Kraton Running Kraton crown gear in Senton??

linkupipm

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  1. Senton 6s
Hi all

A while back I destroyed the crown gear and the input pinion on the rear diff in my Senton.

Tower (and Hobbyco) were good enough to send me a new one under warranty - however, when it arrived, it didn't fit - the diff was just too fat for the diff housing! Or so it seemed.

I believe I ended up somehow with a Kraton crown gear instead of a Senton one. The Senton and Kraton run almost identical diffs - apart from the crown gear - the Kraton is (apparently) a spiral gear, the Senton a straight gear.

Anyway, I emailed Tower (and Hobbyco) with my woes - explained that the new diff didn't fit and that I suspected I had a too-large crown gear for a Senton. They sent me a new crown - good customer support yes, but another 4-5 week wait for postage to Australia!

I wasn't angry, I just wanted to bash my Senton. Does that make me a bad person? I'm sure if you've read this far, you don't think so.

So I had a wait on my hands - and a decent diff - it was just a bit fat. "If only I could make one of the bearings on the left a bit skinnier this diff might just work?" I thought to myself...

Then I did some googling - the Senton runs bearings 16x8x5 on either side of the r/f diffs - if there were such a thing as a 16x8x4 bearing, I might just get some life out of this diff! It might not be perfect, but I might get a few runs out of it while awaiting the correct diff....

And it just so happens 16x8x4 bearings do exist! I ordered 2 from a local seller (thanks http://plaig.com.au/shop/ !!) and they arrived 2 days later. I slotted one in, replacing the bearing that sits on the left of the crown gear.

And hallelujah! I was back in business. I shimmed the diff in tight, applied a generous dollop of lithium grease, and I've gotten 10 good runs out of this diff thus far.

Since then the new Senton crown gear has arrived from Tower - see the images attached for a comparison of the crown I got first vs the crown I got just last week.

Have I got a Kraton crown gear there?

If I do, I can confirm that a Kraton crown will work in a Senton, with a slimmer bearing on the left of the diff.

If that's not a Kraton gear, can someone explain how/why those 2 gears are so different?
 

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MeesterC

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  2. Kraton 6s
  3. Senton 6s
You can definitely see a difference in them! One is thicker than the other. Now I'm wondering if the kraton gear would be a better upgrade for the senton!?!? Thicker gear means more abuse.....lol.
 

linkupipm

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So this gear has done 10 packs now without issue. It'll get run 11 today after servicing all 3 diffs over the weekend.

All 10 packs were 4 cell with 16t pinion.

I've sent those pics to Arrma also - hopefully they can confirm if it is indeed the Kraton crown gear I'm running.
 

MeesterC

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So this gear has done 10 packs now without issue. It'll get run 11 today after servicing all 3 diffs over the weekend.

All 10 packs were 4 cell with 16t pinion.

I've sent those pics to Arrma also - hopefully they can confirm if it is indeed the Kraton crown gear I'm running.
Please let us know if this is a kraton gear. If so, then should I need one I'll do the same as you and look at it as an upgrade.....
 

Rich Duperbash

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Hi all

A while back I destroyed the crown gear and the input pinion on the rear diff in my Senton.

Tower (and Hobbyco) were good enough to send me a new one under warranty - however, when it arrived, it didn't fit - the diff was just too fat for the diff housing! Or so it seemed.

I believe I ended up somehow with a Kraton crown gear instead of a Senton one. The Senton and Kraton run almost identical diffs - apart from the crown gear - the Kraton is (apparently) a spiral gear, the Senton a straight gear.

Anyway, I emailed Tower (and Hobbyco) with my woes - explained that the new diff didn't fit and that I suspected I had a too-large crown gear for a Senton. They sent me a new crown - good customer support yes, but another 4-5 week wait for postage to Australia!

I wasn't angry, I just wanted to bash my Senton. Does that make me a bad person? I'm sure if you've read this far, you don't think so.

So I had a wait on my hands - and a decent diff - it was just a bit fat. "If only I could make one of the bearings on the left a bit skinnier this diff might just work?" I thought to myself...

