[HELP Differential Durability

[Tommy Styrvoky]

I am wondering what sort of strain the newer/older differentials can take in terms of strain. I Think it is more likely that the 12z single bevel gears will fail prior to the differentials. I have plans for a Moc that could use up to 4 XL motors providing power through a single differential. I wonder if anyone else in the community has ever had a differential break under a very high torque load? If so I have a custom differential I can use in this application.

here's the custom differential design http://www.rebrickable.com/mocs/TommyStyrvoky/xl-differential

Edited December 15, 2015 by Tommy Styrvoky

[aeh5040]

I don't have any actual data, but I suspect that even 1 XL motor, ungeared, can break a 12 tooth bevel gear.

[Tommy Styrvoky]

I don't have any actual data, but I suspect that even 1 XL motor, ungeared, can break a 12 tooth bevel gear.

I have had that issue with older gray single bevel gears, but I think the newer ones are more durable, and I worry about the differential casing failing.

[Corvette3]

I have seen models with 4 XL Motors but no details on how diffs hold up.

[Saberwing40k]

Use the custom differential. The 3L differential have been known to slip under high torque in even single motor models. I don't know about breakage, but 1XL motor will shred single bevel gears and even axles if you aren't careful. Out of all the models I have seen that use four, most have each motor running a wheel, and not having them connected. The only exception I have seen with diffs is Sariel's red Hummer H1. Even then, that thing had portal axles, which would reduce the stress on the diffs. I don't remember if he had any breakage issues, but you could ask him. In the end, it all comes down to what your vehicle will be doing. If its a trial truck like vehicle, use a custom differential, and have gearing down between the diff and the wheels. If its a tank, Sariel built a Leopard 2 with four XL motors, and he had one at each drive sprocket, which is what I would recommend.

[Tommy Styrvoky]

Use the custom differential. The 3L differential have been known to slip under high torque in even single motor models. I don't know about breakage, but 1XL motor will shred single bevel gears and even axles if you aren't careful. Out of all the models I have seen that use four, most have each motor running a wheel, and not having them connected. The only exception I have seen with diffs is Sariel's red Hummer H1. Even then, that thing had portal axles, which would reduce the stress on the diffs. I don't remember if he had any breakage issues, but you could ask him. In the end, it all comes down to what your vehicle will be doing. If its a trial truck like vehicle, use a custom differential, and have gearing down between the diff and the wheels. If its a tank, Sariel built a Leopard 2 with four XL motors, and he had one at each drive sprocket, which is what I would recommend.

Here's my plan for the drivetrain (2-4XL motors)=>4 speed gearbox with new driving rings=>Subtractor with 2 differentials=>final drives

[AndyCW]

My experience is that the differentials will not break, the 3l diff may slip from the pinion gear. The problem comes from the bevel gears inside of the differential and how they are abused. Total forces imparted matter, but so does shock loading. I had a differential that if the power was applied slowly would stall out two 5292 motors before it broke anything, but if there were shock loads, like when there is wheel hop, the the gears could shatter. If you can keep the wheels one the ground, then they should last longer. The same holds true for regular automotive drive trains, wheel hop or chatter can break things just as much as total forces involved.

v/r

Andy

[doug72]

Problem I find with 3L wide differentials is the axles keep pulling out of the 12T thin bevel gears.

I haven't got space to use the out rigger arms that are normally used to stop this.

On the old version 4L wide you could use 1/2 bushes to stop this.

I need to mount a pair of wheels at minimum distance apart for a powered caster steering unit I am building.

Only option I see is to cut away the centre block on a 3L diff to allow 1/2 bushes to be used.

[TheNextLegoDesinger]

i had a problem with my 3l diffs that the bevel gear that conects to the power gets shredded a litlle bit, that even with 1 XL motor