Granite CNC Diff worth it?

[Prisma]

Hey everyone,

Yesterday I destroyed the rear diff gears in my V3 granite, running it on 3S. Now I've been thinking of upgrading a few parts and most importantly switching the rear diff with a CNC one. Do you think it's worth the extra $40? Or should I just keep reusing the stock plastic one over and over instead?

 

[islandlife]

From what ive read on here, the yolk is the critical part in the 3s rigs. But no personal experience

 

[Prisma]

From what ive read on here, the yolk is the critical part in the 3s rigs. But no personal experience

The yolk? That would be the issue if the diff strips during landings maybe? My strips because I press the throttle too hard

 

[pug]

The yolk? That would be the issue if the diff strips during landings maybe? My strips because I press the throttle too hard

Loosen your slipper to see if that helps. Tighten it to full with the wheels dragging then back it off 1 1/2 turns.

 

[morrjr71]

I recently put the ARRMA CNC steel complete diff modules in my Typhon 3s, but I only had time to run it enough to make sure everything was working properly. The CNC diff modules came from the factory with perfect gear mesh and are as smooth as glass. All I had to do was install them - no shimming required.

The Hot Racing yokes are supposed to prevent diff yoke deflection: this deflection can cause the pinion/ring gear mesh to vary under certain conditions, thereby damaging the gears. You might want to try this less expensive way to reduce gear issues before going all in on the CNC diff modules.

 

[SrC]

Just replace with another plastic one. I imagine the metal one will also wear out like my metal 6s rigs do anyway. $40 is expensive for sure. Replacing it will happen anyway. That's a subjective call. what is more practical for you. Metal will still wear out at some point.

I recently put the ARRMA CNC steel complete diff modules in my Typhon 3s, but I only had time to run it enough to make sure everything was working properly. The CNC diff modules came from the factory with perfect gear mesh and are as smooth as glass. All I had to do was install them - no shimming required.

The Hot Racing yokes are supposed to prevent diff yoke deflection: this deflection can cause the pinion/ring gear mesh to vary under certain conditions, thereby damaging the gears. You might want to try this less expensive way to reduce gear issues before going all in on the CNC diff modules.

+1

 

[Prisma]

Just replace with another plastic one. I imagine the metal one will also wear out like my metal 6s rigs do anyway. $40 is expensive for sure. Replacing it will happen anyway. That's a subjective call. what is more practical for you. Metal will still wear out at some point.

+1

Okay, gonna try another pair of plastic gears and get a new body for the money I've saved by doing that
Thanks for the advice!

 

[SrC]

+1
Consider Metal yokes first, if anything at all.

 

[MambaSenton]

Okay, gonna try another pair of plastic gears and get a new body for the money I've saved by doing that
Thanks for the advice!

Grab them at Jennysrc complete diff like 15$ I believe

 

[GRC]

The yolk? That would be the issue if the diff strips during landings maybe? My strips because I press the throttle too hard

All of the above suggestions are good. I also think rear diffs get stripped for 2 different reasons. 1) Being too aggressive with the throttle/brake 2) landing impact from jumps that throw the diff and input out of alignment. Both combined will of course strip the diffs as well.

1) First thing you should try is not landing jumps while on the throttle or brake. Let go of the throttle/brake just before landing. The wheels can drastically change spin speed upon landing. If you are on the throttle or brake, the differential will be engaged, and will resist the change in speed. This can strip the gears. So, land in neutral.

2) If you are stripping from being hard on the throttle rather than landing impact, loosening the slipper may help. I've never stripped a diff from jamming on the throttle. It may be because I keep my slipper 1.5 turns loose.

3) Next, I would try the Hot Racing aluminum differential yoke. It's much stiffer than the stock plastic yoke, so it prevents the differential and input gear from getting misaligned and stripping. I agree this probably helps mostly with landings, but it may also prevent the diff/input gear from misaligning from hard throttle changes.

4) I use the Hot Racing yoke in the rear. It definitely reduced stripping diffs from landing impact. But I jump pretty high, so I still managed to strip diffs. I added the 4s Center Brace to reduce chassis flex. So far so good, I have not stripped the rear diff since.

5) So far, I haven't needed the CNC metal diff and input gear. But from feedback in the forum, it sounds like it's a good solution to reduce stripping. I would think the CNC diff/input gear works best along with the Hot Racing aluminum yoke. This is obviously the most expensive option.

 

[Prisma]

I think rear diffs get stripped for 2 different reasons. 1) Being too aggressive with the throttle/brake 2) landing impact from jumps that make the diff and input gear flex. Both combined will of course strip the diffs as well.

