Ball specs for wheel bearings

[roscoe]

I want to buy some ball bearings in bulk as they are much cheaper than from a bike shop. I know I need 1/4in for rear and 3/16in for front wheel but I need to know what type of material. Apparently I can get 316 stainless steel or 440c.

[DaveM]

I don't know too much about the difference in materials (is 440 heat treated?). But unless there is a huge cost difference, go with the better ones. Seems silly to scrimp on bearings when they are such a critical parts of the bike.

The only argument I've ever heard for cheap bearings is that you would rather have the bearing itself wear out before the cones on the axle or cups in the hub. The idea being that you purposely use weaker material on the part that is easiest and cheapest to replace. I guess it might have merit if you don't plan to maintain your bike and only inspect things once they completely break. But many people do ride that way. Anyone have any thoughts?

[buzz]

Depending on how many bearings you need, it may be cheaper just to buy them as needed. If you are running a shop or have several bikes you are fixing, it may make sense to buy bulk. But, I was only charged a buck for both sides when I overhauled the front axle this week. I have no idea about what ones are better.

[ozzzyrick]

316 stainless is a harder grade of metal than most stainless steels.

440 is a heat treatable carbon steel and the "C" designation is to say it is. If its done properly. The source of supply would help but some nations have differing standards.

If you frequent wet conditions then the 316 bearings lubed with waterproof grease would be best.

As for where you get them I would favour a bike shop that is either involved in racing or deals in servicing bikes only.

In reflection to Buzz's remark I wouldn't buy bulk unless it is practical. Feretic stainless will still rust in the right environment.

Rick.

[chris608zz]

440 grade balls will last longer as they are much harder. 316 is a more corrosion resistant but also non-hardenable steel. Marine bearings can be made from this grade but they are only for low load and speed. 440 is the standard grade for stainless steel bearings as it is hardenable and will cope with high load and speed. 440 will corrode with extended exposure to salt spray or salt water (unlike 316 grade) but yours will be protected by grease which I guess will have a anti-corrosion additive. See http://www.smbbearings.com/SMBtechdata.htm#bearingmaterial for more info on chrome and stainless steels.