Bushings/Bearings : How significant are they?

[Rabbit]

Bushings/Bearings are something i've never really done much reading into - only in the case of replacing plastic ones with metal for durability.

What really is the difference between 6mm, 7mm and 8mm? Even 9mm.

I've read that 6mm are ok for 350fps and lower set ups and any higher FPS should be done with 7mm or 8mm.

Solid bushings are more reliable than ball bearing ones, but for an increase in ROF you can keep a ball bearing set on the bevel gear.

Thoughts? Facts?

[ThunderCactus]

A bushing is a "bearing surface", but what you refer to as "solid bearings" are bushings

bearings aren't required in airsoft. The bushings and gear shafts are hardened so wear is very minimal.

The only time you need bearings is to increase ROF to ridiculous, or otherwise reduce friction to increase battery life. And then, you should only ever use kanzen bearings. A shitty G&P bearing, after wearing a bit, can be just as bad for your high fps gun as a plastic bushing.

The bigger the better. Smaller bearings yield higher max rpm, but you don't come anywhere near even being close to the max rpm of a bearing in the mechbox.
Larger bearings can easily handle greater angular stress, which is what you need.

[Rabbit]

So how practical is it to run say just under 400fps on 6mm bushings?

What kind of shit could I run into?

[Stealth]

It's practical. 6mm bushings can handle just about anything you throw at it. In fact, that's what everybody was running back in the 90s. They could handle limit-less FPS.

Bushing size only increased because of the "need" to run bearings for increased efficiency and speed. Realizing that 6mm bearings could not handle the loads exerted, 7,8 and 9mm bearings were introduced into the market. And let's face it, it was just an excuse for airsoft manufacturers to sell you more bearings and gearbox shells.

[lurkingknight]

in terms of a bushing, any size performs the same, where the sizing on this issue matters is a bearing.

The larger, the stronger it will be due to the ball bearing size, but the larger the bearing assembly gets, the wider it will sit, and some gearboxes and receivers have issues fitting larger bearings.

People round here will argue against this, but I am an advocate of epoxying bushings into the gearbox shell. This takes up the slop the bearing might have side to side that might throw off shimming and it will also prevent the bushing from spinning in place which can lead to the holes being enlarged and bushing to fit looser or heaven forbid so much slop is introduced that your gear meshing becomes affected.


Bearings can slightly increase your rounds per second (I measured 2 or 4 rps in 7mm CA bearings to bushings in my g36), but at the cost of reliability. Also if you're not used to the free spinning nature of bearings, they can mislead you to thinking you have a good shim job when in fact it might be too tight. I've had 7mm bearings fly apart.. the races just self destructed and the spur plowed into the side of the gearbox shell gouging it and grinding some teeth on the sector and spur. You'll never see that with a bushing.

[Azathoth]

Originally Posted by ThunderCactus

The only time you need bearings is to increase ROF to ridiculous, or otherwise reduce friction to increase battery life. And then, you should only ever use kanzen bearings. A shitty G&P bearing, after wearing a bit, can be just as bad for your high fps gun as a plastic bushing.

Any quality bearings will do the job. Look at RC shops and in some cases fishing suppliers and you can find high end bearings that will do the job. depending on your price range 5.00 ea to $130ea

[Ron-E]

What about Modify 8mm Ceramic Bearing Bushings??