The Strongest Savage Diff Compilation.

[Jahay]

Ok Guys... i am about to do an entire rebuild of my diffs and even though i have GH Alloy bulks, my diff internals and bearings continue to fail sooner than i like.

A few things i want to touch on here...

Diff Case - It has come up that people want to get rid of the stock alloy diff case as it uses the 10x16x5mm bearing that seems to fail extremely quickly.
What are the alternatives that are able to work with the HPI BP Ring gear?

What i know so far, but any input would be better...

Forza flux diff case works (Proven here http://www.rc-monster.com/forum/showthread.php?t=29094) but i do not like the idea of using a plastic diff case with a heavy MT application and huge brushless power. Flex in the case will occur eventually and cause premature wear of the spider gears. But i am following that post to see how it goes.
-This works because the stock savage spider gears drop right in and the BP Ring gear bolts on.

Another option was the HELLFIRE DIFF CUP... BUT this requires more work. Yes it uses the 8x16x5mm bearing but the internals of the cup are not the same as a stock savage cup.
Up to 32 shims are required for getting all the internals shimmed correctly... But the BP RING Gear does fit fine.

Spider Gears - We all know that the savage spider diffs are OK and are hit and miss... some complain that they alway wreck them and others are ok. Bit some people have talked about these http://www.hpiracing.co.uk/piw.php?partNo=101142 having better thicker surface area and result in a stronger better mesh. Only problem is that it can be a tight fit without 1 or 2 alloy Diff gaskets from a hellfire http://www.hpiracing.co.uk/piw.php?partNo=86599

Diff Case Screws - When ever i need to get into my diff, i always seem to shred these rubbish stock screws.
What HEX HEAD screws would be ideal... anyone know?

THANKS

JOSH

[_dV]

Well, for starters I don't know what I'm doing wrong (or right). I have only ever run the stock Flux composite bulk and stock bulletproof diffs without any bearing or gear breakages. I've always run heavy silicon fluid in them (50K-100K) and haven't used any really heavy wheels or larger\longer can motors than stock, so that might have something to do with it.

Diff Case - I have a Vorza center diff and the case is a composite but felt very stiff. If these cases work it would be great as it also avoids loctite\silicon fluid in thread issues.
An alternative to a different case might be to just use a high quality ceramic bearing for the 10x16x5.

Spider Gears - again have never damaged one but would be nice to have a stronger option. Haven't heard of any other options.

Diff Case Screws - Hex heads are heaps better than stock. Have been using some that were in my Tony Screws kit.
Stock screw (M3x15mm) http://www3.towerhobbies.com/cgi-bin...529+&search=Go
HPI hex screw(M3x15mm) http://www3.towerhobbies.com/cgi-bin...?&I=LXMAB8&P=7
That said you can still damage the head and it would be great if somehow a larger screw could be used but that's unlikely. With the plastic case I have wondered if I could drill right through the case and put a lock nut on the one end. Probably not enough space in the bulkhead for that though.

What I would really like are harder outdrives. They are what wear on me the most where the dogbone pin rubs.

[lincpimp]

Well, I have run a few different savage diff setups.

Old 21/25 savages had 2 spider gears, you could upgrade them to 4 spiders with a hpi kit. Composite cups usually wore out where the cross shafts slipped in. Not good enough for regular mt wheels/tires and a feigao xl.

So I went to the hpi al diff cups. Curred the cross shaft issue as the shafts were in al tracks instead of plastic. However the ring and pinions started to break.So I tried shimming them, seemed to help but the rear ring and pinion went again. Blamed the flexible stock plastic bulks for that. Never had bearing issues but I have a feeling I would had the diffs held up better.

I do have a set of gh bulks with bulletproof gears in them. Have not run them yet, but they are said to be the best out there.

I do agree that heavy diff fluid should help the spider gears. Landing on one tire with the throttle wide open transmits alot of shock to the spiders.

Wonder if the hot bodies hardened spiders for the lsp would fit in the savvy diff cups? I have a set somewhere, will have to try. I know they do not fit lst diffs, but the cups are smaller on those.

[rhylsadar]

imo the "evolution" of the savage diffs since the legendary savage 21 in 2001 (? or was it 2002) showed up went through several steps.

- the 2 spider diffs were upgraded to 4 spiders
- after that the little sliding blocs were introduced to prevent the cross shafts to work into the plastic cup. today these sliding blocs are usual in traxxas and hpi diffs in their monster trucks. this could be done with the plastic or the aluminium cups.
- the hpi cup was replaced with the kyosho part IF103 (uses a 8x16mm on a steel ring)
- the 43T gear was modified to accept 8x16mm bearings.
- later the outer-bearing modification was done to further strengthen the diffs and reduce the load on the inner bearings.
- several aluminium cups were offered in the tuning market since nearly the beginning
- the 43T bevel gear and 13T were hardened and called "heavy duty" etc etc
- with the savage flux the bulled proof diffs came with the 29T and 9T gears.
- of course various combos of the different mods were done.

bye
rhylsadar


here some old pics of some mods done to savage diffs.

a GH alum. diff cup


here a maximizer alum diff cup, the small sliding blocks, and prepared diffshafts to accept the outer bearings


prepared diffshafts


bevel gear with 8x16mm bearing


IF103 diff cup with 8x16mm bearing


diff with the inner and outer bearings


prepared bulk for the outer bearing, of course you can do this with alum. bulks

[JasonB]

Interesting history rhylsadar. Never would have thought to turn down the diff shafts . . . I like it!

