Outcast My findings on the 4s arrma V2 chassis problem.

[Surchaufeur]

I have taken apart my outcast 4s v2 and decided to try and take care of it. The issue i keep seeig is the A arms being too strong and it rips the hinge pin, bents it and destroys the chassis in the process. Went ahead and shaved material around the hinge pin hole in arm.

They increased the thickness to 12mm from 10mm from the v1. Sanded it down to 10mm. Made a few holes in the middle of the arm and boiled them in water. The arms are more flexible now. I want the arms to fail before it makes the chassis fail.

Edit: I find doing this to be unnesessry now with the hinge pin fix and upgraded bracket. You can do it but i feel like its not needed/worth doing anymore. I did it at the time for experimentation when i was trying to find solutions by using the original rounded pins until i found the longer ones at my hobbyshop.

I was putting my truck togueter and i noticed the hinge pins that ckme on the v2 have rounded ends. The v1 and v2 have the same lengh of 62.8mm byt the rounded ends i believe makes the hinge pin holderbcompletely useless. My rear hinge pin on my v2 has a diameter of 4.5mm vs my 5 year old one i still have has a diameter of 4.1mm. So the QC seems to be off on hinge pins supports. The front one has 4.1mm diameter

Getting aftermarket hinge pin supports and new hinge pins i believe will help greatly against the issue. I went a step further by weakening the arms in my case.

 

[hobo]

nice nails

 

[Surchaufeur]

nice nails

I make people jealous. I giggle when i see fake long nails. They getting chopped soon if they don’t chip.

 

[Shifty Wanker]

Interesting info... I just had this happen on my Kraton 4s v2. The arms are indeed too strong and will rip out the hinge pin. I can't even get a hold of a new chassis at the moment. they've been backordered for a long time.

 

[Tex Koder]

I have taken apart my outcast 4s v2 and decided to try and take care of it. The issue i keep seeig is the A arms being too strong and it rips the hinge pin, bents it and destroys the chassis in the process. Went ahead and shaved material around the hinge pin hole in arm.

They increased the thickness to 12mm from 10mm from the v1. Sanded it down to 10mm. Made a few holes in the middle of the arm and boiled them in water. The arms are more flexible now. I want the arms to fail before it makes the chassis fail. View attachment 288210View attachment 288211View attachment 288212

I was putting my truck togueter and i noticed the hinge pins that ckme on the v2 have rounded ends. The v1 and v2 have the same lengh of 62.8mm byt the rounded ends i believe makes the hinge pin holderbcompletely useless. My rear hinge pin on my v2 has a diameter of 4.5mm vs my 5 year old one i still have has a diameter of 4.1mm. So the QC seems to be off on hinge pins supports. The front one has 4.1mm diameter
View attachment 288213View attachment 288214View attachment 288215View attachment 288216View attachment 288217View attachment 288218View attachment 288219View attachment 288221
View attachment 288222
Getting aftermarket hinge pin supports and new hinge pins i believe will help greatly against the issue. I went a step further by weakening the arms in my case.

Instead of shaving/sanding , drilling holes and boiling the arms..
Just use a Dremel & cut a 1-2mm slot (or wider) in the arm's pivot areas ,like so >>

Basically making it a double split-hinge system to allow for it to 'break easier'..

 

[Jluther@becoinc]

Instead of shaving/sanding , drilling holes and boiling the arms..
Just use a Dremel & cut a 1-2mm slot (or wider) in the arm's pivot areas ,like so >>

View attachment 288245

Basically making it a double split-hinge system to allow for it to 'break easier'..

It’s expensive but M2C makes a great chassis brace that stops the chassis break issue. I bought one and I’m sure it has paid for itself more than once.
I broke four before installing it and haven’t needed one since. I also put shoo goo down in the bottom of the chassis around where the steering posts go in. The black tubes in the photo are for the clips on the skid plate to go in from underneath. My chassis breaks have all been across the steering post area.Have you guys had the ears that hold the hinge pins break by themselves? I’m trying to get why y’all would make your arms weaker on purpose.

 

[Surchaufeur]

Instead of shaving/sanding , drilling holes and boiling the arms..
Just use a Dremel & cut a 1-2mm slot (or wider) in the arm's pivot areas ,like so >>

View attachment 288245

Basically making it a double split-hinge system to allow for it to 'break easier'..

That would make them significantly weaker

 

[Surchaufeur]

The arrma 4s hinge pin on the v1 and v2 are the same but it looks like they changed when they went from the old packaging to the new one. They seem to have also went from a zinc alloy to bare steel.. my v1 hinge pins have no spot of rust after 4 years of running vs already rusted on the v2 with no wet running(4-5) packs.

