maddog34

every pedal stroke causes lateral loading...

as to wet test... i'd rig a drip line to drip onto the bearing seal at about 2 drips per second... run that drip line about 1/3 of the time of the entire test... this will more correctly simulate an"all season commuter" use.... at least around my area! Road dirt is more complex than your proposed mix, too... car drippings, and various other acidic compounds will be found in the gutters and puddles... and then, there are the more organic debris mixes found along forest pathways. and on tree lined streets... MTB's see lots of CLAY around here, too... near a beach? the SALT is NASTY on steel...

i'd choose "metal dust cover" bearings to test, since MOST of the bikes only have those plain metal dust covers(think Walmart bikes)...

does the spindle, or some outside drive create the rotation on the test device? IF it's a spindle drive, then applying lateral loading could be achieved with a weight on an angled pendulum... then swapping the weight to the other side of the outer race occasionally...

and using an infrared temp. sensor "camera" would provide additional data, eh?

things i consider with various greases... temp. of operation... FLOWBACK of the chosen grease onto contact surfaces after use ceases, and weather proofing characteristics... Thick, high temp. greases DO NOT flow back when used on lower speed, lower pressure, bearings! this is why i constantly use lighter, "thinner" greases on bikes. I took apart a hub with marine grease in it just a few nights ago.. there was plenty of grease in the hub, but NONE on the actual contact surfaces!... no water or rust in the hub, but the cones were galled up from excessive heat!... the balls were shot, too.

try to find some of the OLD style amber grease, too... that stuff works ok, but breaks down over long time periods... the oilier part separates and runs out, leaving behind parafin wax that is NOT going to move until it gets thinned out with some lighter oil or penetrant solvent... think "really old schwinn hubs".. scrape some of that hard wax compound out, and force it into a cleaned bearing... see what the test results are... should be good for some laughs!

"carbon"... ALL greases contain long chain carbon molecules.... petroleum oil comes from deposits of trapped ALGAE BLOOMS that turned the oceans into pea soup, btw.... very few dinosaurs were involved.... and in fact, most oil deposits pre-date the dinosaurs by quite a long time... and the crude thins out, the longer it's been buried... The Labrea TAR pits are fairly recent deposits... the gasoline rich Lakota deposits are much older and deeper... they contain over 70% gasoline... no WONDER the oil companies want to get at it so quickly, eh? the crude looks like honey when it comes up the pipes... TAR SANDS are very young, relatively... and they have minimal overburden, allowing open pit mining.

geology relates to bikes... who'da thunk it!?!

another thought... include heat cycling into your tests... ride, park, ride... and keep the drip line running during the heat cycling cool down periods... not everyone parks their bikes inside... as the bearings cool, they WILL draw in water/grunge.... a well known factor.

so... you have long term access to the test machine, right? like... a couple years?

now... excuse me while i slice several wraps of rubbery tape from a seat post some logger shimmed up to fit the wrong bike.... i'd post a pic for laughs, but it looks too obscene! there was no seat on the post, either.................

UPDATE: it WAS a springy post, with the top slider gone, collar still in place....... imagine the shape after being wrapped..... yes, i wore gloves.....