Felony Did the GP5 rear diff /Kraton rear hub conversion so I can run 42/100 Hoons all around

[Engineer]

I'm sure Arrma's supply chain will soon catch up, but the weather up here in Northeast Ohio will turn cold and wintery sooner than later and I don't feel like waiting till October/November when 53/107 Hoons show up. I saw this video posted here:

(

which looked like a great solution and so I picked up the Kraton parts:

and a GP5 differential from JRC:

Took out the diff and checked it. A little low on fluid - so after reshimming it with Mugen shims and topping off the fluid, it was ready to go:

Photo of the Kraton hub carrier installed:

Once you put the body on, everything has a good look to it:

I'll probably keep it this way for the foreseeable future and this will also let me run GRP tires on it as well.

 

[odier]

Nice work. Thanks for the tips and pics.

 

[MFM]

@Ivgot2manyRC here ya go bud.

 

[Yas]

Great idea... I didn't think to use Kraton hubs for the offset. In case anyone else wanted to do this conversion too, the only parts needed for the offset are:

AR330404 - Kraton hubs
AR310591 - Kraton axles

The Felony's rear 17mm hexes and pins are the same as the Kraton's

 

[Engineer]

Great idea... I didn't think to use Kraton hubs for the offset. In case anyone else wanted to do this conversion too, the only parts needed for the offset are:

AR330404 - Kraton hubs
AR310591 - Kraton axles

The Felony's rear 17mm hexes and pins are the same as the Kraton's

Thanks! Although I didn't come up with the idea (see the video). The hexes are a little short (also noted in the video).

Coincidentally I needed a set of Kraton front hubs so I just purchased a whole set of front/rear hubs, hexes and axles from Jenny's and took the rears for the Felony.

 

[Yas]

Thanks! Although I didn't come up with the idea (see the video). The hexes are a little short (also noted in the video).

Coincidentally I needed a set of Kraton front hubs so I just purchased a whole set of front/rear hubs, hexes and axles from Jenny's and took the rears for the Felony.

I'm surprised the Felony's rear hexes fit tight on the Kraton axles - I've just triple checked and they share the same wheel hex AR310484

Maybe they've listed one of them wrong in the part explosions ?

 

[Pioupiou2607]

Bonne c'est bien des pièces du Kraton 8s
Je ne trouve pas cette référence AR310591 - Essieux

 

[Engineer]

Bonne c'est bien des pièces du Kraton 8s
Je ne trouve pas cette référence AR310591 - Essieux

I think it’s parts from a Kraton 6s and not 8s.

here is the link to that part number:https://www.arrma-rc.com/part/AR310591

 

[Pioupiou2607]

[QUOTE = "Ingénieur, poste: 399508, membre: 17931"]
Je pense que cela fait partie d'un Kraton 6 et non d'un 8.

voici le lien vers ce numéro de pièce: https://www.arrma-rc.com/part/AR310591
[/CITATION]

merci

 

[Stygian]

I did some mathing *smoke from ears* but if you do nothing except swap the front and rear diff in the felony, you get a gear ratio of 3, exactly... On both front and rear diffs. That's keeping the front input gear in the front and rear input gear in rear.

Tested, matched, tested it again, then ran it like I stole it and all is perfect, I'm able to run the fronts 42/100s on all four corners with out issues. As for offset you can also nab the m2c 10mm offset hub extensions for that difference too. Instead of a Kraton hub conversion. It's a much easier swap to and from as tire availability permits.

 

[luis41510]

I did some mathing *smoke from ears* but if you do nothing except swap the front and rear diff in the felony, you get a gear ratio of 3, exactly... On both front and rear diffs. That's keeping the front input gear in the front and rear input gear in rear.

Tested, matched, tested it again, then ran it like I stole it and all is perfect, I'm able to run the fronts 42/100s on all four corners with out issues. As for offset you can also nab the m2c 10mm offset hub extensions for that difference too. Instead of a Kraton hub conversion. It's a much easier swap to and from as tire availability permits.

What gears do I buy ? I want to switch my tires as well?

