Well I'm happy to say the project replacing the crank spindle and bearing assembly the vendor I bought my spin bike from sent me was completed today. I'd had the parts for some time but was waiting on some drifts of the appropriate size I ordered and some high grade grease from another place to press the new bearings in and put decent marine grease on the assembly.
I ordered an expanding blind side punch out bearing remover too, but didn't use it. Reason being I had a bad idea of trying to rejuvenate the original bearings. I ended up damaging a seal on one of them stupidly assuming a large flat blade screwdriver would distribute the load better on the outer race when taping out the first one, but the screwdriver slipped onto the seal.
I had a small punch that worked much better. However I could not get the rust stains off the outer side of the inner races, so I chucked them thinking it's not worth risking that rust spreading to the new spindle. I DID however pop the seals off the new bearings, flushed the grease out with degreaser, and filled them with the high quality marine grease I bought (Jet-Lube Marine MP).
My bearing press worked well to press in the bearings, but I made the mistake of starting a bit too quick, which left the non drive side one going in straight, and the drive side one starting a hair crooked. So I gently hammer tapped the outer race a few times on the side protruding more, then finished with the press. By then the new spindle was Icy cold from my freezer and shrunk down just enough to slip easily into the bearings, but of course it got a light coat of the grease on it first.
The hardest part of this job is definitely getting the belt off and back on. Using the tip of my belt helped coax it off, tricky, but not as difficult as I thought it would be. The belt had sat without tension for weeks though while waiting for the stuff I ordered, so it was a real bear to put back on. It doesn't help that this manufacturer doesn't give you long enough tensioning bolts or axle dropout slots to get enough slack to easily take it off and put it back on like some manufacturers do.
I tried leaving the non drive side of the flywheel axle in the dropout in as slack a position as possible, and taking the drive side of it's axle completely out of the dropout. It was too hard to try and pull the drive side axle of the flywheel into it's dropout with the belt in place though. I also tried putting the drive side secured in as slack a position as possible in the dropout, then using the tip of my belt again to try to roll the bike belt onto the crank pulley, but no go, kept slipping off.
I finally got it on just pressing the belt hard toward the plastic pulley. This started working better as the rubber belt was gripping the edge of the pulley. This momentarily deformed one edge of the belt, but I finally got it on. I decided to tighten the tensioners less than they were from the factory, as the belt had hardly any deflection pressing hard on it with my hand. I figure this way my drive side crank bearing might last longer. I can generally tell when a belt slips, and in testing it after at a full resistance standing sprint, there wasn't a hint of slippage. There's also zero noise now when I pedal with hard resistance. The reality is this bike has just enough resistance for me, but not enough to really make the belt slip.
Next project is fixing the slow leak in the front wheel of my new mt bike. I'll be putting new rim tape on it, and likely ordering some TPU (Thermoplastic Poly Urethane) tubes with threaded valves this time (the non threaded plastic ones suck). Haven't decided whether I want to go with the glued seam Guee brand from Taiwan, or Silca's German made ones with RF welded seam. I'm thinking a good compromise might be ordering just 2 of the Silcas, and using one of the Taiwan ones for a spare. They both have decent stems, but I'm skeptical about the very thin TPU the Silca's have. They're about 2/3 the weight of the Guee, not much more than what skinny TPU road tubes weigh.
I keep thinking the Silcas might be an expensive mistake. The ONLY reason Silca went with such thin TPU is they wanted to get within like .2 percent of the rolling resistance of latex tubes. This is because Silca designs a lot of their stuff to work well even for pro racing. I don't think the latex tube market is relative enough to compare to these days though, most riders don't use them anymore. It's also kind of a telling sign when part of Silca's justification of the relatively high $39 asking price for these tubes is that they come with an alcohol swab and one patch. I'm pretty sure most racers don't want to be patching a flat mid race. The Guees are $25 a tube. I know TPU sounds expensive, but they're becoming a favorable alternative to tubeless due to being very close in rolling resistance without the maintenance hassle, and the cost is pretty much a wash too, even with the higher quality TPU tubes.
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