Kraton I’m over my exb, won’t last a full pack.

Rainger40

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Had this thing around a month now and only gotten one full pack out of it. It was pathetic the first run so I put 17t pinion and 500k in center diff. Livened things up nicely for all 5 mins of testing until the diff outdrive broke. Not on a 100’ jump at 50mph, but bounce over my driveway. Rear end came up, I hit throttle to bring it down and it breaks. Mind you this is slow speed and less than a foot off ground in rear. So I order and wait for parts, fix it up and take it out again today. All is going great, big jumps, wheelies, the works. Then like before a slow speed blip over a bump on a side of a jump I’m going to line up and hit, rear goes up, I throttle it down and same drive cup shattered again. So it’s breaking with rear up in air and front down on ground on throttle if that makes sense. I don’t know what to think. Droop is set, driveshafts aren’t hitting the cups at full droop or compression, there was no binding, I just don’t get it. My patience for “extreme bash” is about gone. Any suggestions here guys, this truck just isn’t fun anymore.

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Yas

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I reckon the driveshaft is putting pressure on the outdrive. Is the driveshaft pin center? Is there any lateral play for the driveshaft, from outdrive to axle?
 

dk3000

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So the front left outdrive is broke? I'm asking because after reading your rant which I get because things do happen at the oddest moments but can you show a photo of the actual damage cup. Seems like all that happened was your front dog bone came out and spun. I just had the same issue but only had it come out one time since owning.
 

RC-Dad

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from your photos it looks like your front dogbone popped out of the diff cup. Can happen if front end goes into full compression, similar to what you described by throttling out of tail up. Check the pillow balls and make sure they are tight, if they have come loose it will allow that dogbone to release and damage the a arm like you see in your picture.
 

Rainger40

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It’s broke, not just out. If it just came out I’d have put it back and finished the battery haha. Pillow balls were adjusted, stock k6s (spektrum firma) electronics w/factory settings. Here’s a pic of the first broke cup and new one. Sorry I was pissed earlier and didn’t realize I took/uploaded pics that looked like potato vision. For the record I didn’t rush anything on this build. First 6s, was super pumped so I took my time and made sure(I think) that everything was installed, filled, adjusted ect properly so I could avoid unnecessary breakage and down time like this. Of course it can’t break on the quick side of the diff to change either right.

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D3MON

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i was looking into maybe getting the v5/EXB front arms for my kraton, and i saw a few people were having issues with the front arms being too flexible allowing the driveshafts to pop out somewhat easily. wondering if that is what was happening with yours, but wasnt all the way out and giving it power torqued the tabs weird and snapped them
if i remember correctly, the fix was to either get RPM front arms, or the stock v4 arms up front.
 

Wildvoodoomagic

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Im pretty sure this is from you hitting the throttle to bring the rear down. Might be using too much throttle or landing with some throttle especially with the front end down it will receive all the landing force from your truck (which will increase the torque needed to rotate the front wheels putting strain on the driveshafts and outputs) and the torque from the motor is all going to the front diff and drive cups.
 
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Im pretty sure this is from you hitting the throttle to bring the rear down. Might be using too much throttle or landing with some throttle especially with the front end down it will receive all the landing force from your truck (which will increase the torque needed to rotate the front wheels putting strain on the driveshafts and outputs) and the torque from the motor is all going to the front diff and drive cups.
I agree. I honestly think this is repeated driver error. EXB was driven -> somethinghappened to break it -> EXB was driven again, repeating the same thing -> EXB broke in the same way.

If I attempt a low speed, low height backflip and crunch my tail mount, fix it, then break it again doing the exact same thing, I know that's how tail mounts break, and I either drive faster, jump higher, or don't attempt a flip when I can't complete one. Nothing is indestructible. Nothing. We have to adapt how we drive to get as much performance out of our vehicles (yes, even bashers) without breaking them. It is how we improve as drivers.

If you are really concerned about the outdrives, grab a set of M2C ones (make sure you get the EXB ones, they are different than standard). Otherwise, it drove really well doing jumps and such, right? Sounds like the truck is awesome, you are just running it sometimes in a way that wouldn't obviously break it, and breaking it. Avoid jabbing the throttle when you have the front on the ground and the rear in the air.
 

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Definitely flexing causing the dB to pop out. I have 5 older non exb 6s Arrmas, each with dozens of packs thru and have never broken an out drive in that spot. Plenty at the cross pin though...
 

Rainger40

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I’m all about accountability and not blaming stupidity or abuse on the truck, but I’m talking less than 5mph speeds and a blip of the throttle to settle the truck. Not landing on one wheel from 10 feet on full throttle. I can’t see any way the out drives should break like this repeatedly at such low torque. I’ll put it back together, again, and share the pics assembled and maybe I’m a big 6s newb that missed something you all can point out to me haha. Thanks
 

Yas

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At full articulation (full droop or full compression) the drive shaft may not be binding when on the bench, but when the arm flexes during running it can. M2C mentions setting the droop properly on the listing for their outdrives. Tighten down your droop screws more. If you've broken two in the same place, that's tell tale signs something needs adjusting 👍
 
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I’m all about accountability and not blaming stupidity or abuse on the truck, but I’m talking less than 5mph speeds and a blip of the throttle to settle the truck. Not landing on one wheel from 10 feet on full throttle. I can’t see any way the out drives should break like this repeatedly at such low torque. I’ll put it back together, again, and share the pics assembled and maybe I’m a big 6s newb that missed something you all can point out to me haha. Thanks
High torque, not low. IIRC electric motors make maximum torque at low RPM. Non-sensored brushless motors have to be rotating already to overcome existing load, but if you are rolling at slow speeds, that isn't an issue. That is one of the reasons why rolling backflips are more impressive than standing backflips.
 

Rainger40

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New outdrive in, tightened diff screws and it’s locked solid. Un-tighten and it moves again. I’ve opened and closed it 10 times and don’t know what’s up. Everything is seated and moving freely even with the lid on, just not tightened. Any ideas. I swear I routinelay work on complicated heavy equipment worth 100’s of thousands of dollars and this little truck is just giving it to me at every turn haha.
 

Rainger40

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Well I would’ve bet money it all went back the same and to my eye I swear the lsd play was the right way, but I flipped the top plate(actuall rebuilt whole diff then flipped top) and viola it works. So I guess that headache I earned myself haha. so it’s all back together now, where do you recommend droop. I’ve got it set just past level with chassis. I went full compression and then some until squeaks and creaks made me think I’d break it and the results are in the pics below. What you all think? Destined for success or good thing I’ve got 2 more out drives in a bag (gosh I hope not this)? Also I know my sway bar mount is cracked, another is on its way.

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Notorious J

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Well I would’ve bet money it all went back the same and to my eye I swear the lsd play was the right way, but I flipped the top plate(actuall rebuilt whole diff then flipped top) and viola it works. So I guess that headache I earned myself haha. so it’s all back together now, where do you recommend droop. I’ve got it set just past level with chassis. I went full compression and then some until squeaks and creaks made me think I’d break it and the results are in the pics below. What you all think? Destined for success or good thing I’ve got 2 more out drives in a bag (gosh I hope not this)? Also I know my sway bar mount is cracked, another is on its way.

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I actually like to set my droop so the arms are flat on a 90 to the bulk head. It's a bit of reduced travel, but that helps save shock ends and gives a little more room for the flex in the arm. Those wheels are heavy and pull down hard on the arms when in the air. Not saying my set up is perfect, but I've had a lot less issues in the front since setting it up that way.
 
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