Kraton Kraton: Dogbone keeps jumping out of input shaft cup

[RC-Dude]

The front dogbone keeps jumping out of the Kraton input shaft cup when jumping.
I drive a 6s Kraton V4 and my buddy a V5. Same problem.
Take out the spacers?
What do I do?

 

[jondilly1974]

Yep take out the spacers and trim the length of the arms if needed.

 

[RC-Dude]

Thanks!

 

[Kingleo619]

https://www.ebay.com/itm/Hot-Racing...2349624.m46890.l49286&mkrid=711-127632-2357-0

https://www.ebay.com/itm/Hot-Racing...2349624.m46890.l49286&mkrid=711-127632-2357-0

I run these for a typhon and never had pivot ball pop out in 2 yrs but I have snapped a dog bone once when ball should of popped out put didn't

Like @jondilly1974 said take them spacer out

 

[Jluther@becoinc]

The front dogbone keeps jumping out of the Kraton input shaft cup when jumping.
I drive a 6s Kraton V4 and my buddy a V5. Same problem.
Take out the spacers?
What do I do?

On the V5 you can take a body reamer and make the hole in the aluminum cap just big enough for the flange on your pivot ball to go through. After that you can shorten
Your arm up by wallowing the plastic out to let that flange go back a couple mm. I did this on all my Arrmas. No more axle issues.

 

[KevinC]

Setting your droop properly will help mitigate this.

cheers,
kev

 

[eXpi]

I removed the stock arms and changed to rpm arms, never had any problems after that.

 

[RC-Dude]

How do I shorten the wishbones on the Talion? So that the dogbones don't jump out.
The aluminium suspension arm end cap #330645 gets in the way.
I shortend the upper wishbone about 2mm but the camber is too big.
Any ideas?

 

[KevinC]

I’d try putting bump stops on your shock shafts first before you mess with the A-arms.

cheers,
kev

 

[Lukas412]

Setting your droop properly will help mitigate this.

cheers,
kev

I see this solution a lot. In my case the dog bone always pops out on max compression. How does droop fix this?

 

[jondilly1974]

I see this solution a lot. In my case the dog bone always pops out on max compression. How does droop fix this?

He changed his post to say bump stop which is correct.

 

[KevinC]

Well, I did mean droop……but this won’t help upon compression…..only during times when the arms are fully unloaded. Dog bones pop out during these times too if droop is set low enough to allow your shock to fully extend.

On the opposite end of the spectrum (high compression), if you can stop your shock from fully compressing, the dogbone has less of a chance of popping out. This is where the bump stop helps, as well not letting the bottom of the shock body smash into the shock rod end/spring perch.

A combo of both droop/bump…….in my experience has stopped this. I had it happen on the Mojave quite a bit until I made the proper changes.

cheers,
kev

 

[RC-Dude]

Or longer dogbones. Has anyone got a recommendation?
Is there any bump stop part number?

The dogbones come out during the long jump landings. Not sure if the bump stops put too much load on the shocks.

 

[KevinC]

Longer dogbones run the risk of bending under compression and I’m pretty sure no one is making them. There’s companies that make bump stops…….or you can just use 3-5 mm diameter fuel line from a local hobby shop. I cut mine to about 8mm long and slid it on the shock shafts so it sits right above the shock rod.

Heres an example of manufactured bump stops….

 

[B2Humla]

I used four M4 1mm nylon washers on each shock rod. So 4mm in total. This limits max shock compression.
Also screwd the pivot balls in as much as I could, and still wheel camber is ok. Droop screws also set.
This looks to fix the issue on my Kraton 1/8 EXB.
Did some serious long jumping this sunday, and no issues or broken on the car.

I use stock Arrma arms.
But I have some RPM lower front arms and when compared with the Arrma it looks like the RPM arms are 2-3mm shorter.
Some Youtubers say that using the RPM lower arms fix this issue, so if they really are 2-3mm shorter that is maybe why.
But I just did a quick comparison, so I could be wrong here.

Of course you can remove the spacers on the Arrma arms also, I did not test that fix.

A note here: Just got a new Arrma Kraton 1/8 EXB. And that car did not have any plastic spacers inside the upper pivot ball.
Just a thin metal washer. My first Kraton 1/8 EXB had two plastic washers I believe. So Arrma looks to have made some updates to the EXB here.
The metal washer is thinner than the two plastic washers, so looks like Arrma have tried to fix this issue on newer EXB's... maybe.

 

[RC-Dude]

Thought about using O-Rings but the Nylon washers seem to make more sense. What is the outer diameter? 8mm?

 

[B2Humla]

Yes 8mm.

Here is how my new Kraton 1/8 EXB came. Got it today. Note the thin metal washer. On my "old" EXB there was 2 plastic washers, some thicker.
But... don't believe this alone would fix the issue... not that much different from the old car with two plastic washers.

 

[RC-Dude]

Same on my Talion EXB.

 

[Moirae]

I used four M4 1mm nylon washers on each shock rod. So 4mm in total. This limits max shock compression.
Also screwd the pivot balls in as much as I could, and still wheel camber is ok. Droop screws also set.
This looks to fix the issue on my Kraton 1/8 EXB.
Did some serious long jumping this sunday, and no issues or broken on the car.

I use stock Arrma arms.
But I have some RPM lower front arms and when compared with the Arrma it looks like the RPM arms are 2-3mm shorter.
Some Youtubers say that using the RPM lower arms fix this issue, so if they really are 2-3mm shorter that is maybe why.
But I just did a quick comparison, so I could be wrong here.

Of course you can remove the spacers on the Arrma arms also, I did not test that fix.

A note here: Just got a new Arrma Kraton 1/8 EXB. And that car did not have any plastic spacers inside the upper pivot ball.
Just a thin metal washer. My first Kraton 1/8 EXB had two plastic washers I believe. So Arrma looks to have made some updates to the EXB here.
The metal washer is thinner than the two plastic washers, so looks like Arrma have tried to fix this issue on newer EXB's... maybe.

The Nylon washer idea was great! I just bought an assorted set from amazon for like 6$ and added 5 of them to my front talion shocks as I was also having this problem. Was also going to add it to my kraton too but I recently changed the springs to be much stiffer which I think already helps to stop this. I'll probably do it anyway just to be safe lol.

Great idea!!

 

[uncontrolledpair]

Is there still enough suspension travel for the chassis to slap with the bump stops?