Found the part at my hobbyshop but it has the same issue with the rounded ends. But we found an hinge pin who is 0.5mm longer according to the packaging and the ends are not rounded off. So it should be a great win and a direct replacement who should strengthen the chassis a lot in that area. More info coming soon. Im going home

It’s expensive but M2C makes a great chassis brace that stops the chassis break issue. I bought one and I’m sure it has paid for itself more than once.
I broke four before installing it and haven’t needed one since. I also put shoo goo down in the bottom of the chassis around where the steering posts go in. The black tubes in the photo are for the clips on the skid plate to go in from underneath. My chassis breaks have all been across the steering post area.Have you guys had the ears that hold the hinge pins break by themselves? I’m trying to get why y’all would make your arms weaker on purpose.

View attachment 288267

View attachment 288268

This is the reaskn. Ur chassis reinforcement wont save ur chassis from this breakage unless u do something bht i believe to have found a less drastic solution

I edited the original thread to include these pics

 

[Surchaufeur]

Here ia rhe original pin If i had to guess the pins started to have the issue when they went from the old packaging to the new one. On the amainhobbies website its the pins are rightly made and were on the old arrma packaging

I received my KCRC upgrades. My first ever parts from them. The bracket is 0.3mm thicker vs stock.

The new pins that are 0.5mm longer is AR330731. A direct fit and gives a lot more support and strenght now with the aluminum reinforcement specially now that it is thicker and 7075 T6. It clears the skidplate also like if it was made for it...i don't like how affma uses screws that go trough the skid and trought the hinge pin bracket and then into the chassis. My screws were bent after a few hits. There was no issue with the v1 skidplate mounting system so i decided to directly use countersunk screws to attach the brackets.

Here is a comparaison with the v1 hinge pin vs v2 with the KC RC hinge in and you can definetly see the problem

 

[Velodromed]

Here ia rhe original pin If i had to guess the pins started to have the issue when they went from the old packaging to the new one. On the amainhobbies website its the pins are rightly made and were on the old arrma packaging View attachment 289346
I received my KCRC upgrades. My first ever parts from them. The bracket is 0.3mm thicker vs stock.
View attachment 289352
The new pins that are 0.5mm longer is AR330731. A direct fit and gives a lot more support and strenght now with the aluminum reinforcement specially now that it is thicker and 7075 T6. It clears the skidplate also like if it was made for it...i don't like how affma uses screws that go trough the skid and trought the hinge pin bracket and then into the chassis. My screws were bent after a few hits. There was no issue with the v1 skidplate mounting system so i decided to directly use countersunk screws to attach the brackets.View attachment 289353View attachment 289351View attachment 289350View attachment 289349View attachment 289347
Here is a comparaison with the v1 hinge pin vs v2 with the KC RC hinge in and you can definetly see the problemView attachment 289348

Nice job on figuring this out! I’ll look at my builds and see if any of this applies. Since I built them from scratch I did things a bit differently. The 3s line has the pin bracket screwed straight into the bulk head. I did not like how the it went through the 4s skid so did it the old way. I’ll have to look at the pins though, what you’re saying makes sense.

I’ve broken 2 lwb chassis so far, neither were at the arm interface. The main issue I see is weight and power. They simply increased the length of the chassis, not the strength. One of mine has the standard LWB chassis and it’s broken twice, it can’t handle 4s parts and power, just like the two 4s new chassis. I installed the m2c LWB chassis brace the other day and love it, hopefully it helps. My other build is on a swb chassis with 3s towers and v1, 4s rpm arms. It’s super sturdy.

 

[Surchaufeur]

Nice job on figuring this out! I’ll look at my builds and see if any of this applies. Since I built them from scratch I did things a bit differently. The 3s line has the pin bracket screwed straight into the bulk head. I did not like how the it went through the 4s skid so did it the old way. I’ll have to look at the pins though, what you’re saying makes sense.

I’ve broken 2 lwb chassis so far, neither were at the arm interface. The main issue I see is weight and power. They simply increased the length of the chassis, not the strength. One of mine has the standard LWB chassis and it’s broken twice, it can’t handle 4s parts and power, just like the two 4s new chassis. I installed the m2c LWB chassis brace the other day and love it, hopefully it helps. My other build is on a swb chassis with 3s towers and v1, 4s rpm arms. It’s super sturdy.

