OP: Prowheel; That's the exact bearings that are on my 2X upgrade crank that was a super deal. Mine are still going strong, 4 years and a lot of miles later.
Originally Posted by
Ron Damon
Forget replacing the bearings. Replace the entire unit instead.
You'll need a Hollowtech 2 (HT2) BB wrench to unscrew the current BB and screw on the new part. When installing the new unit, the axial compression is key so as to not damage the bearings from too much or too little pressure. It's not rocket science or brain surgery either so I'll spare you the service manual dissertation.
Pro tip from the work-bench: the size of the threading on the two suggested BB is different. Make sure the wrench fits the one you choose. Better yet, buy a wrench with both sizes.
"Replace the entire unit": Do you mean crank and all, or by unit you mean the entire bearing cups? Yeah, I wouldn't try to press out the bearings from the aluminum cups, I'd buy whole new external bearings, they were engineered to be low cost.
Axial compression (preload): The torque value will be printed on the end cap for the spindle. It's really low, and if you don't have a torque wrench that goes that low, convert the number to inch-pounds (your search engine will do that or take you to a website that does), and exert pressure on the end of your allen wrench accordingly. Mine says metric and english which is 6-13 inch-pounds, so if I aim for 9 inch-pounds and my allen wrench is 3" long, I'll push or pull with 3 pounds of force to multiply out to 9 total.
Remember: This will need retorquing after the bearings burnish-in, typically a few months of daily riding. Some premium bearings, like DuraAce, at least at one time, came factory-burnished.
"Buy a wrench with both sizes": When I bought mine, it was nominally more to get one with 4 sizes, however this is a dogbone wrench; If you buy a cup style to fit a square-drive torque wrench, you can only have two sizes, I think. With my dogbone-style wrench, I calculated what my hand force should be, just like with the end cap, and torqued into place accordingly, not that difficult.
After in place, I put a small dot of red nail polish on both cups at the 12 O'clock position when the bike is standing up. That gives a clue if a cup is coming loose. I also did that on my rack bolts, after one came loose and sheared off.
EDIT: Man that weld is close. When you have the old bearings out, make sure that none of that weld is over the edge onto the flat face of the bottom bracket shell, that would goof things up.
EDIT: Those bearings look a little weird to me. IIRC, on mine, you could see the separate inner race rotating with respect to the fixed outer race, with a seal between them. On yours, there appears to be a big rubber seal over everything, which sounds good, except the inner crank surface is moving and rubbing there, and is held tight against the bearing by the end torque cap. That might be a different setup. Maybe that whole rubber seal rotates.