Kraton How important is it to shim the diffs ?

stonyrc

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I have a new Kraton I bought a month or so ago . It is the V2. How important is it to shim its diffs ? I changed the center diff fluid to 100k and that's the extent of what I've done to it. I'm installing the orange springs (front and rear) this week. I've run it over grass(6s) a few times and that's about it. Please keep your responses to personal experience only. Your opinion is just that w/o actual experience with this exact truck. Not trying to be offensive at all I just want accurate info. Thanks
 

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@stonyrc obviously the truck will work just fine without shimming the differentials. Just like your full size car will run without every changing the oil. But just like the full size car eventually things will wear out and most likely more prematurely than otherwise.

So yes if you want to make your diffs last as long as possible then it's important to shim your diffs. If you don't mind replacing them whenever they wear out then keep doing what you're doing. :D
 

stonyrc

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So how often do they need to be shimmed ? Right out of the box or approx how soon after a certain amount of runs ?
 

dpricenator

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My experience was a broken servo early on, due to driver error. The Kraton was on the workbench waiting for the parts, and I read through everything here, and then won a full set of replacement bearings. So since everything had to come apart for the bearings, I decided to go ahead and Shim the diffs. I had not had a differential issue ever, and have seen multiple people with shredded gears, cracked gears, gears in 2 or pieces, etc. I am not a good driver, meaning I can't tell you if I am on the gas or off, when I land a jump. I pretty much floor it when ever I want to go. And pretty much slam on the brakes when I want to stop. Some times both in a matter of seconds. Wet pavement offers a ton of drifting opportunities, but because it 4WD, I need lots of speed, slam a turn and the brakes at the same time, then slam the gas again. My diffs are solid.

Is it a Pain in the A$$? Heck yeah. I suggest buying a power screwdriver, and a good little set of hex bits. It will make the process less painful, and save your hands from cramping up. I can't imagine doing all 3 diffs with the stock "L" shaped Hex key that comes with the kit. The Bulletproofing the diffs on a Senton Video, on you tube is the best to follow.


 

dpricenator

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So how often do they need to be shimmed ? Right out of the box or approx how soon after a certain amount of runs ?

Being new again, to the RC world, I took mine out of the box and ran it. Now I think I will take any new RC I get and either build the kit correctly the first time, or do the good preventative maint right out of the box. I would hate to see you bash it for 3 weeks, start to learn to drive it, and then shred the diffs, and possibly tear up something else. I think the Diff shims, Springs, and servo Mount are the 3 MUST DO mods on this car.
 

stonyrc

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Ok thanks. I'll check out that video.

What's funny about this is that I had a hpi savage flux I ran/bashed atleast 25 times and never shimmed the diffs. I never shred any gears or had diff issues. I ran it with 6s all the time as well.
 

Vanning

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Ok thanks. I'll check out that video.

What's funny about this is that I had a hpi savage flux I ran/bashed atleast 25 times and never shimmed the diffs. I never shred any gears or had diff issues. I ran it with 6s all the time as well.

That's because the HPI diffs are shimmed already.

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If anyone is having a hard time getting shims.... it's worth calling up one of these custom shim companies. Or just send s request for an estimate. Some of those places will make a low quantity or whatever you need.
 

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Ole Fart51

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I was a firm believer in shimming my diffs, I have done it to all my Arrma trucks. But when I bought my Kraton, I decided not to shim just to see how long it would last. Not one single problem with my diffs. I'm not really sure it's necessary.
 

chevys10zr2003

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I was a firm believer in shimming my diffs, I have done it to all my Arrma trucks. But when I bought my Kraton, I decided not to shim just to see how long it would last. Not one single problem with my diffs. I'm not really sure it's necessary.
I don't know if I would say that it isn't necessary. I think it's more on a vehicle to vehicle basis. Maybe it's manufacturing tolerances. I don't know for sure. I know that my Kraton and my Typhon haven't had any problems while my Senton had an issue with the center diff. Meanwhile my two buddies with Typhon's had issues with them until they shimmed them. I guess if you want to be safe and possibly save money in the long run, go ahead and shim them. If you're bored and like fixing things, let them go and see what happens.
 

lonee

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.. It is not easy to explain for me in english, but I´ll try..
Maybe I took the wrong words, if it is, please correct me.

