Replacement of 870C and 834B front knuckles: FOUND!!

[jwscab]

I picked up some knuckles/c-hubs/cvd joints on ebay a long while ago, couldn't ever figure out what they were until I happened to find them on tower one day. I know these kinda fit the same way the tamiya parts fit in the c-hub, you need to trim them down, the c-hubs I had were broken, but I think the also fit in the yokomo arms, maybe with a bit of trimming:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTU47&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT75&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT76&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT55&P=K

the only thing I can't recall is if the axle length is right. I was trying to convert the yoke axles to threaded axles for 2.2" wheels. the dogbones would need to be lengthened for a buggy.

[Coelacanth]

Those TA04 front knuckles look almost identical to Kyosho Lazer ZX-5 knuckles...and since we already know regular Optima pot-metal knuckles will fit the Yoke, I suppose these would fit too:

http://www.ebay.co.uk/itm/3Racing-ZX5-17-V2-BU-Aluminum-Blue-Knuckle-Arms-Ver-2-For-Kyosho-Lazer-ZX-5-TF5-/350713106819?pt=UK_ToysGames_RadioControlled_JN&hash=item51a8215183

3Racing P/N: ZX5-17/V2/BU

[Coelacanth]

I picked up some knuckles/c-hubs/cvd joints on ebay a long while ago, couldn't ever figure out what they were until I happened to find them on tower one day. I know these kinda fit the same way the tamiya parts fit in the c-hub, you need to trim them down, the c-hubs I had were broken, but I think the also fit in the yokomo arms, maybe with a bit of trimming:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTU47&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT75&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT76&P=K
http://www3.towerhobbies.com/cgi-bin/wti0001p?&W=001336483&I=LXTT55&P=K

the only thing I can't recall is if the axle length is right. I was trying to convert the yoke axles to threaded axles for 2.2" wheels. the dogbones would need to be lengthened for a buggy.

Yep, you're onto something. These Duratrax knuckles are a direct-fit replacement for Kyosho Optima knuckles, and therefore I'd imagine they'd fit the Yoke too. They're quite a bit more pricey than the 3Racing units, though, but the quality is noticeably better...and I found the 3Racing ones had to have the kingpin standoffs filed down a bit to fit perfectly. I used the 3Racing ones on CYANide and the Duratrax ones--which I managed to find for $19.99 on eBay a long time ago--on Barney, after deanodizing & reanodizing them. As I said, the Duratrax units are a perfect swap-in for the Optima series, no filing required.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVFJ0&P=7

[stickboy007]

Then how about Ta01? Can it be a replacement??

TA01 and TA02 knuckles are exactly the same. In fact, the TA01 and TA02 are almost exactly the same chassis, with the only real difference being the wheelbase - the TA01 was longer. In any case, if you combine the tamiya C-hub and steering knuckles from that generation of chassis, they should fit the YZ10 870c without modification.

[tiger1]

left was the TA04 knuckle with a hex for wheels and top + bottom ball end attached.

right was a GPM 870C knuckle

[stickboy007]

Again, use the Tamiya C-hubs with the Tamiya steering knuckle and you won't need to modify anything. Only difference is that the outer camber link will be mounted a bit higher, which will change the roll center.

[aip47-2008]

Again, use the Tamiya C-hubs with the Tamiya steering knuckle and you won't need to modify anything. Only difference is that the outer camber link will be mounted a bit higher, which will change the roll center.

This Kyosho Part is still readily available and is the replacement part for the OT-16 from Kyosho.

Aaron

[Synergy]

I decided to look into fitting this conversion onto my 870C, I also wanted to replace the carriers with something currenrly available.

It appears that Tamiya TA01/02 hubs and carriers won't work easily, the hubs use a 15mm bearing inboard and a 12mm bearing outboard, both tricky to get down to 5mm id. The inboard bearing are also too far inboard and cause drive shaft binding in the outdrives.

TA04 hubs and carriers look a little easier, I'll be trying those out this week.

[Synergy]

It looks like the TA04 carriers add an additional 5º ish of caster, to overcome this you can of course just file down the TA04 knuckles to fit in the original carriers and this is pretty close to the original geometry, it adds a couple of mm each side to the track width.

However in my case (as I am using one off wheel hubs made by Jake) the spacing of the bearings in the knuckles cause binding between the UJ and wheel hub. So I have a couple of choices, I can either extend the flat on the drive shaft, take a little off the inside of the wheel hub or use a 5x10x3 rather than a 5x10x4 bearing on the inside and or outside of the knuckle. Before I do any of these things I'm going see how the Kyosho SD032 knuckle work out.