Mojave Arrma please stop using the 15x21x4 inner wheel bearings👎

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Twins?
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Ngl, I had a bad landing on 1 tire from the ramp which led to that bearing going pop. Happened to my fireteam too and I was landing that really well.
 
I will say, that is one thing I think redcat did right with the kaiju. 8x16x5 bearings on both sides of the hub. Maybe it causes other issues (have heard of any) or are too small, but if anything it's easier to keep bearings in stock, they should last the same, and just overall easier to manage imo.
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Vitavon. All the way. I often don’t recommend aluminum replacements for bashers, but the hubs often break while bashing and, as mentioned, the inner bearings suck. I’ve spun races in RPM hubs, which I would have never expected. (Even though I’ve historically gone on record to voice my disdain for their a-arms.) I think the Vitavon “redesigned“ 6s hubs with larger bearings are just the best mousetrap. As the hubs in my Arrma rigs eventually fail, they’re replaced with them.
Yes, I saw that Hot Racing also makes aluminium hubs with a larger inner bearing.
I‘m hoping Arrma will (or hopefully already has) put it pretty high on their TO DO list, since they use their current design on 14 of their cars, according to their website.🤞
 
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While I'm not arguing about the size of the inner bearing being wrong whatsoever, I would like to offer what I have learned in many years of bearing's failures...

Sand should not be a problem per se, but it does produce friction and therefore heat. Water and mud are much worse, as it is a high jump where there is no enough play for the dog bone/CV to move freely.

As the bearing gets hot, even if they are sealed, they will take water and moisture in and will inevitably seize as the outer ring will contract quicker than the internal balls and the inner ring.. If the CV/bone doesn't have enough play it will hit the bearing on the sidewall of both rings where it has no real strength. Once the balls are pitted, the heat will go up even quicker and the failure is guaranteed..

That's why in the automotive industry we use Conic roller bearing instead of straight ball bearings... Same reason why you should never wash your RC car just after a run as most of those metal part will be hot and cold water would definitely do some damage... It would make no difference if using brass bushes as they shrink even quicker when in contact with cold water or mud.

Unfortunately nearly 100% of these bearings we are using, (no matter what brand) are from China and there is simply no quality at those prices and the size of the balls and the size of the cars, definitely doesn't help...

We definitely need bigger bearing for the 1/7 and 1/6 scale. Those bearing are barely coping in the 1/8 and 1/10 scale. I change them on a monthly basis (two races per month) on my RC8B3... It helps to buy them in box of 50 from a bearing supplier, as the prices really does come down a lot...
It also helps to spend some time in reading about all the different ABEC rating for bearings..
 
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