaa:g:U~kAAOSwPhdU1IG9

(no affiliation, just helping out)

I intended to secure the steering arms like you did, but the spare screws I had on hand were a little long, so I just turned them around lol. Sort of a bodge, but it works just as well.

Almost bought these today if it weren’t for my bearing trick. I actually was going to bin all of the YR bits in favour of the GPM ones.

So the GPM universals fit the chunky diff cups in lieu of the small ones? Very hard to tell from the eBay listing and not much info on their website. Tamiya also have their own diff cups and universals that I looked at.

I ended up going to the local hardware to get screws the right size. I think 18mm was the correct size.

[bozdee 14]

11 minutes ago, Matty36 said:

I would try moving the top shocks in as far as possible and the lower shock as far out as possible to limit the amount of travel. For a better fix I would put a spacer in the shock to limit the travel.

Good suggestion but nothing seems to work shocks wise, there is just too much play but the more the shocks compress, the more the problem resolves.

[DeadMeat666 1675]

59 minutes ago, bozdee said:

Almost bought these today if it weren’t for my bearing trick.

My concern is that your bearing trick means that the diff cups are not completely mating with the diff gears anymore and you'll have a driveline failure soon.

[TurnipJF 9192]

I remember having issues with my TT-02B drivetrain upgrades too, stemming from the fact that many parts are sold as fitting both the TT-02B and DF-02, whereas the axle cups and diff outdrives look very similar but are not exactly the same dimensions on the two chassis. In my case though, I was having the opposite issue - binding due to not enough clearance after fitting GPM alloy dogbones that supposedly fit both chassis. I ended up replacing the axles and diff outdrives with DF-02 items, resolving the issue.

I wonder if some incompatible combination of DF-02 and TT-02B parts might be behind your difficulties, and if trying a different combo, or switching to all-DF-02 or all-TT-02B parts might resolve it?

[Matty36 267]

Does it still have the issue with the original shocks fitted.

[Problemchild 2149]

You sure those are the correct dog bones?

if the lower arm is the correct length it can only be the drive shafts or the drive cups 

I use yeah racing ones and I don’t have the issue you are seeing 

im sure my metal drive shafts look different 

JJ

[Problemchild 2149]

So my front drive shafts are 76mm

 

(note the collar halfway along the length)

the stand off between the top arm fixing point and the hub rotating point is 12mm

And the axle stub protruding from the YR hub is 16mm

 

are you sure you have a bearing in on the inside of the hubs??

JJ

[bozdee 14]

13 hours ago, DeadMeat666 said:

My concern is that your bearing trick means that the diff cups are not completely mating with the diff gears anymore and you'll have a driveline failure soon.

Going to take a risk on this one.

9 hours ago, Matty36 said:

Does it still have the issue with the original shocks fitted.

will test that out tonight, I mean the aftermarket shocks are the same size so you’d think it wouldn’t matter but let’s see.

5 hours ago, Problemchild said:

You sure those are the correct dog bones?

if the lower arm is the correct length it can only be the drive shafts or the drive cups 

I use yeah racing ones and I don’t have the issue you are seeing 

im sure my metal drive shafts look different 

JJ

I only have the standard plastic dogbones, drive cups and diff cups (the chunky ones). They don’t work and 100% they are the correct ones as they came with the kit.

Aftermarket stuff as follows:

YR diff cups for TT02 - https://www.yeahracing.com/steel-front-rear-gear-joint-for-tamiya-tt02-tt02-017-00036592?search=Tt02&description=true

YR universals for DF03 and TT02B - https://www.yeahracing.com/g45-universal-steel-swing-shaft-for-tamiya-df03-tt02b-df03-015v2-00026617?search=Tt02b&description=true

4 hours ago, Problemchild said:

So my front drive shafts are 76mm

 

(note the collar halfway along the length)

the stand off between the top arm fixing point and the hub rotating point is 12mm

And the axle stub protruding from the YR hub is 16mm

 

are you sure you have a bearing in on the inside of the hubs??

JJ

Will check all measurements tonight but yes, I do have bearings inside the hub.

[B.RAD 240]

23 hours ago, DeadMeat666 said:

I have the exact same setup, except for one difference: I'm using the standard TT02B 'chunky' diff outdrives, and CVDs that have bigger ends on the diff side to properly fit into those outdrive cups. That works a treat, and I've never had anything pop out, despite having monster wheels on my TT02B and driving on rough terrian, in anger, quite often.

This is the best pic I have at hand; hopefully you can see the (proper) mating between the diff cup and the CVD:

Do you have a pic of this on the monster wheels please? I'm toying with getting the Neo Scorcher and if it can run big wheels that might make my mind up for me!

[DeadMeat666 1675]

2 hours ago, B.RAD said:

Do you have a pic of this on the monster wheels please? I'm toying with getting the Neo Scorcher and if it can run big wheels that might make my mind up for me!

[bozdee 14]

Ok so I looked at this kids car and they don’t seem to have the same problem on the front. The only differences between the two being they have GPM turnbuckles in lieu of Tamiya and they have the kit lower arms whereas I have the Hop-up Tamiya ones (GRP). I don’t think I’ll be able to (or need to) fit a bearing in the front.

The problem still seems to be there on the rear.

 

[B.RAD 240]

2 hours ago, DeadMeat666 said:

Sorry for the thread hijack, I'll stop now, but that does look epic!!!

[DeadMeat666 1675]

Yes my apologies as well @bozdee. 

I do hope my earlier feedback was useful nonetheless.

[Problemchild 2149]

Something is incorrect 

at full extension of my springs (puts the rear end 40mm off the ground) the dog bones sit fully in the wheel cups and 50% in the gearbox cups!!

JJ

[Problemchild 2149]

Measure the dog bones 

JJ

[bozdee 14]

On 2/23/2021 at 5:07 AM, Problemchild said:

Measure the dog bones 

JJ

They are all the same! I can’t work out where the difference is! This is driving me crazy!