The only problem with the existing savage flux diff offerings is the stupid 10x16 bearing. The ultimate diff would be the bullet proof ring gear combined with an aluminum cup that has a steel endcap that accepts the 8x16 bearing. All they have to do is copy the CEN diff case idea. Why on earth hasn't someone started mass produceing a product like this? It would sell!!!

BTW, I don't think an all aluminum cup turned down to accept the 8x16 would work any better than what we have now because the thin wall would quickly give in to stress fracture.

I think the Hot Bodies or Kyosho plastic diff case with steel ring is better than the aluminum junk we have to settle for, but I know they can do better. Just blows my mind that they haven't yet.

[_dV]

Informative post rhylsadar. Thanks for taking the time.

There is definitely a need for a decent diff cup. There was a guy starting to make titanium parts on Savage Central. I was trying to get him to make some but he hasn't posted in a while.

If only there was a composite\plastic cup with 8x16 steel bearing end cap that accepted the sliding blocks for the internals.

[Jahay]

thanks for posting that thread!!!

i love the idea of all these extra bearings to help take the strains of these brushless systems!!!

_DV i knew that guy on savcentral was never going to produce... they rarely do after they realise how little profit there is in it for them...

Jason... do you really think the Hot Bodies or Kyosho plastic diff case with steel ring is better? does it accept the BP ring gear? and i also hears the spiuder and bevel gears are a little tougher too!!!
you got any part no. or links to them? thanks

[rhylsadar]

hi

i have serveral different modded diffs in my savages.
one of the last things i have done is the 9T/29T bullet proof bevels combined with the kyosho IF103 plastic diff cup with the steel ring and the little sliding blocs. so there are now 8x16mm bearings on both sides.

i guess the outer bearing mod is only possible with the old non-x-version of bulks and diff housings.

the cen diff mod seems to be a very nice option too.

bye
rhylsadar

[Jahay]

Yes i am running the BP Gears too... Definitely cant beat them for strength.

I am going to look into the kyosho diff cup... i really like the idea of the 8x16 bearing which continues to fail on me! Are you using the stock savage spider gears and sliding blocks with it?

I was going to buy these internal gears
http://cgi.ebay.co.uk/ws/eBayISAPI.d...T#ht_500wt_764

These gears are meant to be a little thicker and stronger than the stock savage internals... Do you think they would work?

Thanks for the help bud

edit..
is this the diff case that uses the 8x16 bearing and has the steel ring around it?
http://cgi.ebay.co.uk/KYOSHO-IF103-I...#ht_1073wt_750

[simplechamp]

You might want to check on those diff gears. I know HotBodies also has HBC8101-1 that are labeled as hardened steel, while the HBC8101 are just labeled as steel. They could be the same, but I would get the -1 version just to be safe.

http://www.hbeurope.com/piw.php?part...8101-1&lang=en

I am using these gears in my Jammin on-road diffs, but haven't had a chance to test them yet. They seem like they should be very solid though.

If you are thinking of using Kyosho 777 diff case, you can also use Jammin cases, which are the same as Hot Bodies too. Nova RC makes alloy cups, which I also have but haven't tested yet. Innovative RC in the UK also makes alloy Hot Bodies cups.

[JasonB]

Originally Posted by Jahay

thanks for posting that thread!!!

Jason... do you really think the Hot Bodies or Kyosho plastic diff case with steel ring is better? does it accept the BP ring gear? and i also hears the spiuder and bevel gears are a little tougher too!!!
you got any part no. or links to them? thanks

Yes I do, and Yes it does; time will tell if it really is a tougher combo. I don't have the Kyosho diff case, but from the pictures it appears to be identical to the Hot Bodies one I'm using now. I've read that the Hot Bodies spider gears are tougher too, but I'm using stock Flux gears for now until I use up my spares. It's all in my post that you linked to at the top of this thread. (link)

[JasonB]

Originally Posted by rhylsadar

hi

i have serveral different modded diffs in my savages.
one of the last things i have done is the 9T/29T bullet proof bevels combined with the kyosho IF103 plastic diff cup with the steel ring and the little sliding blocs. so there are now 8x16mm bearings on both sides.

How did you get the sliding blocks in there? Pics??

[rhylsadar]

hi

the IF103 cup is available e.g. at amain.
those sliding blocs are smaller than those in the hpi aluminium cup. you can see them in the second pic above. you need to modify the cross pins at the ends and produce some small blocs on your own.

i have only found a pic with the blue cup.



bye
rhylsadar

[Jahay]

These are the alloy cases being sold by IRC
http://www.innovative-rc.com/lightni...ver-p-209.html

They have the 8mm bearing capabilities... but do you think these would :

Firstly accept the BP Ring gear..

Secondly accept the HB Internal gears? http://www.hbeurope.com/piw.php?part...8101-1&lang=en

Thirdly accept the stock savage blocks? or would another block be required?


If yes is the answer then this is the alloy case we have all been waiting for?

[JasonB]

Since the IRC cup is made for the Lightning Stadium and we now know the stock Lightning Stadium cup fits the Flux, it's a safe bet that it will fit.

Problem though is that aluminum isn't very strong when you thin it down, and the cup needs to be quite thin to accept the 8x10 bearing. The issue is further compounded by the diff shaft wallering out the cup sleeve from the inside until it becomes brittle enough to snap; this has been my experience with a turned down stock cup. With a steel sleeve this problem doesn't exist. Just my opinion.