Kraton Do i need to shim my diffs? V3 kraton

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Hey all, I just picked up a v3 kraton, do I really need to shim my diffs and if so how?
Regardless of version, it's always a good idea to take them out and replace the oil with something heavier as well as shim them properly inside the cup and outside for good gear mesh.
 
Regardless of version, it's always a good idea to take them out and replace the oil with something heavier as well as shim them properly inside the cup and outside for good gear mesh.
Is the shimming just to cut down on slop or to make the mesh tighter? I always change my diff fluids when I get a truck
 
Mugen 0206 shim set includes all of the shims required besides the thin shim on left side of bearing which is Tekno.
https://www.ebay.com/itm/401103108196

TEKNO RC LLC 13x16x.1mm, Diff Shims (10)
https://www.amazon.com/dp/B00F8OQ2NC/ref=cm_sw_r_sms_c_api_iylRBb12C4EWP

I use 2-1, 2-1 method behind each set of the planetary gear cross sets.

@Rich Duperbash has a good video of process:

@Thomas P also has a good video of process:
What's the purpose if shimming?
 
What's the purpose if shimming?
To remove excess slop in the spider gears inside the cup and ring/pinion. Most of the arrma 1/8 trucks are pretty heavy and brushless torque is very harsh on diffs. Out of the box, there may be a bit too much gear lash and it's a good idea to check. Just a bit of preventative maintenance to avoid messing up $120 worth of diffs prematurely. Diffs are around $30-$40 on ebay. Or at least the last one I bought was.

I removed all the arrma shims from inside/outside the cup.

I used the mentioned shims in my V2 outcast which was suggested as not needing any.
I used all of the MUGE0206 shims inside the 3 diff cups.

I used 3 of the SWX-101018 shims on the ring gear side on both the front/rear diffs.

For the first weekend, I just ran it as it was out of the box because I was waiting on oil and shims to be shipped. Later that week, the stuff showed up and I tore all 3 diffs down and shimmed them. Just after a weekend of running the arrma shims inside the diff were pretty marred up. The mugen shims felt like they were made out of a much harder material, so guessing they will hold up longer.
 
I think the most important shim is the one one the outside that goes over the outdrive. This tightens the mesh to the pinion gear. With the V3, I don’t think the inside shims are a must. JMHO.
 
I think you have it. It is for both purposes I feel. I run 60/200/30k diff oil front/center/rear for reference. I may switch to 500k center over the winter maintenance.

Why this choice in diff oil weights? What do the lighter/heavier weights do? What do they solve?
 
So lower weight oil in one end biases the power to that end. Why is that helpful? What does that do to handling/performance?

And what about the center diff? What does higher/lower do there?

Thanks for taking the time to explain this to me. If there’s a primer somewhere, please point me to it. I’ve been doing RC for a long time but never messed with diff weights. Now that I have a Keaton and have been reading up on tweaks, I see this is really common so I’m trying to learn more.
 
Thicker in front reduces the front diff from unloading as much and turning the tires into pizza cutters.
 
Maybe I can also help with explaining the differences in diff oil weight. Generally speaking, the thicker the oil the more your diff will be locked. So you will get less diff action. That means for example if you use really thick oil in your center diff (for instance 500.000cst of even 1.000.000cst) the power going to the front and rear will even out. Because the (almost) locked center diff will bind the drive axle going to the front and rear together. When one is turning, the other one will also turn because they are locked together by the diff with the thick oil in it. If you use a diff locker in the center like a lot of high speed onroad RC guys are doing, than there is no diff action at all. So you basically have one axle going from the front to the rear without any play in the center diff. I like to have some play in my center diff, so I use 500K (500.000cst) in the center. The diff is a little locked this way but can still turn. So when I land after a high jump or something the diff can still turn and prevent driveshafts to be bent.

