Broken Portals

[MeanTT]

So I finally got my scale Unimog CFX-W mostly done. It is running a 23T pinion, 3500 KV HH motor and it has a bunch of extra weight. I’ve made a steel subframe and it runs a roll cage and hardbody body. I also run very heave 2.2 wheels with small 2.2 tires. I also run bearings instead of bushings.

My portal just blew up on its maiden battery after full assemble. It was climbing over a small incline. There was a mild hop and boom- gears blew up.

I couldn’t find any upgraded parts only replacements.

Have others had this problem? I hate to think that the portal design has a flaw after I spent 3 months building the platform.

Thanks!

[Teng]

As far as I know MST is lack of option parts, I would humble to suggest you to lower your truck’s weight and maybe lower kv motor would also help. We all know we like speed and fast acceleration and all these could broke a scale crawler parts easily. Cheers

P/s, lower your gear ratio also would help since you’re using 2.2

[MeanTT]

Originally Posted by Teng

As far as I know MST is lack of option parts, I would humble to suggest you to lower your truck’s weight and maybe lower kv motor would also help. We all know we like speed and fast acceleration and all these could broke a scale crawler parts easily. Cheers

P/s, lower your gear ratio also would help since you’re using 2.2

Yeah, I agree weight is a contributing factor, but 15 minutes is still 15 minutes! I was hopeful that someone had come up with something. The 2.2’s are about 4.8 diameter as they are RC4WD Baja MTZ. After hours learning how to braze and 20 hours weathering the rig and painting the body letting go is a hard ask.

Crap, this whole build was based on portal axles.

P.S. how are folks hosting pics these days (now that photo bucket is dead) so I can show the carnage and the rig?

[MeanTT]

Originally Posted by Teng

You can use tapatalk it is free, just need to download into your smart phone or tab like iPad or Samsung galaxy and you’re good to go.


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Here is a pic I also threw up in another thread. Pics of the rig in its current stage of finish below.





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[Teng]

wow, looks like a real truck. Amazing. As we earlier discuss it seems the weight really contributed to broken your parts. Need diet already


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[THX_138]

Originally Posted by Teng

wow, looks like a real truck. Amazing. As we earlier discuss it seems the weight really contributed to broken your parts. Need diet already


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Weight????

It appears there's not much there for weight. If the portals can't handle that little bit, not sure what they could.
I'd say it was just a poorly cast part, but who knows.

It's just part of the hobby, break em and fix em over and over. Just stinks when it's minutes into a maiden voyage.
Like looking MOG

[Teng]

Ya, you are correct too. This truck need heavy duty CNC gear set. But unfortunately the MST is lack of after market support.


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[MeanTT]

Originally Posted by THX_138

Weight????

It appears there's not much there for weight. If the portals can't handle that little bit, not sure what they could.
I'd say it was just a poorly cast part, but who knows.

It's just part of the hobby, break em and fix em over and over. Just stinks when it's minutes into a maiden voyage.
Like looking MOG

Actually, there is a good amount of weight there. I made a subchassis out of 1/2” square steel tube. The front service and underside of low chassis points have lead wheel (full sized) weights to counter acts the high CG. The body is heavy as well as the bumper. I have SAMIX portal covers on the front and believe it or not, that body is very heavy. The plate on the rear is also a steel plate with real rust. The interior will be heav as well as I am mounting it with L brackets and rare earth magnets. I’ve got a terminator figure as the driver too when I make the side windows and put it in.

I will see how a replacement set of gears does but it will take a month for them to even show up. I honestly don’t know that anyone couldn’t have a problem if they had a similar set of gears. I’m very disappointed.

[travis c.]

My rig weighed in at 5.1#s, gears never lasted more than 15 minutes.

FAWK MST AND ASIATEES:flipo ff:

[JatoTheRipper]

You added a lot of weight over stock. It would be interesting to see what your truck weighs, but 1/2" square tubing and steel rod isn't light. The gears simply aren't meant to handle that. The didn't hold up as well as I would have liked, but maybe you got a bad batch.

I would honestly contact MST. Send them your photos and let them know the gears are weak. Hopefully they replace them and hopefully things like this can convince them to give us hardened gears as an upgrade. MST usually makes high quality stuff.

[Teng]

It is exactly what I wanna to say. I found a lot of stock RC crawler favour in 2s Lipo pack. Any stock crawler on 3s Lipo will be shorten their life in gears, CVD, driveShaft etc... just as Jato mentioned as above. I hope you find out the solution soon. Thank you



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