Are the portal input/output gears a big weakness?

[Spence]

Hi guys, sorry for all the questions. I was just curious if the portal input and or output gears are significantly weak? I was watching a video from rcreview on his trx4 how he broke his and now I'm all worried.

I know a lot of these rc gears are powdered metallurgy based steel.. I can see yes that traxxas makes a front shaft and gear upgrade as well as a rear...

I know these trx4's can take 6s brushless out of the box as kevin talbot has shown...

I'm not planning to abuse mine, just going to be setup with my axe 2300kv on 3s for crawler duty...

I guess there are KYX and devils rc rear portal input gear upgrades...



Thanks
-Spence

 

[Schs2013]

Have not broke one yet. Build the kit and figure out what upgrades you need as you break things.


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[kr0wl402]

I got the 2800kv axe r2 system in my Sport and it holds up fine. I do both a bit of mudding and trailbashing.

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[Ninomaniac]

One of the very few weak points. I chipped a set in one of the rear portals. I am not gentle with my TRX. Anything Axial would probably be f%&'ed up by now if I drove it like I do my TRX4. Nothing to worry about.

 

[Spence]

Thanks guys for your help..

So you guys are saying basically don't rush out and pre-buy the upgrade gears? I see yeah racing makes a portal output gear (lower portal gear) and traxxas does make front and rear portal input gears along with the driveshafts, in addition to kyx and devil rc from locked up rc...

But at the same time I'm extremely tempted to get the traxxas front and rear chromoly ones.

I guess the issue arises when the vehicle lands when under power or bounces or wheel hops under a high load, as the input gear is a hardened steel sintered metal it will tend to be brittle... But additionally, sintered steel parts will never be as good as a quality hobbed machined gear..

Since the portal output gear is made of the same sintered material, I'm curious why it doesn't break typically lol..

 

[smc-93]

Thanks guys for your help..

So you guys are saying basically don't rush out and pre-buy the upgrade gears? I see yeah racing makes a portal output gear (lower portal gear) and traxxas does make front and rear portal input gears along with the driveshafts, in addition to kyx and devil rc from locked up rc...

But at the same time I'm extremely tempted to get the traxxas front and rear chromoly ones.

I guess the issue arises when the vehicle lands when under power or bounces or wheel hops under a high load, as the input gear is a hardened steel sintered metal it will tend to be brittle... But additionally, sintered steel parts will never be as good as a quality hobbed machined gear..

Since the portal output gear is made of the same sintered material, I'm curious why it doesn't break typically lol..

When my TRX4 was still on portals I never hade issues with the portal gears. I wasn't exactly gentle on it and the only "damage" was the polished surfaces where the gears meshed.

IMO, the only reason to change the portal gears/shafts is if you want wider output shafts. Or if you managed to break them some how.

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[ScaleLifeNewbie]

Thanks guys for your help..

So you guys are saying basically don't rush out and pre-buy the upgrade gears?

Yes. When I build a kit I never buy anything extra except the basic necessities(motor, tires, etc.)

Drive it until something breaks and then replace it. It's not only cheaper that way but also better than throwing a bunch of brass on and it drive like crap for example.

 

[Ninomaniac]

A couple of us bash our TRX4s. Think demolition derby with jumps. What breaks is mostly plastic sticky-out parts (e.g. panhard mounts on both sides). But even that is unlikely to happen if crawling or trailing around. We bend a shock shaft or break a bumper mount now and then, but like I said, they get crashed A LOT.

So just build it and don't worry. It's definitely the most durable kit I or any of the people I know ever had.

 

[AnimalHippie]

Don’t worry about those gears. Pretty much have to be doing something you shouldn’t have been doing to break them. I’ve twisted my axles all up under my truck, tires tightly wadded up underneath the edge of a rock too many times. Never broke one. Probably should have broken something, but didn't. Panhard mounts are the only weakness I have found under crawling conditions. Didn't break. Just bends under pressure. Other then the stock electronics.

I push my truck pretty hard. Still has stock driveshafts, gears, axle internals other then the LockedUp RC locker I put in the front. I would spend the $$ somewhere else on your rig. Good luck Brother!!!


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[meatmonkey]

I've broken a couple cvds, busted up the ball, barrel, and pin. Even then the upper portal gear survived. Minimal distortion to the pin holes, so just a new inner with barrel and sleeve and alls well.

They don't break easily, and both of my failure examples were well worn. Replacing the pins sooner may have prevented the barrel/inner shaft failure.

I'd be spending money on a decent servo and esc well before worrying about drivetrain parts. Mechanically the trucks a tank, but the electronics are it's weak point.

 

[CrazyAce211]

These trucks make Tonkas look like glass. I mainly run mine as a basher. 3-4 foot jumps with bad landings and all. I've yet to break a part.... its honestly kind of annoying. I dont know what to upgrade until I break something.