 

[luis41510]

I'm surprised the Felony's rear hexes fit tight on the Kraton axles - I've just triple checked and they share the same wheel hex AR310484

Maybe they've listed one of them wrong in the part explosions ?

Do they not fit?

 

[SrC]

I did some mathing *smoke from ears* but if you do nothing except swap the front and rear diff in the felony, you get a gear ratio of 3, exactly... On both front and rear diffs. That's keeping the front input gear in the front and rear input gear in rear.

Tested, matched, tested it again, then ran it like I stole it and all is perfect, I'm able to run the fronts 42/100s on all four corners with out issues. As for offset you can also nab the m2c 10mm offset hub extensions for that difference too. Instead of a Kraton hub conversion. It's a much easier swap to and from as tire availability permits.

On paper, the MATH does work. Like you state But GP5 and GP6 gear sets ( input and ring) do not match. I suspect the gear pitches are different?
But if it works for you let us know how the gear sets are wearing.

 

[Yas]

On paper, the MATH does work. Like you state But GP5 and GP6 gear sets ( input and ring) do not match. I suspect the gear pitches are different?
But if it works for you let us know how the gear sets are wearing.

The pitches are the same as far as I'm aware. I've tried it myself and GP5 and GP6 gears mesh perfectly. Due to fitting smaller gears together in one diff and larger gears together in the other, they do need shimming completely differently

 

[flynlw]

I did some mathing *smoke from ears* but if you do nothing except swap the front and rear diff in the felony, you get a gear ratio of 3, exactly... On both front and rear diffs. That's keeping the front input gear in the front and rear input gear in rear.

Tested, matched, tested it again, then ran it like I stole it and all is perfect, I'm able to run the fronts 42/100s on all four corners with out issues. As for offset you can also nab the m2c 10mm offset hub extensions for that difference too. Instead of a Kraton hub conversion. It's a much easier swap to and from as tire availability permits.

Hi there, I’m new to the felony world, and have received conflicting information about this diff swap. Are you still running it this way? Are there any issues with gears meshing? What tires are you running? Thanks

 

[SrC]

The pitches are the same as far as I'm aware. I've tried it myself and GP5 and GP6 gears mesh perfectly. Due to fitting smaller gears together in one diff and larger gears together in the other, they do need shimming completely differently

Way much shimming needed, from what I gather.
If you are good with a 3:1 ratio(Fr-Rr) and gear mesh works... great. Gear accordingly. Nothing to buy.
2.8:1 is the GP5 setup for the Infr.
I am not convinced just yet. I can be stubborn. GP5/6 gear published specs don't indicate any interchangeability. Why I question it..
I recently emailed Arrma regarding this question. FWIW.

 

[SrC]

I recently confirmed that simply swapping the Felony diff main gears (GP5's to rear/GP6's to front) is not correct to do. The math may prove it on paper ratio wise, however, functionally the GP5 main gears are not interchangeable with GP6 input gears. And conversely.

If you want to run 42/100mm Hoons at the rear on a Fel., you need to have a GP5 gear set( input gear and main gear) at the rear.
This becomes an Infraction V2 setup. (2.8:1 ratio's at both F/R diffs)

The above was confirmed with Arrma Tech. Supp. (N. America)

 

[Greywolf74]

So before reading this and being new to Arrma when someone said buy the gp5 diff to replace the gp6 diff I thought they meant a felony gp5 diff like the one thats in the front. Everyone here seems to be saying buy the infraction gp5 diff. is there a difference? Did I buy the wrong one?

 

[Yas]

So before reading this and being new to Arrma when someone said buy the gp5 diff to replace the gp6 diff I thought they meant a felony gp5 diff like the one thats in the front. Everyone here seems to be saying buy the infraction gp5 diff. is there a difference? Did I buy the wrong one?

Don't worry, you did buy the right one. The GP5 diff set is in the Felony front, and both front and rear in the Infraction

Just make sure you use the GP5 pinion with it

 

[Greywolf74]

Don't worry, you did buy the right one. The GP5 diff set is in the Felony front, and both front and rear in the Infraction

Just make sure you use the GP5 pinion with it

Thank you!