Just bought.a Schwinn road bike and found d that when I shift into 12th.gear my chain wants to jump off. Looks like my cassette is very worn as no amount.of adjustments can get chain to stop jumping. The guy who sold it to me says I have impossible to find sun tour cassette. I do not know what to even look for as far as replacing these gears. Can anyone help this new ?? Pics Included
This should help. I see Shimano via II on.the rear hub..I think it safe to disregard what the seller told me as everything seems to be.shimano. I think he made up a lie about the parts being impossible to find to cover the fact that he should have fixed this issue or at least informed me about it.
Yup, freewheel. If it is skipping under load, you should just need a new freewheel (and should probably replace the chain at the same time though it looks fairly new.) It looks like you have friction shifting so you can use any brand freewheel. You can probably go up to 7 speed if you want (there should be enough room to fit a 7, though can't guarantee) or stick with a 6.
You can buy the tool to remove the old freewheel, or just stop in to a shop to have them pop it off for you (5 minute job). You don't need any tools to install new freewheel.
Thanks for the help !! Yes the chain skips under load. It is fine until load is put on it. So basically the seller was lying when he told me I have a sun tour setup which is impossible to find and that he would have had to replace the entire wheel to fix ??
I am going to remove the back wheel when I get home and take some more pics , because I could swear I saw the splines vs having the two indents on the inside of the cog.. if this was the case then I would have a frrehub cassette , right.???
Totally new to this , bear with me on the dumb questions
Here is a better pic. I do not.see the two notches. Are we certain.this is a freewheel ??
Looks like a shimano uniglide cassette to me. They are available on ebay, though not cheap.
Note that the slipping could be due either to worn cogs or to a worn interior ratchet in the freehub. In which case, new cogs won't help at all. Just warning you...
Seller was right, just had the wrong brand.
Teeth count is 13-29 if that helps. Also I can clearly see "Shimano products " stamped on the freewheel or cassette in question
Looking at the cassette teeth, they look ok not too worn out. So I do not think your problem is in the cassette. (BTW Freewheel usually has a wider hub at the gear end). I see lots of grease so looks like there was some service there. If the chain is jumping and not staying on the largest inner gear I'd suspect misalignment in chain line and the derailer. If you are trying to shift from the large front chain ring to the large rear gear that's too much cross over, you should not shift much more than half gears and than go to the inner front gear and continue shifting. Does the chain jump when you use the smaller front chainring with the large rear gear?
AS per PO do not be so ready to jump on him, the bike looks ok, perhaps he just did not know what he had, that's not unusual with most owners.
Never Give Up!!!