Then I did some googling - the Senton runs bearings 16x8x5 on either side of the r/f diffs - if there were such a thing as a 16x8x4 bearing, I might just get some life out of this diff! It might not be perfect, but I might get a few runs out of it while awaiting the correct diff....

And it just so happens 16x8x4 bearings do exist! I ordered 2 from a local seller (thanks http://plaig.com.au/shop/ !!) and they arrived 2 days later. I slotted one in, replacing the bearing that sits on the left of the crown gear.

And hallelujah! I was back in business. I shimmed the diff in tight, applied a generous dollop of lithium grease, and I've gotten 10 good runs out of this diff thus far.

Since then the new Senton crown gear has arrived from Tower - see the images attached for a comparison of the crown I got first vs the crown I got just last week.

Have I got a Kraton crown gear there?

If I do, I can confirm that a Kraton crown will work in a Senton, with a slimmer bearing on the left of the diff.

If that's not a Kraton gear, can someone explain how/why those 2 gears are so different?
Though the teeth look different, can't tell without a teeth upward photo if they are in fact spiral cut. Kraton input gear has 10 spiral teeth, Senton has 13 straight I believe. Unless you swap crowns/inputs in both front and back, I would be careful not to alter matching gear ratios.
 

linkupipm

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Both are 43 tooth gears, and the diameter of the gears is identical - meaning the distance between teeth must be pretty close to identical as well.

I received an email from Arrma today and they have agreed that it looks to be a Kraton gear.

Both Kraton and Senton diffs are running in the same diff housing, so again they can't be that different from each other...

I ran this enormous crown gear again today - 11th run with it, without issue. Next time I open the rear diff I'll take a few more shots, see if anyone can spot the spiral cut on there --

Are there any Kraton owners who could post a pic of their crown gears for comparison?

From images on the net I have not been able to spot anything that looks 'spiraly' on the Kraton gear...

For anyone interested, I sent Arrma the pics above and asked if it is indeed a Kraton crown I'm running - this is what they responded with:

Hi Patrick,


Thank you for the information.


You run log looks mostly positive, that is very good news for us!


We are interested to see that you are successfully running the KRATON main gear in the SENTON model using a different bearing.


Kind regards,


ARRMA HQ
 

MeesterC

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Arrma RC's
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  2. Kraton 6s
  3. Senton 6s
Both are 43 tooth gears, and the diameter of the gears is identical - meaning the distance between teeth must be pretty close to identical as well.

I received an email from Arrma today and they have agreed that it looks to be a Kraton gear.

Both Kraton and Senton diffs are running in the same diff housing, so again they can't be that different from each other...

I ran this enormous crown gear again today - 11th run with it, without issue. Next time I open the rear diff I'll take a few more shots, see if anyone can spot the spiral cut on there --

Are there any Kraton owners who could post a pic of their crown gears for comparison?

From images on the net I have not been able to spot anything that looks 'spiraly' on the Kraton gear...

For anyone interested, I sent Arrma the pics above and asked if it is indeed a Kraton crown I'm running - this is what they responded with:

Hi Patrick,


Thank you for the information.


You run log looks mostly positive, that is very good news for us!


We are interested to see that you are successfully running the KRATON main gear in the SENTON model using a different bearing.


Kind regards,


ARRMA HQ
In the one picture of them side by side from the side, wow a tongue twister, you can definitely see that one gear is thicker than the other. What's up with the talk of spiral cuts? What does this have to do with it? Does it make it any more durable? Less durable? I wouldn't think the cut of the gear would have any resemblance to the working side of it. I'm an automotive technician and I do know that if I replace a gear set in the differential I have to reshim the carrier much the same way you did with the bearing. But from your picture, the thicker gear in my opinion would be of a heavier duty gear in which it could take more abuse.
 

linkupipm

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In the one picture of them side by side from the side, wow a tongue twister, you can definitely see that one gear is thicker than the other. What's up with the talk of spiral cuts? What does this have to do with it? Does it make it any more durable? Less durable? I wouldn't think the cut of the gear would have any resemblance to the working side of it. I'm an automotive technician and I do know that if I replace a gear set in the differential I have to reshim the carrier much the same way you did with the bearing. But from your picture, the thicker gear in my opinion would be of a heavier duty gear in which it could take more abuse.

