Originally Posted by
GreatWhiteShark
So, far, spent more than an hour and a little over $60, and a lot better (new back gears, new brakes lines and gears lines and gear shifting works again), but it still attaches and releases when I stand on the petals to start going again. I already too it back, less than block and then they replaced the back gears. I do not have that sort of money, and I am now, thinking I might need a better mechanic (I recommended to them my former Independent Bicycle Mechanic who lost his home/work location), $60 (like 6-times what I paid before) and all they could think of, at that time, and still the catching and releasing exists. The shop's mechanic only adjusted Rear Derailleur settings, I am thinking maybe, need to replace parts to it or it all together. Plus, I know from past when all the catching and pulling and releasing going on erodes the gears clusters; so maybe the front gears need replacing to. Last thing is they have back gears for 18-speeds, while my bicycle is originally for 21-speeds, original shifting, just not original gears. You guys think, switching like that, without replacing the shifting handle bar's mechanism can contribute? Thinking of maybe, trying to find a CoOp Bicycle Shop, again.
Shift the bike down the smallest rear gear, and then try to take an in-focus picture of the rear gear set (cassette) AFTER you've brushed most of the gunk off. I'm guessing a few people can probably tell you if you need a new cassette or not.
Unfortunately, operating a bike with a worn chain can lead to extensive cassette wear and needing a replacement. One way to tell if the cassette is worn or if a 6 vs 7 speed issue is if it skips in the largest back gear. The derailleur position will be determined by the limit stop not by any indexing. If it still skips the cassette is likely too worn.