My Kraton 8s garage build

[Jimbobjr]

I picked up my k8s yesterday and going to start a thread here about what I plan to do to it. First thing, I must say is this truck is really really nice. Build quality, fit and finish is better (at least mine) than my 6s vehicles. One shock is leaking though...There are a couple low cost tweaks I see which can be done. I might, down the road make a chassis but plan to just stiffen this set up.

First is super simple. 16x12mm carbon fiber tubing fits right over the braces. Nice and tight slip fit. This stuff is super strong, stiff and will add a lot of support without adding much weight. Also making 7075 skids and extending them to the next bolt hole on the chassis.

The car is fine with the motor it comes with but before you even put a battery in, increase the punch, and find a 23t (maybe bigger) pinion. It is not exciting out of the box. I’m going to change to a 5692 Hobbystar motor but no 8mm pinion yet. This will compensate for the trucks portly size. The smaller motor pictured is similar size to stock (4585). Rcjuice had a cyber Monday sale in I could not resist a 5692 motor for $102 shipped.

 

[bicketybam]

Very nice! Congrats!

 

[LibertyMKiii]

The 56xx motors are awesome. How much length will fit in there? I had the TP Power 5670 (56x106mm) it was insane to say the least! It could shred XMaxx diff gears on command

Can't wait to see what you do with this build. I enjoy seeing the machine work you do!

 

[bicketybam]

I was told a 56113 will fit and that's what I'm going with once the mount is available ???

 

[WoodiE]

Looking forward to seeing more of your Kraton 8S build @Jimbobjr

 

[adidas303]

Gratz!! I shall be following along with the build!!

 

[Camaroboy383]

I picked up my k8s yesterday and going to start a thread here about what I plan to do to it. First thing, I must say is this truck is really really nice. Build quality, fit and finish is better (at least mine) than my 6s vehicles. One shock is leaking though...There are a couple low cost tweaks I see which can be done. I might, down the road make a chassis but plan to just stiffen this set up.

First is super simple. 16x12mm carbon fiber tubing fits right over the braces. Nice and tight slip fit. This stuff is super strong, stiff and will add a lot of support without adding much weight. Also making 7075 skids and extending them to the next bolt hole on the chassis.

The car is fine with the motor it comes with but before you even put a battery in, increase the punch, and find a 23t (maybe bigger) pinion. It is not exciting out of the box. I’m going to change to a 5692 Hobbystar motor but no 8mm pinion yet. This will compensate for the trucks portly size. The smaller motor pictured is similar size to stock (4585). Rcjuice had a cyber Monday sale in I could not resist a 5692 motor for $102 shipped.
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I sincerely look forward to this build! Love what you do sir, and cant wait to see what you come up with.. as per your notion and my response on the short chassis braces..

I got to take a close look at one, I feel it is possible to get them to the floor of the chassis.. the issue being the center shaft.. I was thinking a 10-11 mm wide 7075 brace that steps out roughly 25-30mm (I did not measure anything) above the shaft.. you could then machine out the center for the shaft, essentially making two legs that extend down to the chassis plate on each side of the shaft..

Just think of it as the 6s braces, but with a double leg at the bottom.. pop and counter sink a couple holes in the chassis and bingo... that would be ideal imo.. now with the open hinge point on the center diff case you could machine a bracket that goes from that hinge point back up to the factory t2t brace if you wanted to prevent it from yielding under load.. you would obviously have to devise a way to secure the top portion to the brace, wether through bolted with machined half rounds, or a clamped half round..

Sorry for the ramble.. just thinking out loud.. look forward to what you come up with..

 

[Lride Chart]

I picked up my k8s yesterday and going to start a thread here about what I plan to do to it. First thing, I must say is this truck is really really nice. Build quality, fit and finish is better (at least mine) than my 6s vehicles. One shock is leaking though...There are a couple low cost tweaks I see which can be done. I might, down the road make a chassis but plan to just stiffen this set up.

First is super simple. 16x12mm carbon fiber tubing fits right over the braces. Nice and tight slip fit. This stuff is super strong, stiff and will add a lot of support without adding much weight. Also making 7075 skids and extending them to the next bolt hole on the chassis.

The car is fine with the motor it comes with but before you even put a battery in, increase the punch, and find a 23t (maybe bigger) pinion. It is not exciting out of the box. I’m going to change to a 5692 Hobbystar motor but no 8mm pinion yet. This will compensate for the trucks portly size. The smaller motor pictured is similar size to stock (4585). Rcjuice had a cyber Monday sale in I could not resist a 5692 motor for $102 shipped.
View attachment 56202View attachment 56203View attachment 56204View attachment 56205View attachment 56206

Congrats and sounds like you are right there with the upgrades I was thinking. Excited to see the end result.

 

[arrmadillo]

The mad fabricator is at it again. ?

 

[bicketybam]

I know M2C's brace system will go to the chassis ??? That's for all us unskilled guys ? I wish I could do what you do ???

 

[Jimbobjr]

For the 56xx motors, there’s a lot of room behind the hobbywing 87 or the hs 92 so the 113 should be no problem. There may be a need for a fan for these. I never ran a fan and thought they were just one more thing (for a basher anyway...) until I knocked off 30-40degrees off the 4985 hobbywing with fan setup I made. Really like the one that comes with the k8s. We will see how they hold up. Maybe there’s a way to make it work on the 56mm can.

I’m looking forward to what m2c comes up with for a bracing system and motor mount. Weight is the real enemy with this rig. The towers, shocks, arms, and drive train are going to take a beating adding even more weight to this thing. I will most likely make basically the same chassis but 7075. Can’t do the gussets in the center though.