The sense of shims is to get the gears (there tooth) in an optimal position where were out is minimized.
Also i makes sense with older diffs which where warn out a little. (moving the gears a bit more together that the teeth will fit perfect to each other) Maybe you can say It is a kind of adjustment of the gears.
If the cone gear moves too far outwards, it will be stripped and will also damage the hole diff.
Thats I do also in my job on printing machines.
 

Vanning

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I felt that the shims helped the O-rings out more than anything . You can pack the o-ring area with green slime, put a thin shim over it, then the pin. This way the pin rides on the shim rather than against the o-ring and the side of the diff case. Less leaking silicon this way because the grease is samiched behind the shim.
 
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RCpete

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SHIM THE DIFFS! Especially the Arrma 1/8th vehicles, and i mean shim the internals and shim the whole diff in its gear casing by placing shims on the outside of the bearings. This reduces the slop which is quite noticeable on the Arrma 1/8th's. You really don't want movement in the diff as you will break teeth on the crown or pinion gears. Same with the internals, loads of play with the out drives so they also need shimmed.
 

Derrick 0511

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Hi Stony,
I own the Kraton v1 and have continuously upgraded it, so now it is more a v2 plus additional upgrades. However you asked for specific feedback especially for this truck, and as far as the diffs go v1 and 2 are similar. I was a newbie too and ran my Kraton the first 8 month without doing anything to the shims. I run it mostly on tracks and sometimes for bashing. On the beginning everything was fine running on 4 and on 6S. After a while the rear Diff went of, then the front Diff after 5 or 6 more runs. And eventually the center Diff. So several occasions where I had fixed one Diff and again had to stop because next Diff kissed goodby. I rebuilt them all acc. To manual specs and filled the center Diff with 100 K allowing more wheelies and so. After that the front and rear Diffs really went down on reliability especially on 6 s. If you tighten the center Diff, the torque will be distributed stronger to the wheels that have teacktion compared to a lighter center Diff. Which will allow the power to be distributed to the wheels without tracktion and allow the torque to bleed out in fast spinning ballooning tyres withou tracktion, limiting the max torque which needs to be transferred. Once i put in the 100k in the center Diff I could literally what the front and rear Diff popping the cloggs every 6 to 8 runs. It was then I decided to give the shimming a try. i did that 6 month ago and have never had an issues since then. Even on Wheelies, hard braking from full speed to stop or what so ever. So on a nutshell I would definitely recommend to do internal shimming (shims in the cage into of the o rings) and external shimming (inlet gear and on one or two side of the bearings. Make sure that a minimum play i still guaranteed and the gears are not running too tight afterwards. You can determine this by turning the Diffs with hand. If you feel a little resistance and the gears meshing unsmooth that means too much shims in. Take one out again should that be the case. If you build the Diffs internals and are new to it. I recommend to put the shims in and tighten the screws without putting any Diff fluid in. If it's too loose or too tight you will have to open them again and get it right, -and it is just a mess if you have all that oil Messing around. One you have it right. Put the oil in and do final assembly. Hope this helps best regards Derrick
 
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Out of box brand new I took all diffs apart an shimmed, also needed to add two more shims to outside diff at bearing,,rear had more play in it then front. Show me how well plastic parts are to duplicate an match up..Also went with HR housing all around, changed pinion to 15 right away when center diff was out. had to apply heat to break lotite at aluminum points.also added HR center stand. Another thing is if your running grass off road an can't see the high an low spots in the yard or field,drop the tbone bummper off,it's a flip scoop.
 

Timritchieblue

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I built my Roller with shimed diffs soon as I got the truck, I have had 0 failures running 6s with a 1480kv motor.
 
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