Cheap Bearings or Bushings?

[frameskip]

Inspired by some of the really nice TA02SW Porsches I have seen on the site, (Truck Norris, rr92zer), I have picked up kit #47321. I also grabbed a sealed bearing kit, but thought I might use metal shields for the gearbox internals. Given the good experiences of others, I took a punt on some really cheap 1150s from China. When they arrived, they were quite rough, so following @Juggular's recent bearing mania from the "So, What Have You Done Today?" thread, I decided to open them up to see if I could get them to spin more smoothly.

The short answer is "no".

Part of the problem may be that there are only 7 balls in these 1150 bearings (rather than the 9 I see in Juggular's), which got me to thinking: which is worse? A plastic bushing, or a cheap/rough ball bearing? What are the effects of a crunchy bearing over time?

[max69vk]

As poor or rough as a bearing may be, provided they don't have a a ridiculous amount of slop or play in them, they will always be better than bushes. Bushes are literally friction generators as 2 surfaces wear against each other, lubricating them doesn't work either as if you get any dirt in there it just makes things worse.

[Losi XXT-CR]

The only way to know for sure would be to measure the resistance. Probably not easy to do accurately. But could be done as a guess. Set the bearing up and rotate it and count in time how long it takes to stop or how many revolutions. 

Repeat with the bush. Ideally with the same initial force and same weight components. I’d expect more heat with a bush. So you may need to factor in what happens after extended use. 

[TurnipJF]

You have spent a good bit on a really nice kit - why cheap out with the bearings/bushes? A decent car deserves decent bearings.

 

I'd discard the dodgy Chinese offerings and get some quality ones from RCBearings.co.uk.

[lentner3]

7 balls in the bearing doesn’t always mean less efficient than 9. The casings are more a factor. I have used rc bearings for many sets probably 15 plus sets. I’ve also used the cheaper sets from China and they have been equally good. I personally would avoid the rubber shielded bearings unless getting the more expensive ones. Yes they keep water out slightly better but the increase in friction negates any improvement. My vote is bearings from China and keep them clean. Give them a wipe down after getting them wet. I have a lot of experience with skateboard bearings and won’t use rubber seals again. Unless you want to pay through the nose for ceramic bearings anything will do. However all being said RC bearings are not a lot more than getting them in from China and worth the extra couple of quid just for speed of delivery and great service. The only reason I sometimes get them from China is I have been restoring a lot of TL01’s and they take 24 1150 bearings so purchased 6 or so sets at £6 a pop so not to deplete my spares. 

[frameskip]

All good points, and bushings have definitely been ruled out from the start!

The sad part is that the rubber sealed bearing kit is from a reputable seller and I only decided to add the metal shielded to the internals after the fact... hence cheaping out with the China bearings. I already have some decent 850 metal shields from a previous purchase, so it's just the 1150s I need. Time to go consult the manual and then off to RCbearings.

[lentner3]

Rc bearings will put together any combination you need send him a message first he is very helpful. In my experience it’s always handy to have a handful of 1150s in your spares. The most common and important size. 

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8 minutes ago, lentner3 said:

Rc bearings will put together any combination you need send him a message first he is very helpful.

That is very good knowledge for future reference -- thank you!

[Kingfisher]

3 hours ago, frameskip said:

All good points, and bushings have definitely been ruled out from the start!

I know you've said you have ruled out bushings. Just to put a visual on what's been said. I recently got a used WT01, which had bushings in the gearbox. Here's how the shafts looked when I took the bushings out.

 

 

[nowinaminute]

Geez I've never seen one that bad INSIDE a gearbox before! Was there grease in there? How about dirt? Plastic or brass bushings?

I only ask because I'm normally surprised by how decent old gearboxes have looked inside despite having plastic bearings in there, the last one was an old Lunchbox, the outside bearings had oval shaped holes and the metal worn down but everything inside the gearbox looked great considering! Also seen the same kind of thing with a Boomerang and a Falcon awful outside but quite good inside.

[Juggular]

I've occasionally seen wears like that.  I've got a feeling that it only takes a few hours to rub like that.   

For cheap bearings of decent quality...

@nowinaminute wrote on "Postman brought me" thread on 1/17/2018:

 

Just some 1150 bearings, nothing exciting. 

These are the cheapest I have found that are still reasonable quality. There are several listings for them on ebay, they work out about £1.50-1.70 for 10.

They are "NMD" branded which is a reasonably well regarded brand. I have no idea if they are factory direct or pulled out of surplus equipment but the fact that every bag of ten always has 2 that are black on one side instead of green makes me think it might somehow be the latter.

Regardless, they seem decent quality and smooth enough for general purpose use. I once tried some even cheaper metal shielded ones but the "grease" in them was literally like glue and once I cleaned and relubed them they had terrible play. These are by far the best combination of cheapness and quality I have found.

[Kingfisher]

2 hours ago, nowinaminute said:

Geez I've never seen one that bad INSIDE a gearbox before! Was there grease in there? How about dirt? Plastic or brass bushings?

I only ask because I'm normally surprised by how decent old gearboxes have looked inside despite having plastic bearings in there, the last one was an old Lunchbox, the outside bearings had oval shaped holes and the metal worn down but everything inside the gearbox looked great considering! Also seen the same kind of thing with a Boomerang and a Falcon awful outside but quite good inside.

I think it was lubricated with bubble gum. 

More pics and info here:

https://www.tamiyaclub.com/forum/index.php?/topic/85220-i-bought-my-first-roller-4x4x4-build-thread/&tab=comments#comment-700100

 

[Grave Digger1]

I always use Duratrax bearings and I've never had issues with them.

Lynn

[WillyChang]

These days even the cheapest available China BBs are serviceable & work fine for our RCs.

In that industry "hobby grade" is pretty low on their grading scale... at least until "fidget spinner grade" came along... now I know what they do to get rid of all the junk rollerblade 608s that are rejects even from the travel luggage wheel factory  they ain't much better than steel discs as ballast.

[Carts]

My £6 rubber metal bearings from Hong Kong turned up this morning, fitted them to tt01 and are fine. Runs smooth as