I am using the IRC Hot Bodies Lightning Stadium alloy cups. Nova RC also makes an alloy cup, any Kyosho 777/HotBodies/Jammin cup should work, they are the same size.

They DO NOT use a sliding block however, just the slots in the walls of the diff cup.

I am using the HotBodies hardened steel internals, 8101-1. I do not know if the SHD Savage outdrive cups will fit, they are listed as 9x11x34 but I don't know exactly what those dimensions are for. The outdrives used by the IRC cups (and most other 1/8 outdrives) are 6mm shaft.

I hope I have not been confusing everyone, but my diffs I built up are not in a Savage, they are in Jammin bulkheads. I just posted in the thread to let you guys know about the IRC diff cups and the hardened internals, and that they would work together.

Just out of curiousity... is it worth buying Titanium cross shafts???http://www.hpiracing.co.uk/product/ED070030,

are the stock ones made from steel???

I know Kyosho also makes titanium cross-shafts that will work with the Kyosho/HotBodies/Jammin cases and gears we've been talking about.

I'm not sure if you will see a noticeable difference in titanium over steel, and I think the titanium ones are pretty expensive. I am actually using the Ofna aluminum cross-shafts and they seem to hold up fine. Again, this is in a 1/8 buggy, so the Savage will be tougher on them, but I think steel or aluminum is fine (probably steel for the Savage?).

EDIT: Here are the Kyosho titanium shafts, at $15/pair you're looking at $45 for a set of 3 diffs. I'd just go for steel: http://www.amainhobbies.com/product_...el-Shaft-Set-2

thanks for the input champ... so im guessing i cannot use the stock steel cross shafts from the savage in the IRC Hot Bodies Lightning Stadium alloy cups?

Would i have to use the kyosho steel shafts? does this mean that they eliminate the need for the sliding blocks that are used in the stock savage diff cases???

THANKS
slowly getting closer, to understanding everything that is needed.

Why would you think the savage cross shafts wouldn't fit in the HB alloy cups when we already know they fit in the HB plastic cups?:neutral:

No; the savage sliding blocks cannot be used in the HB cups.

The Savage shafts should work fine, the cups are designed differently so no sliding blocks are needed. Here is the IRC Lightning Stadium cup with HotBodies hardened steel gears and regular steel shafts. You can see the slots that the cross-shafts fit into.

The Savage ring gear should be able to work OK with this diff setup. If the internals feel too loose you can add shims behind the gears. If the internals feel too tight try using 2 diff gaskets instead of 1 to space things out.

EDIT: I added another pic, this is what I call my "diff first-aid kit". Not a bad idea to put one of these together and throw it in your toolbox.

Champ, thanks for the info and pics...... clearing up a few things defintiely.
Loving your diff aid kit... i have a crazy number of diff bits, but its all in a greasy mess... i should really clean it all up.

ANYWAY LAST QUESTION...

It does make it easier that there are no sliding blocks.. but does that mean the cross shafts slide in perfectly into diff cup spaces without any side ways movement?
I just am so confused as to why they desinged the savage cup to use blocks? do you feel blocks to a better job of holding everything in place and prevents unwanted horizontal and vertical movement?

Im going to buy the alloy cups now. Im sure the BP diff screw holes will line up.

Not sure on the exact purpose of the sliding blocks, or the benefits of them. If I had to guess I'd say they are to stiffen up the plastic cup, or keep the cross-shafts from digging into the plastic cup? Most 1/8 diffs don't use sliding blocks, the Savage and few other vehicles that do are actually the minority. And with an alloy cup it's one solid piece of metal, so no worry about flexing anyway.

There is a tiny bit of play between the cross-shafts and slots they go into, but there has to be a little bit to be able to slide them in and out and let them rotate. The walls of the cup and 2 larger gears are mainly what keep the 4 small gears in place. The cross-shafts are to keep them on-axis so the mesh stays right. At least that's how I see it.

Awesome! Thanks for the quick response.

Im ordering the IRC Lightning cups now... Ordered the HB Hardened internals and some more diff gaskets just in case...
I was considering getting the alloy diff gaskets from the hellfire... JUST IN CASE i need to create a little more space, the alloy gaskets would help pull the ring gear out a little... or otherwise ill just shim the large side gears into the spiders if there is too much play... (i doubt it though as these HB Internals are meant to be thicker than the stock savage gears) Only can wait and see...

THANKS FOR YOUR HELP AGAIN CHAMP!!!!!! asset to RCM!

Love the diff kit simplechamp!

Jason... it said in my previous message before you edited it that you want to see a "naked pic of the bearing side of the HB alloy diff cup?

I mind having a little look to get a rough idea...just in case it looks too small to accomodate a flux axle...

Do you have one champ?

If I were you, I would get the nova cup. Dimension wise, they are the same as the IRC ones. But in terms of material, nova is better since they use 7075 aluminum and IRC ones are 6082. 7075 is superior that the 6082. And I was told that the anodize on the IRC is not hard coated anodize, just normal ones, so it can help abit but not much.

Yes that may be true... but i have heard that people who have used the nova cup, needed 18shims per cup to make sure the internals do not move around???

Ok found the pics... But i dont know why they shim the cup.. Is it because they are using the wrong spider internals? Ar the internals from the savage being used instead of the larger Hotbodies hardened gears?

These are the shims required
https://store.vgracing.com/robitroni...10x0-15mm.html

Well here is a guy who used the nova cup... he kept stripping internals until he shimmed behind th bevel gears... here are the pics.

When its finished you want the top gear flush with the diff...
http://www.hpisavageforum.com/galler...5/DSC_0137.jpg

You shim the spiders in to get the proper mesh
these two showing 8 shims ....
http://www.hpisavageforum.com/galler...5/DSC_0134.jpg


All 16 shims + the two for the sun gears ..
http://www.hpisavageforum.com/galler...5/DSC_0138.jpg

IIRC, I read about this guy on hpisavageforum. He was using hellfire cup with Savage internal gears. Thats why he needs all the shimmings. The hot bodies internals should fit the nova cup (for LSP) w/o any shimmings.