[Whiskey]

Originally Posted by HKGhost

Why is it better to use bearings instead of solid bushing for 8mm? I've always believed that solid bushing was better because there is a less chance of failure. I was told that bearings are only good for high ROF and solid bushing are best for high FPS. I'm only sticking with my 8mm bearings because I'm not running a high ROF and I don't have any problems with them.

Bushings are crap (unless your mechbox is 6mm then you really have no choice). Simple fact bearings have less rotational resistance than bushings and givin you purchuse good quality bearings (kanzen comes to mind) you shouldnt have problems with them reguardless of the load or speed of your set up. Think about the solid steel axle on your gear set, now think about the solid steel bushing. Those two pieces are creating mass amounts of friction when your gear train is moving and both (givin the material density is the same or close) are wearing out causing more and more play between axle and bushing making your gear train less stable and more prone to failure. Yes one may argue that they grease these two parts but the loading from the gear train will eventualy squeeze this lubricant out of the bushing journal and cause metal to metal contact. I am aware that there are a number of brands that produce a bushing with "lubricant grooves'' in the bushing channel but this is not really helping the situation much as there will still be metal to metal contact were the grooves are not cut in the journal ( these groves dont dispurse lubricant they just kinda trap it in 1-2 areas in the bushing journal)
If you have the option for bearings 7mm minimum, I would recomend using them.