If it is a Kraton gear - which I think it is - it's meant to have a very very slight spiral to it. This I have not been able to spot.

If someone had a Kraton gear and put up a photo we'd have something to compare it to...

My understanding is that spiral cut gears are stronger... but usually when I think spiral cut, I think of something like this:

https://24palm.com/wa-data/public/shop/products/84/45/24584/images/70152/70152.970.jpg

Kraton is supposedly spiral cut, but nothing like that, a very subtle spiral cut...
 

MeesterC

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  2. Kraton 6s
  3. Senton 6s
If it is a Kraton gear - which I think it is - it's meant to have a very very slight spiral to it. This I have not been able to spot.

If someone had a Kraton gear and put up a photo we'd have something to compare it to...

My understanding is that spiral cut gears are stronger... but usually when I think spiral cut, I think of something like this:

https://24palm.com/wa-data/public/shop/products/84/45/24584/images/70152/70152.970.jpg

Kraton is supposedly spiral cut, but nothing like that, a very subtle spiral cut...
Okay, so here is what I did. I googled if the kraton differential gear was spiral cut or not and came upon this as a factory replacement and it is listed as spiral cut. Not exactly sure as to what I'm looking for though. When I googled images of spiral cut gears the teeth all seem to have a slight curve to them.

Link to picture:
https://www.amainhobbies.com/arrma-spiral-cut-differential-gear-43t-ara310497/p409443

Edit: After looking at the picture more closely and zoomed in further I could see a slight curve in the teeth. I'm guessing this is what we are looking for? Does this mean the gear is spiral cut?
 

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exwhyzed

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Here's a pic of the Kraton diff pinion gear, it does indeed have a slight spiral. So this means the Senton diff pinion gear is not making full contact with the Kraton crown gear. This may not matter since the spiral is so slight, and also that both gears are so beefy, making them very bash-breaking-resistant. I guess then, the Kraton diff pinion can also be put into the senton, which will make the gearmesh more proper. This Kraton crown/diff pinion thing is a really excellent upgrade idea!! and costly of course, as many great mods are.



310498.jpg
 

MeesterC

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  2. Kraton 6s
  3. Senton 6s
Here's a pic of the Kraton diff pinion gear, it does indeed have a slight spiral. So this means the Senton diff pinion gear is not making full contact with the Kraton crown gear. This may not matter since the spiral is so slight, and also that both gears are so beefy, making them very bash-breaking-resistant. I guess then, the Kraton diff pinion can also be put into the senton, which will make the gearmesh more proper. This Kraton crown/diff pinion thing is a really excellent upgrade idea!! and costly of course, as many great mods are.



310498.jpg
Thanks for the picture. Makes sense now. Would be a costly upgrade at the time but think of the money saved from not having to do it as often. This would be a well worth it upgrade in my opinion and if/when the time comes this will be what I'm doing. Seems like a few things from the kraton make for excellent upgrades on the senton.
 

linkupipm

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Just to clarify, I am not running the pinion from the Kraton - only the crown. I make it fit in the senton by using a slimmer bearing on the crown gear side of the diff - an 8x16x4 rather than the stock 8x16x5.

I've ran my senton with this setup 13 times now - 16 tooth pinion, 4s battery.

I'll be opening the rear diff over the weekend, I'll take some top-down pics and see if we can spot the spiral...
 

