- Mar 18, 2017
Visual inspection definitely - for signs of wear and/or pitting, along with photos. Weighing on a precise scale will be an addition, to (double) check for wear. Since the bearings I plan on using are cartridge ones, not practical for disassembling, weighing will show any worn off material. Weighing before test (after degreasing and cleaning), then adding grease, testing and weighing afterwards. For fretting test - yes, my plan so far doesn't include the test - and yes, it's important for steerer bearings. Maybe on another occasion. I'll see how this goes. Next week I'm going to talk to the lab guys and see what exactly we can do, how much time will be available. As for bearing construction and wear - I've read quite a bit so far, but very little data on steel vs ceramics. In my experience - dirt intrusion and grease depletion is what kills most bike bearings. Ceramics are practically immune to grease depletion (no rusting, no welding, need very little lube to run smooth), but after a few rides and dirt intrusion - I doubt they differ much from steel ones. Using simple dust seals to prevent dirt intrusion does increase drag. On top of that, I'm still looking for a test of how faster a bike rolls with ceramic bearings, especially after a few rides in the rain.
Originally Posted By: Kestas
I think you should exclude the kerb crash test. This test is used to test the raceways for dent resistance. As I said, grease is not a variable in this test. You could run it without grease and have the same results. The tire is included because this is how the test was developed. The test has very specific parameters (i.e., drop height, load, angle) that I am mot intimately familiar with. There are books in the library of educational institutions that cover bearing design and theory. Common bearing failure modes can be found on the internet. Your water and dirt tests have merit. I wouldn't measure wear by weighing the bearings. It's not practical and it won't yield anything useful. Wear is typically assessed by examination of the raceways. It's not really quantified. Another test that may be useful is a raceway fretting test. This tests the effectiveness of grease during micromotion of raceways, such as the steer tube bearings. Different greases have markedly different results with this test. I believe there already is a standardized test for this in the industry.