Kraton New Kraton Help Please

justpassedu

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So I received my new Kraton in pretty rough shape and I ordered brand new model from towerhobbies. A few stripped screws into the plastic , all diffs leaking . Nothing I cant fix but I had a few questions and thought maybe you can all help. 1st is - Can you guys turn the front end by hand ? My front end will not turn from left to right unless I power on the vehicle , its like it is binding or possibly the steering servo is designed to only turn when power is on. Also the big red hexes in the pillow ball , should those be very tight or just hand tightened down ? Is anyone running a aftermarket receiver box with any success , my futaba will not fit.
 

OrangeDRAGON

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Most, if not all, of the screws on my Typhon v2 out of the box were over-tightened, on top of that the threadlock they use is more powerful then typical blue locktite. I complained to ARRMA but all they said was send them any parts I damaged/couldnt get apart and they would replace, the problem is my ride would be down for 1week+ waiting for parts, I even offered to temporarily pay for the replacements until they got mine and said they can't do that. I've heard of others getting advanced replacements so I was pretty turned off considering I had bought no less than 3 trucks in the past month from them.

Yes, I can turn my steering while powered off, but it is stiff. If you can't turn yours at all I would check the linkage for binding, one of the screws on top or bottom of the linkage assembly may be too tight.

The set screws that hold in the pivot balls have a hemi-spherical shim and the factory manual states you hand/finger tighten them, then back off 90* If they are too tight the binding will possibly hang the arm up or down, but in the long run you'll simply wear down the hemispherical shim.

I'm running a FlySky FS-GT3C Tx/Rx without any problems, the Rx box is sized for the 'newer' tiny sized receivers that have been out for the past ~5 years. Older Rxs as well as newer ones with telemetry or more channels may not fit.
 

justpassedu

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Most, if not all, of the screws on my Typhon v2 out of the box were over-tightened, on top of that the threadlock they use is more powerful then typical blue locktite. I complained to ARRMA but all they said was send them any parts I damaged/couldnt get apart and they would replace, the problem is my ride would be down for 1week+ waiting for parts, I even offered to temporarily pay for the replacements until they got mine and said they can't do that. I've heard of others getting advanced replacements so I was pretty turned off considering I had bought no less than 3 trucks in the past month from them.

Yes, I can turn my steering while powered off, but it is stiff. If you can't turn yours at all I would check the linkage for binding, one of the screws on top or bottom of the linkage assembly may be too tight.

The set screws that hold in the pivot balls have a hemi-spherical shim and the factory manual states you hand/finger tighten them, then back off 90* If they are too tight the binding will possibly hang the arm up or down, but in the long run you'll simply wear down the hemispherical shim.

I'm running a FlySky FS-GT3C Tx/Rx without any problems, the Rx box is sized for the 'newer' tiny sized receivers that have been out for the past ~5 years. Older Rxs as well as newer ones with telemetry or more channels may not fit.
That sucks after all the trucks you purchased. Sorry to hear that. I have not tried to call or email arrma yet. I guess ill have to take the steering servo linkages apart and check that bc it will not turn by hand from left to right , only when power is on. I also noticed some major flex in the mount when the servo is in use and it hits the esc wire. I was hoping I could to run it out of the box but it looks like the entire truck will have to come apart and be rebuilt now as it looks like it was assembled by a 2yr old. As for my receiver it is pretty tiny but just a touch bigger than the receiver box , ill prob try dremeling it down a bit and see if that helps. I am running a futaba tx/rx .
 

OrangeDRAGON

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The servo mount flex is normal and generally not a problem. GKA ( @gregmbrandt ) makes a really nice aluminum one-piece mount (which I just ordered), search forums for pics or message him to order.

The diffs I don't think leak, I thought the same thing. They spray lubricant on all 8 drive cups at the factory, liberally. It weeps down and finds the lowest parts of the rig, in my case I had oil on the bottom of the chassis plate. When I took my diffs apart they were not leaking, they have a nice rubber o-ring inside as well as a gasket where the cup mounts to the gear. However, if you add shims to your diffs you'll get more life out of them and it also gives you an opportunity to use different diff oil weights.
 

justpassedu

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The servo mount flex is normal and generally not a problem. GKA ( @gregmbrandt ) makes a really nice aluminum one-piece mount (which I just ordered), search forums for pics or message him to order.