The oil thickness in the front an rear have more to do with corner speed. The info below which I found on the internet explains it better than I do I think:


4.3 Front Differential
Using thicker oil will make the car turn more on power, out of the corner, and accelerate faster. The car will turn less into the corner, as off power steering is reduced. It will feel more stable, and can be easier to drive in bumps. If the car is twitchy and feels inconsistent on a rough track, a good idea is to try a thicker front diff. A thinner front oil will have the opposite effect, less on power steering, more off power steering, less stability. Usually the oils used in the front diff range from 3000-15000. 5000-7000 is a safe bet on all tracks, and that’s what I use most of the time when I’m using a standard front diff. With THE Car it is also possible to use thicker oils as it has so much offpower steering, so 10-15k will work on most tracks.

4.4 Centre Differential
Using thicker oil in the centre diff makes the car accelerate a lot faster, but it can be harder to drive in bumps and on slippery tracks. It gets a bit confusing though, because if the track is soft, and it gets really bumpy, a thicker centre diff can actually make the car skip over the tops of the bumps, and thus it will actually be better and faster. But most of the time, thinner centre diffs are used for blown out tracks. A thick centre diff oil will also make it easier to get on power steering, as the rear of the car can be made to slide out when on power. The centre diff usually has the thickest oil of the three diffs, or the same as the front. The oils used normally range from 3000-20000. A safe bet is 5000-7000. I normally never go below this, because I feel that I loose too much acceleration, specially the first ”snap” when I get on the gas. And I don’t either use thicker oils than 10000 because I’m so aggressive on the throttle, I would fly off the track. Normally, if a thicker centre diff oil is used, the front diff also needs to have thicker oil, so the car still remains stable under acceleration.

4.5 Rear Differential
The rear diff set up is the one that varies the most between different drivers. This is because the rear diff has a big effect on rear traction, and each driver’s driving style determines what oil should be used. It is vital to get the right rear diff oil that suits your driving style, otherwise you will only be fighting your car. Some years ago it seemed like everyone always used the thinnest possible rear diff oils. I think it was because people were used to electric offroad. A thin rear diff oil will make the car have a lot of steering into corners, the car is easy to control when accelerating, even if it’s bumpy. So it seems like the way to go right? Yes and no. One drawback is that the rear can lose its traction suddenly. It will have traction, and then lose it all at once when entering a corner. A thin rear diff suits drivers that brake before a corner, keep a tight line around it, then accelerate hard after the corner, towards the next obstacle. This is not how I drive. I like to control the car a lot with the throttle. A thicker rear diff oil will make this possible, it will be possible to steer the car with the throttle. You can enter the corner aggressively because the rear is very stable, and won’t suddenly lose its traction, it will start sliding in a controllable way. After braking, it is possible to drift on throttle, like a rally car through the corner and onto the next straight. I’m on the gas before the corner, and halfway in the corner, or sometimes even before halfway I’m already on the gas hard.
The thick oil makes the rear tires pull more evenly. On a slippery or bumpy track the car can be too hard to drive. The rear diff oil is normally the thinnest of the three diffs, or the same as the others. The oils used range from 1000-7000. 3000 is a safe bet, no matter what your driving style, or what the track conditions. I nearly always use 4000-5000.
 
Yeah... on a track, probably listen to these guys. For a basher like me, I run associated 100k/500k/100k in my outcast and it seems to do really well. Enough give in the center diff to absorb shock on landings but not so much give that it unloads to the front tires really bad when giving it throttle. Thicker in the front/rear diffs helps power get to the ground when your high centered on a log, rock or something. Then the tire touching the ground still gets a decent amount of power.
 
Thicker in front reduces the front diff from unloading as much and turning the tires into pizza cutters.

It will help with keeping one wheel from unloading when turning under acceleration. It won't help from keeping them both from unloading. That's up to the center diff.
 
I watched all the vids, and spent the $40 on shims before mine even arrived. I added the one additional shim per pair of planetary gears and one under each sun gear and it felt to tight to me. After doing some more reading, it seems that the V3's don't need shimming as often out of the box so I removed the shims I added. I did shim the diff over toward the pinion in the housing and changed the diff oils to 50/500/20 and will check them out after a dozen or so packs are through it and see if it needs it then. The diffs were filled to different levels and I did find a piece of slag metal about 1mm cubed in one of them, so I'm glad I got in there.
 
I read all these posts and I still wondering how exactly to shim on my Kraton V3 to use 6S: does it have to be tight or leave some space ?

Please advise.
 
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