Guys, this was a new one to me. We were riding back from a meal out last evening, and I noticed the riding effort going way up over a short period of time. This is on my fairly new-to-me 2004 Giant Iguana mountain bike. I figured the rear brakes (discs) had somehow gotten partly applied, but it was dark and we were only about 2 km from home, so I rode home without trying a field repair. I could barely spin the rear wheel by hand. I took it off the bike and found the rear hub very hard to turn. The nice new grease I'd repacked the bearings with in July was leaking out, likely due to the heat generated. I figured there was more to it than just loosening up the cones, and tore it all down earlier today. The first thing I noticed was that the rear cassette was quite floppy. I removed it, but found that the black splined freehub shell was still floppy. (Please refer to the diagram in the linked site; I had no idea what to call these parts.) https:/
I'd never had one of these off before, but by trial and error learned that it's easy to remove with a 9 mm Allen key. Per the diagram, that's the freehub lockscrew. When I removed it, I could see that it was very worn - the end was almost worn away. Fortunately I had an old wheel and was able to transplant in the new part.
My working theory is that due to the wear in the lockscrew it wasn't holding the freehub body in place, and the bearings started to bind when the body shifted.
Anyway, it's all back together now, and I look forward to a test drive tomorrow. I put the bike on the road in July and have ridden about 400 km. It always seemed to have slightly more rolling resistance than I wanted. I hope that's cured now.
I should have taken photos during the work, and it got a bit crazy when I had both hubs apart and started mixing and matching pieces. Thus, when I first put things back, there was a clicking sound and high rolling resistance. This stumped me for too long, but I finally swapped a washer from one side to the other, which centered the disc properly in the caliper. Problem solved - I guess the disc is out-of-round, and a high spot was catching the brakes or the edge of the caliper. Anyway, all's well that ends well (I hope). www.instructables.com/ id/ Rebuild-a-bicycle-rear-hub/