The diffs I don't think leak, I thought the same thing. They spray lubricant on all 8 drive cups at the factory, liberally. It weeps down and finds the lowest parts of the rig, in my case I had oil on the bottom of the chassis plate. When I took my diffs apart they were not leaking, they have a nice rubber o-ring inside as well as a gasket where the cup mounts to the gear. However, if you add shims to your diffs you'll get more life out of them and it also gives you an opportunity to use different diff oil weights.
ahh ty for that I thought they all may be leaking as there was allot of liquid lol. I opened the center the other day. It was only filled about half way so I put some 100k in there with whatever the stock fluid was to top it off. It seems to be moving nice and smooth now and did not look like it needed any shims at all, maybe the front and rear do. I also noticed there is no diff gaskets in the center , it just kind of seals together on its own.
 

gregmbrandt

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So with the stock servo ..it will not let you turn by hand ...for some reason all of them are like that ....your best option is to get a new servo ...keep the red one as a back up to a lighter car.....if you have the red esc ...be careful they have a tendency to either die or burn....the motor is strong ...
 

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My diffs do not leak, though Arrma is generous with grease inside the front and rear housings. Only my center diff would take shims, the front and rear had no room for any(ymmmv). There are gaskets in every diff.
Over tightening on the front steering linkage can cause a bind, but not typically. (It would take serious over tightening). The RTR servo is marginal. So check for something wrong. :/ (If you are new to RC it is difficult hunting these issues down)

The after market servo mount is $50 thrown away, though maybe it looks nice. To each their own.
 

OrangeDRAGON

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The after market servo mount is $50 thrown away, though maybe it looks nice. To each their own.
The stock composite servo mount flexes and bends significantly, not just at full turn but also when changing steering quickly. Flex at the servo is force and motion that either doesn't get translated to the linkage or at best is delayed. Switching to a more powerful and/or faster servo actually increase the amount of loss. The one-piece aluminum servo mount, connected directly to the chassis plate results in a nearly complete transfer of force/motion from the servo into the linkage.

While some simply may not care or may not appreciate the loss and/or its effects in driving (which as you stated is your opinion) that does not depreciate the physics (which is not a matter of opinion).
 

GT1

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Yup, everyone has an opinion. The stock mount is plenty strong. I'm sure the aftermarket one is a lot stronger. I was just saying it is throwing away $50.
 

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In engineering, there are times where you need strong and flexible, and times you need strong and stiff. The stock Arrma/Durango mount is strong and flexible. For 2/3's of the people buying Arrma RTR's, that is fine. For those of us that actually want to have precise control of our cars, the Arrma servo mount does not cut it - we need strong and stiff.

Real life - I have a Talion, and my son as a Kraton. Both have beast-mode servos. My son cares not a wit about the servo jumping and jiving while he drives. I do. Ergo, I have an upgraded mount, he does not. Both of us agree, mine has more steering response, even with both are wearing truggy tires.

Is the extra steering precision and control worth $30-$50? That is up to you. But in the racing crowd, there are people spending a whole lot more money, for a whole lot smaller improvements... :)
 

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I have many hours on my typhon now, all at the track. The stock mount is the same one that comes on 'rango racing vehicles. There are no complaints of it not being up to snuff. Now when all the V1 Arrma 6s vehicles came out they had a mediocre radio and invariably the tx came out of the box with the steering rate maxed out, which made the servo want to go way past lock, flexing the whole works, and folks wrongly thought there was something wrong and or weak about the mount. It just isn't so.
 

OrangeDRAGON

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I will agree that many simply see the servo push past the endpoints and assume the flex is the issue, but I don't agree with "other racers don't swap, so it must be fine":
  • The Team Durango racing vehicles (and all race oriented R/C for that matter) desire low-weight parts wherever and whenever possible, some drivers may - and some may not - prefer increased steering precision over the weight difference
  • The TD 1/8 DEX8/T have been out for how long? Appx 1yr? I'm not positive, but I also know they account for a minority 'fraction' of the R/Cs TD/ARRMA sells = less vehicles generally results in less aftermarket parts
  • The DEX8/T has significantly lighter wheels, which means less work for the servo and ultimately less of the servo force is lost in the servo moving
  • The 1/10 scale TD buggies, of which have been around longer, in fact do have aluminum servo mounts (by Exotek) and they are quite popular - and this is on a 'lay-down' servo config which is in itself less prone to flex than our 'stand-up' mount
 

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When I was shopping for my Arrma's, I was info hungry. I read thru both mega threads over on RCTech for the DEX8 and DEX8T. Both threads had lots of references to "how do I brace up this wimpy servo mount". So yeah, the TD drivers ARE complaining.

If the stock mount works for you, then great! like you said, everyone has an opinion, and if you are happy with yours, that is what matters.

My opinion was it was too flexy.

Edit - Oh, and the (flysky) radio on the V1 of the Arrma did have steering DR - which you could use to prevent servo binding. I did with both of my truck. This does not stop the mount from flexing, especially with proper truggy servos with +400oz/in of torque.
 
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