1) First thing you should try is not landing jumps while on the throttle or brake. Let go of the throttle/brake just before landing. The wheels can drastically change spin speed upon landing. If you are on the throttle or brake, the differential will be engaged, and will resist the change in speed. This can strip the gears. So, land in neutral.

2) Next, I would try the Hot Racing aluminum differential yoke. It's much stiffer than the stock plastic yoke, so it prevents the differential and input gear from flexing against each other and stripping.

3) I use the Hot Racing yoke in the rear. It definitely reduced stripping diffs from landing impact. But I jump pretty high, so I still managed to strip diffs. I added the 4s Center Brace to reduce chassis flex. So far so good, I have not stripped the rear diff since.

4) So far, I haven't needed the CNC metal diff and input gear. But from feedback in the forum, it sounds like it's a good solution to reduce stripping. I would think the CNC diff/input gear works best along with the Hot Racing aluminum yoke. This is obviously the most expensive option.

Definitely gonna try getting the yokes then. I really wanted to get the center brace, but then I forgot and bought a pair of incompatible 3s shock towers, so I feel stupid right now.
Is there a way though to lower the damage dealt by using the throttle aggressively? It's always a worry of mine that I'll strip it by accelerating too quickly.

 

[pug]

Definitely gonna try getting the yokes then. I really wanted to get the center brace, but then I forgot and bought a pair of incompatible 3s shock towers, so I feel stupid right now.
Is there a way though to lower the damage dealt by using the throttle aggressively? It's always a worry of mine that I'll strip it by accelerating too quickly.

I slam the throttle all the time in my Typhon 3s, the diffs still look new after a year. Make sure your slipper is loose enough and you aren't landing on the throttle. And make sure the bearing on your input gear isn't damaged.

 

[GRC]

Definitely gonna try getting the yokes then. I really wanted to get the center brace, but then I forgot and bought a pair of incompatible 3s shock towers, so I feel stupid right now.
Is there a way though to lower the damage dealt by using the throttle aggressively? It's always a worry of mine that I'll strip it by accelerating too quickly.

All 3-4s shock towers are compatible with the center brace. I'm using one on my Granite, which uses the same shock towers as the Senton. You can check the Kraton 4s exploded view for the parts needed. https://www.arrma-rc.com/interactive-exploded-view/ARA102690

I edited my post to include loosening the slipper as a solution for being hard on the throttle.

 

[Prisma]

All 3-4s shock towers are compatible with the center brace. I'm using one on my Granite, which uses the same shock towers as the Senton. You can check the Kraton 4s exploded view for the parts needed. https://www.arrma-rc.com/interactive-exploded-view/ARA102690

I edited my post to include loosening the slipper as a solution for being hard on the throttle.

Good to hear! Although it's quite hard to tell which parts you need from the exploded view, so I'll have to do a bit of digging.
Thanks for all the advice though!

 

[StephenSchandelmayer]

I opted to remove the thought of stripping and did the metal diffs. Sure the metal goes bad sometimes on the 6s rigs but...that's 6s and much more weight. Get the metal diff in the 3s and you will probably never have to replace it, I tried all different levels on the slipper and what not and kept stripping plastic. And sure you can be smoother on the throttle and brake but what's the fun in that? Throw the metal on and fahgettaboutit is my opinion

 

[GRC]

This video description has a parts list for the center brace, as well as a good tip to secure the brace if you're not using 4s body posts.
(FYI: SWB vs LWB models use a different length center brace bar. Vorteks and Vendettas have some parts integrated into the shock tower and require fewer parts)

One little tip that's not in any of the videos I looked up. There are no instructions telling you how far down you should screw the front brace mount onto the rod, but if you look on the rod, there's a notched line that tells you when to stop.

 

[parcou]

Definitely gonna try getting the yokes then. I really wanted to get the center brace, but then I forgot and bought a pair of incompatible 3s shock towers, so I feel stupid right now.
Is there a way though to lower the damage dealt by using the throttle aggressively? It's always a worry of mine that I'll strip it by accelerating too quickly.

I was in your place some months ago. Do not land while on power....get the HR metal yokes to stop the flex and keep the stock parts. The yoke saved my plastic input gear to stop the flex make sure it is shimmed and meshed good....I do not jump or do send its so never was an issue landing on power.

Best of luck!

 

[Crunchy Gears]

If you're keeping the power system stock, there really isn't a need to upgrade to metal diffs. I got about 30 packs out of mine before the rear died.

They're dirt cheap on Jenny's for the stock ones and for plastic are very resilient as long as you let go of the throttle before you land