Alex.tali.1

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To throw in my 2 cents since me and arrma diffs have a love hate relationship I haven't done what you did with the crown only and that's interesting actually with the spiral cut input gear pretty much probably just wore itself into the shape since the cut being so slight if u wear down a spiral it gets straight after the curve in the metal is done I ran different diffs like talion/kraton rear and senton/typhoon front and switched around although I don't recommend it them front wheels had some extra yank haha but like rich said since you didn't change the input gear you didn't affect the gearing Wich is awesome when I get home I will post a few pics of them mix and match so to say
 

Rich Duperbash

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Here's a pic, for what it's worth, of Typhon straight cut gears above, Kraton spiral cut below. Hard to discern spiral cuts on 10 tooth input gear, but they are spiraled to mesh correctly. That little bugger is why I always use at least 2 Kyosho or Tekno bearing shims on the crown gear side to keep them buttoned up snug. The input is usually the first to crap out from my experience anyways.
IMG_20170429_233714479.jpg
 

linkupipm

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Thanks for posting the pics - gave me a very good idea what to look for. I've attached some pics that show the top-down-view of my rear diff, and I think we can confirm I'm running a Kraton Crown.

So:

Kraton Crown will run in Senton F/R diff with Senton input pinion + 8x16x4 bearing on crown side, replacing 8x16x5 bearing (and a few shims to keep it snug - currently I have 6 x .01 shims next to the 8x16x4 bearing)

As far as durability goes, I've gotten 19 runs out of this setup so far, using 4s. The gears mesh well - but they do not run as smoothly as my stock diff in the front. Smooth, but the stock one is silky perfection.

My last 5 runs have all been on a very clean surface, and I have been keeping a close eye on the Kraton crown. I am lucky enough to have access to a basketball stadium at my work - it makes a great drifting surface for the Senton. When I run here, it's basically at full trigger the entire time until I hit LiPo cutoff. This surface is really easy on parts of the truck - no crashing, no jumping, no debris or dust - it does however work the drivetrain very hard from the inside out - the entire run with the trigger at full gas will really put the drivetrain through its paces.

Anyway, I have observed my rear diff a number of times and it is 'going gray' - I run white lithium grease in my diffs, and when I open the front it is as white as when I put it in there. The rear - with the Kraton crown - is graying up - which leads me to believe that the Senton input pinion and Kraton crown are slowly disintegrating each other.

So as to whether this is a good upgrade or not - only time will tell. I've gotten 19 packs with it thus far and will keep this thread posted as to how it holds up. To look at, both the Kraton crown and Senton input pinion seem good and the mesh is still excellent and tight - I hope to get 100 packs with it but we'll just have to wait and see.
IMG_0303.JPG
IMG_0304.JPG
IMG_0305.JPG
 

Rich Duperbash

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Thanks for posting the pics - gave me a very good idea what to look for. I've attached some pics that show the top-down-view of my rear diff, and I think we can confirm I'm running a Kraton Crown.

So:

Kraton Crown will run in Senton F/R diff with Senton input pinion + 8x16x4 bearing on crown side, replacing 8x16x5 bearing (and a few shims to keep it snug - currently I have 6 x .01 shims next to the 8x16x4 bearing)

As far as durability goes, I've gotten 19 runs out of this setup so far, using 4s. The gears mesh well - but they do not run as smoothly as my stock diff in the front. Smooth, but the stock one is silky perfection.

My last 5 runs have all been on a very clean surface, and I have been keeping a close eye on the Kraton crown. I am lucky enough to have access to a basketball stadium at my work - it makes a great drifting surface for the Senton. When I run here, it's basically at full trigger the entire time until I hit LiPo cutoff. This surface is really easy on parts of the truck - no crashing, no jumping, no debris or dust - it does however work the drivetrain very hard from the inside out - the entire run with the trigger at full gas will really put the drivetrain through its paces.

Anyway, I have observed my rear diff a number of times and it is 'going gray' - I run white lithium grease in my diffs, and when I open the front it is as white as when I put it in there. The rear - with the Kraton crown - is graying up - which leads me to believe that the Senton input pinion and Kraton crown are slowly disintegrating each other.

