Granite Granite trouble..

[Yonic]

Locking the diff should put MORE stress on the outdrives, not less.

With open diff each side can get between 0-50% of power, with locked diff it's 50-100%.

 

[suchtragedy]

Locking the diff should put MORE stress on the outdrives, not less.

With open diff each side can get between 0-50% of power, with locked diff it's 50-100%.

You're actually right I got my understanding or how torque works in locked vs open wrong. When it broke my nephew hit a jump and kept the throttle pegged at 100% so while in the air the wheel speed jumped up as fast as that motor could go with zero load and when it landed the wheel that hit the ground first took all that energy and the wheel taking a jolt when resistance (friction force from the ground) was applied and that energy was enough to snap the weakest part of the drivetrain. However same scenario but with the diff locked it would still be the same torque force hitting that wheel, not 50%. Since the rotation force is still the same as what occurred with the open diff the only difference a locked diff would be the wheel speed of the wheel still in the air would slow at the same rate. So in theory the locked diff would probably have broken on both sides and not just 1 side. So the only thing that's different is locked has a little bit better straight line traction but turns will be worse and car will be prone to traction issues and will drift/spin out and have worse tire wear.

So yeah I expect I will explode another diff shaft if I take a hit like the one that broke it the first time but I'm going to stick with it for now and maybe go brushless and make the voltage a top speed truck with a different set of tires maybe, or replace once it explodes again -- whichever comes first.

 

[Yonic]

With locked diff the back end will slide on even the slightest turns, it will be uncontrollable.

With 4x4 you can do this and make every turn into a power slide (similar to how the previous version of the Losi Baja Rey drove with locked rear diff), but with 2wd you won't have that, it'll just spin on every simple turn.

 

[jondilly1974]

With locked diff the back end will slide on even the slightest turns, it will be uncontrollable.

With 4x4 you can do this and make every turn into a power slide (similar to how the previous version of the Losi Baja Rey drove with locked rear diff), but with 2wd you won't have that, it'll just spin on every simple turn.

I’ve found that under power with a locked rear diff it will lift the front wheels off the ground and understeer greatly. At least with my K4S this is the case with 100k in both diffs.

 

[Yonic]

100k is far from being locked.

 

[jondilly1974]

100k is far from being locked.

It’s considerably more locked than the 7K stock fluid in a 4S truck ??‍

 

[Bennyboy2]

I run the 15T 540 arrma mega motor with 19T pinion and it's pretty quick on 2s but not to the point it's ridiculously over powered. I think you'd be happy with that.

I installed all new bearings all around and also put the new 15T motor in as well. When I reassembled however the mesh with the 16T pinion and the plastic spur gear seems so tight. When I powered up the car it seems like a grinding of the tight mesh and unfortunately cannot adjust at all. Wondered if you had any issue with that.
On another item while replacing bearings I was wondering if and where to add any grease on the internal diff and idler. I just wiped out a little of the real dirty grease and put it all together. Sounds fine when I roll the truck manually but with power there is def a tightness sound

 

[suchtragedy]

I installed all new bearings all around and also put the new 15T motor in as well. When I reassembled however the mesh with the 16T pinion and the plastic spur gear seems so tight. When I powered up the car it seems like a grinding of the tight mesh and unfortunately cannot adjust at all. Wondered if you had any issue with that.
On another item while replacing bearings I was wondering if and where to add any grease on the internal diff and idler. I just wiped out a little of the real dirty grease and put it all together. Sounds fine when I roll the truck manually but with power there is def a tightness sound

When I put in the 16T stock pinion it seemed tight to me as well. The 19T seems to have a better fit. Maybe try the 15T with the 16T mounting holes and see how that fits?

 

[Bennyboy2]

You know what’s funny I bought the 15t upgraded motor and yesterday horizon emailed me and said my replacement stock motor is in the mail. I just gonna go back to stock for now because I would never want to downgrade car for motor replacement?. Son just turned 5 today so he doesn’t really need an upgrade yet. That was just my thought if I buying something. Thanks for reply.

 

[Bennyboy2]

I got mine all apart switched all bearings out and horizon sent me a stock motor. I just saving the 15t one. I noticed my motor mount starting to crack by screw holes. When I got all back together almost has a small clicking sound when running. Rides ok just lil something extra going on. Not sure what that is but next time I need rear apart I will have to replace chassis

 

[suchtragedy]

I got mine all apart switched all bearings out and horizon sent me a stock motor. I just saving the 15t one. I noticed my motor mount starting to crack by screw holes. When I got all back together almost has a small clicking sound when running. Rides ok just lil something extra going on. Not sure what that is but next time I need rear apart I will have to replace chassis

I use an electric screwdriver most of the time and I found that the voltage screw points seem to crack pretty easily so I usually finish tightening down by hand. Sounds like that crack adds just enough play in the gear mesh to cause issues. I wish the motor mount was it's own mounting plate attached to the chassis and not actually part of the chassis itself. Seems stupid to need to replace an entire chassis for one single part that has nothing to do with the rest of the car and how it drives.

Good luck dude.