Bracing is tricky with this as @Camaroboy383 said above. Good thing is there’s a lot of chassis there. Some of thetruggy race rigs will have two braces on either side or just one heavy off center one. For now it will just be the stock chassis with the above mentioned mods. After that we will see what else the other guys and myself are breaking and go from there.

I would love to make a full length brace like a bridge truss all one piece attached to the motor mount in the center. One thing I know is it’s getting cold in the garage so this will be a slow build.

 

[Full Throttle R/C]

Congrats ?looking forward to your build?

 

[BashingBrian]

Can't wait to see what you turn this into, as said above your machining skills are awesome and I know I can't wait to see what you come up with..???

 

[Jimbobjr]

Order some 7075 Aluminum for the chassis and braces. Going with 5mm which if I did my calculating right will add 6 or so ounces. 7” x 24” x .190” (stock is .158 and 6061) Braces will be tricky, I wanted to think it over some more but Online metals had a 25% off sale that ended last night so I ordered some 1/2” x 4 1/2 wide bar which might work in a variety of whys so hopefully I can use it.
Tricky part is getting the braces bolted tight to the chassi and drive support with the drive shafts in the way. Lots of options but it all needs to be serviceable. The front and rear part of the brace will be one piece and connect to both pins at the same time instead of the top and bottom not being attach to one another. I made a sketch but it’s out in the garage. The top brace will attach to this brace one each end which will need to be easy to take off to get to the center dif. I might just be worth making 3 stronger braces that just drop in where the stock ones are...
I was going to wait and see what m2c was going to make before starting in case I miss something but decided to just be confident in what ever I come up with in my head. Their stuff is killer though, I have their motor mounts and a couple chassis's.
The drive unit and esc/servo mount is really nice, I wonder how it will hold up though. Plastic on this model (at least this part, battery trays and bulkheads) seem to be different than the 6s. Landing this thing on its lid might pull all the threads out of this stuff. About the only thing that I’m not crazy about is the battery trays. They are high on both ends so if you are using soft case lipos it puts stress on the wires. And those straps, you guys with hotdog fingers are going to have a tuff time. Plastic sides are huge, even my little girly fingers have trouble. I think I will look for longer straps so I never have to let the strap go thru the buckle.
Jim

 

[Jimbobjr]

As you can see there’s a lot of room for a big can. I put it all back together, still no 8mm mod 1 pinions in my mailbox. Once you crack the lock tite it all comes apart really nice. Little bit cumbersome on the bench.

 

[Jimbobjr]

Stripped it down to the chassis today. My material has arrived so I figured it’s time to start on it. Hate to take it all apart because it means no wheel time for a while. Chassis material is over kill. Very thick, I hope my buddy can bend it with out cracking. He has a multi million dollar fabrication shop so I can’t see why he couldn’t. He could easily make the whole thing...

My sketch for bracing is down below. I’m not an engineer but I figure what I got there will be good enough. If you see something let me know. I think it’s going to be pretty much rock solid. (One block is one inch)

One curve ball I see is the center drive unit is supported by the gussets on each side. I wonder how the big time guys are dealing with that issue. I’m going to machine two pieces of round bar flat on one side, hollow them out and bolt them from underneath.

 

[Camaroboy383]

Looks very promising sir.. I like it!

 

[Notorious J]

Nice to see you getting right to it with the new K8S @Jimbobjr. Loved what you did with the 6s, so definitely fun to follow along with this new build. I'll likely never own one, but great to follow along with all the guys on the forum who have them, and seeing what everyone comes up with to make them "Arrma Forum" tough.???

 

[Jimbobjr]

Looks very promising sir.. I like it!

Nice to see you getting right to it with the new K8S @Jimbobjr. Loved what you did with the 6s, so definitely fun to follow along with this new build. I'll likely never own one, but great to follow along with all the guys on the forum who have them, and seeing what everyone comes up with to make them "Arrma Forum" tough.???

Thanks guys!
The 6s rigs are fun to work on. The platform has been around for a few years and you get to see what everyone else’s successes and failures. The 8s There is not much to go on except your eyes. Anyone fooling around with the k8s will see it is so heavy. Trying not to add to that is going to be hard. Right now the best and cheapest thing one could do is up in my first post. Just put the carbon rod over the braces. It really stiffens them up. Takes like 5 minutes to do. You heard it there first.

The chassis needs to be stiffer. This car will destroy itself on tail and nose landings, even two wheel landings at height. Not sure if just making it out 7075 the same thickness would be enough. Mine is 1mm thicker but no gussets. I may make a few cut outs to make it a little lighter.

The long rear brace is also a potential problem. Not attaching it to the chassis and up high on the drive unit puts a lot of stress on that unit. That brace needs to be secure behind the drive and drive supported as well from that brace. Problem is the drive shaft is right there. I will slot mine to accommodate the drive shaft. It will be weak at that point but with the stiff chassis, several times stronger than what it has now. My tekno eb 48 has a similar setup but does it with two braces.

Front brace has no room to be secured to the chassis. Steering, esc and drive shaft are all in the way. I’m hoping the rear brace will support the drive enough to get away with this.

Top brace will be carbon like I did on the Outcast. That thing has been rock solid and still running the stock chassis. Having it secured to the other two and having one connection not two on the towers it will hopefully hold up under the weight.

The arms on this thing are huge and expensive. I wish they weren’t left and right and just pairs. Maybe rpm will solve this, or maybe a lower right can be modded for the left in a pinch.
Jim

 

[Camaroboy383]

If your worried at all about the grooved area of that rear brace you can simply machine a land on each side of the shaft groove and recess a plate in that side held with screws to complete the structure..