So as to whether this is a good upgrade or not - only time will tell. I've gotten 19 packs with it thus far and will keep this thread posted as to how it holds up. To look at, both the Kraton crown and Senton input pinion seem good and the mesh is still excellent and tight - I hope to get 100 packs with it but we'll just have to wait and see. View attachment 9977 View attachment 9978 View attachment 9979
Glad the pictures were helpful. That's definitely a Kraton crown gear on your diff. It's very normal for diff fluid to turn grey/silver with use. Not sure why front is still white, but I run only silicone oils in my Arrma diffs, use grease in my other RCs. Probably just normal wear and degradation. The bearing shims are probably helping keep your mesh/teeth together. That's cool it's running ok.
 

linkupipm

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Glad the pictures were helpful. That's definitely a Kraton crown gear on your diff. It's very normal for diff fluid to turn grey/silver with use. Not sure why front is still white, but I run only silicone oils in my Arrma diffs, use grease in my other RCs. Probably just normal wear and degradation. The bearing shims are probably helping keep your mesh/teeth together. That's cool it's running ok.


I run silicone oil in the diffs also - I run white lithium grease outside the diff, between the crown and input pinion gears - this is where it is 'graying up' - so front (stock) diff is staying white, rear (kraton crown) is discoloring. I'm talking just about outside the diff, in the diff housing, not in the internal part of the diff where the spider and planetary gears live...
 

Rich Duperbash

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I run silicone oil in the diffs also - I run white lithium grease outside the diff, between the crown and input pinion gears - this is where it is 'graying up' - so front (stock) diff is staying white, rear (kraton crown) is discoloring. I'm talking just about outside the diff, in the diff housing, not in the internal part of the diff where the spider and planetary gears live...
Sorry bro, think I misunderstood you referring to internal vs external diff gears with the grease. I haven't tried white lithium on the crown and input gears, just stuck with TrakPower gear grease, seems to do OK. Almost tried Mobile 1 red Synthetic 1/1 auto grease, but it's very thick. Kind of off subject, here's a pic of my first chain link fence back flip attempt with SRT Terrain Crushers...Lol. Fronts grabbed the fence, lost 5 teeth off the input, 1/2 tooth off the crown. Talk about stupid s..t!!!....Lol.
IMG_20170428_203133855.jpg
IMG_20170302_201620578.jpg
 

Don mercier

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Thanks for posting the pics - gave me a very good idea what to look for. I've attached some pics that show the top-down-view of my rear diff, and I think we can confirm I'm running a Kraton Crown.

So:

Kraton Crown will run in Senton F/R diff with Senton input pinion + 8x16x4 bearing on crown side, replacing 8x16x5 bearing (and a few shims to keep it snug - currently I have 6 x .01 shims next to the 8x16x4 bearing)

As far as durability goes, I've gotten 19 runs out of this setup so far, using 4s. The gears mesh well - but they do not run as smoothly as my stock diff in the front. Smooth, but the stock one is silky perfection.

My last 5 runs have all been on a very clean surface, and I have been keeping a close eye on the Kraton crown. I am lucky enough to have access to a basketball stadium at my work - it makes a great drifting surface for the Senton. When I run here, it's basically at full trigger the entire time until I hit LiPo cutoff. This surface is really easy on parts of the truck - no crashing, no jumping, no debris or dust - it does however work the drivetrain very hard from the inside out - the entire run with the trigger at full gas will really put the drivetrain through its paces.

Anyway, I have observed my rear diff a number of times and it is 'going gray' - I run white lithium grease in my diffs, and when I open the front it is as white as when I put it in there. The rear - with the Kraton crown - is graying up - which leads me to believe that the Senton input pinion and Kraton crown are slowly disintegrating each other.

So as to whether this is a good upgrade or not - only time will tell. I've gotten 19 packs with it thus far and will keep this thread posted as to how it holds up. To look at, both the Kraton crown and Senton input pinion seem good and the mesh is still excellent and tight - I hope to get 100 packs with it but we'll just have to wait and see. View attachment 9977 View attachment 9978 View attachment 9979
The question is. Can it handle 6s with mix matched gears?
 
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