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Taught/loose chain issue:'63 Raleigh Sports

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Love that red! So, have you had this on the road before all this? Is it possible that the bottom bracket housing (not sure what to call it) was welded on slightly off? Just throwing it out there.....
 
Hello everyone,

Again , thanks everyone for your time and expertise. Yes I moved all the drive components from one bike to the other and only have this situation on the red bike. Drive components I moved from one bike to the other include entire rear wheel, bb axle/spindle, chain ring, bb adjustable cup (non drive side), chain (red bike has original chain but to eliminate potential root cause I also put a new one on). the red bike functions just fine when I adjust the tight spot to 1/2" (loose spot to 1") so I guess that's what I will do. The only part I did not move from one bike to the other is the bb drive side cup. Was just trying to get it "perfect" but I guess things really never are. Btw regarding the hub I totally disassembled and cleaned and added 5cc of 20w non detergent oil and it shifts and runs like a dream . red bike is AW hub and black tcwIII (coaster brake). Interesting fact Is both bikes have rear hubs from may, 1963.
 
Hello everyone,

Again , thanks everyone for your time and expertise. Yes I moved all the drive components from one bike to the other and only have this situation on the red bike. Drive components I moved from one bike to the other include entire rear wheel, bb axle/spindle, chain ring, bb adjustable cup (non drive side), chain (red bike has original chain but to eliminate potential root cause I also put a new one on). the red bike functions just fine when I adjust the tight spot to 1/2" (loose spot to 1") so I guess that's what I will do. The only part I did not move from one bike to the other is the bb drive side cup. Was just trying to get it "perfect" but I guess things really never are. Btw regarding the hub I totally disassembled and cleaned and added 5cc of 20w non detergent oil and it shifts and runs like a dream . red bike is AW hub and black tcwIII (coaster brake). Interesting fact Is both bikes have rear hubs from may, 1963.
You're giving up!? There has to be a relatively simple explanation for this issue. Clearly something is out of round.
 
next thing I am going to try is replace the bb drive side bearing cup; it's the only thing I haven't tried yet. Once I locate ,purchase, and install , I will post an update. Thanks again to all.
 
Being a single speed rider I have almost never seen a chain that doesn't tighten and loosen as it goes around. The standard for looseness is 1/4 to 1/2 inch of up and down at its loosest. That is because of the factory tolorences. Roger
 
Hello Bulldog1935: yes I inspected the chain stay, bb, and rear drop outs for cracks and see none. Bike had a very sheltered life. I completely disassembled, inspected, and cleaned. I like your idea of setting up a run out indicator to measure eccentricity of chain wheel but for the moment I don't have the equipment. I will put on my wish list for these situations.

Does anyone have an opinion on my theory that the drive side bottom bracket bearing fixed cup could be unevenly worn causing a slight wobble of the chain wheel ? Remember that is the only part I have not removed and swapped out . Above I have pictures of the non-drive side bottom bracket adjustable bearing cup. Do the bearing race surfaces always wear evenly as you go around the race or do they wear unevenly since pedaling forces are only applied every half revolution?
 
...Do the bearing race surfaces always wear evenly as you go around the race or do they wear unevenly since pedaling forces are only applied every half revolution?
usually, the balls go flat, but if you haverace wear it will probably be in phase with mashing loads on the crank - that's where contact stress is highest - and yes, that could produce BB eccentricity. .
 
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