Adding a 6s steering bushing on the tower to tower tube to add preload on the rubber damper is a good thing to do. Because from factory the rubber damper has no preload and pretty much useless until the chassis flexes considerably. U would be surprised how Much 7075 t6 flexes but u should Be golden on that type of breakage with the m2c Reinforcement

 

[MikeM]

I have taken apart my outcast 4s v2 and decided to try and take care of it. The issue i keep seeig is the A arms being too strong and it rips the hinge pin, bents it and destroys the chassis in the process. Went ahead and shaved material around the hinge pin hole in arm.View attachment 289311View attachment 289312View attachment 289313

They increased the thickness to 12mm from 10mm from the v1. Sanded it down to 10mm. Made a few holes in the middle of the arm and boiled them in water. The arms are more flexible now. I want the arms to fail before it makes the chassis fail. View attachment 288210View attachment 288211View attachment 288212


I was putting my truck togueter and i noticed the hinge pins that ckme on the v2 have rounded ends. The v1 and v2 have the same lengh of 62.8mm byt the rounded ends i believe makes the hinge pin holderbcompletely useless. My rear hinge pin on my v2 has a diameter of 4.5mm vs my 5 year old one i still have has a diameter of 4.1mm. So the QC seems to be off on hinge pins supports. The front one has 4.1mm diameter
View attachment 288213View attachment 288214View attachment 288215View attachment 288216View attachment 288217View attachment 288218View attachment 288219View attachment 288221
View attachment 288222
Getting aftermarket hinge pin supports and new hinge pins i believe will help greatly against the issue. I went a step further by weakening the arms in my case.

So also if you buy the 6s pins they’re just a tad longer when I broke mine the 1st time the pin bent an I had a good 6s here an it’s worked great wasn’t til later I learned I should’ve replaced the pin retainer as well

 

[Surchaufeur]

So also if you buy the 6s pins they’re just a tad longer when I broke mine the 1st time the pin bent an I had a good 6s here an it’s worked great wasn’t til later I learned I should’ve replaced the pin retainer as well

The 6s ones have to be cut to fit inside the skidplate. This is a direct fit

 

[Tex Koder]

That would make them significantly weaker

You can always cut a thinner slit..
My drawing was ONLY for illustration purposes.. it wasn't meant to be exact width.

Any how, the slit idea is much easier to do than trying to shave down (to 10mm) the hinge area ; drilling More hole(s) in the arms ; AND giving them the old medieval hot boiling bath routine -to soften them up...

But, who am I to say..
Some folks like the Extra Work/Challenge

 

[Mikeeeeeeeeeeeeeeeal]

Cool thread. Several perspectives.

What I can't wrap my head around is how an additional op would occur at manufacturing. First thought was it was happening on the truck but that's not the case.

How about left in a tumbler way too long, but that would have to be really aggressive media and left in for way too long.

 

[Surchaufeur]

You can always cut a thinner slit..
My drawing was ONLY for illustration purposes.. it wasn't meant to be exact width.

Any how, the slit idea is much easier to do than trying to shave down (to 10mm) the hinge area ; drilling More hole(s) in the arms ; AND giving them the old medieval hot boiling bath routine -to soften them up...

But, who am I to say..
Some folks like the Extra Work/Challenge

This guy chassis broke but he made a hinge pin retainer out of steel + longer pins the chassis was already broken but its the arm who broke afterwards. This proves why the chassis is ripping is because of the pins

You can clearly see the chassis is broken but its the arm who broke after the modification

 

[Mit Snori]

So - summing up - fit longer hinge pins and stronger hinge pin holders and you should be in better shape? Agreed?

 

[Velodromed]

Adding a 6s steering bushing on the tower to tower tube to add preload on the rubber damper is a good thing to do. Because from factory the rubber damper has no preload and pretty much useless until the chassis flexes considerably. U would be surprised how Much 7075 t6 flexes but u should Be golden on that type of breakage with the m2c Reinforcement

I agree there! When I put together the tower to tower brace on all old Yeller I did not use that silly rubber bumper. I put in several hard silicon washers instead. On Thing I used a solid aluminum bar (made by TBone racing) for the tower to tower brace.

 

[MikeM]

The 6s ones have to be cut to fit inside the skidplate. This is a direct fit

Well I’m telling you I put 6s pins in mine you DO NOT HAVE to cut them in anyway yes they’re are longer but fit perfectly

 

[Velodromed]

[/QUOTE]
I just realized

I’ve broken 2 lwb chassis so far, neither were at the arm interface.

I totally was wrong!! My last chassis break is related to the ‘pin issue’. It hit me when I was looking at the pictures that I took at the time (below). I need to think on this. Along with your above ideas, I wonder if drilling the pin hole a few mm deeper and using the 6s pins would help. Or maybe even longer pins are needed. Yeah, I gotta think in this.