Chain question

[swk3000]

I don't know where to put this, so I'm putting it here. If it's in the wrong place, I apologize.

My sister has a single-speed bike that she uses to get to and from work. The pedals no longer work. The pedals turn, and the chain turns, but the chain no longer turns the back wheel. Is there any way to fix this?

[FredS]

Can you post a photo of the chain and gears, if it is an older bike the chain may need replacing and the gears may be worn.

[swk3000]

Gotta love SnapBucket.

Here is the rear gear.



Here is the front gear.



And here's a (blurry) picture of the chain.



Also worth noting: before the bike quit working, it was working badly. If you coasted the bike at all, when you started pedaling again, you'd have several rotations where the chain and pedals wouldn't catch the rear wheel. You had to keep pedaling constantly to keep up speed.

[nfmisso]

Most likely you need a new rear wheel. Inside the hub there are pawls that engage the wheel when the pedals turn, they have probably become very gunked up.

It appears to be a 20" wheel - read all the information on the tire, and post it, and we'll be able to tell you for sure.

If it is a 20" wheel; then this would most likely work as a replacement:
http://www.amazon.com/Avenir-Alloy-Coaster-20-Inch-1-5-Inch/dp/B0048MD90E/

To extend the life of the bike, it needs to be cleaned and lubricated.

[swk3000]

It's a 20", alright. 20 x 1.95, specifically. I'll have to see what I can find at stores in my area; my sister needs it as soon as possible. Still, replacing the wheel shouldn't be difficult; should just be able to by a new one and swap it out.

[Joe_W]

If it is a normal single speed then the ratcheting mechanism is inside the freewheel and not inside the hub. Check that first (search for hub type online, there should be some markings on it) and check what it is...

[swk3000]

How do I check Hub type? And is the Hub the front gear (where the pedals connect)?

[nfmisso]

Here is a hub:
http://www.amazon.com/KT-Coaster-Brake-105G-Type/dp/B000BMRQPE/

This is what Joe is referring to replacing - to do this you need to know EXACTLY what you have, and the tools to remove the free wheel from the hub.
http://www.amazon.com/Hub-Coaster-Brake-Shimano-Trim/dp/B004E3R0VQ/

To me, it sounded like you wanted a quick solution with no special tools or skills, which is why I suggested a new wheel.

[swk3000]

Ah. I don't have the correct tools to swap out a hub, so a new wheel will be the easiest way to do it. Thank you. I appreciate the help.

[nfmisso]

(07-07-2012, 12:43 PM)swk3000 Wrote:  Ah. I don't have the correct tools to swap out a hub, so a new wheel will be the easiest way to do it. Thank you. I appreciate the help.

If you tell us where you are located, maybe someone on this board can assist you.

[swk3000]

Bit of a snafu. I went out and bought a new wheel, but it's a 16-tooth freewheel. The one originally on the bike was a 10-tooth cassette something-or-other. So I have a $50 wheel that doesn't work. I can't get back to the shop to swap it out before my sister needs it, so come Monday, I'll be going down to see what I can do.

I'm in Phoenix, AZ.

[Joe_W]

(07-07-2012, 12:36 PM)nfmisso Wrote:  This is what Joe is referring to replacing - to do this you need to know EXACTLY what you have, and the tools to remove the free wheel from the hub.
http://www.amazon.com/Hub-Coaster-Brake-Shimano-Trim/dp/B004E3R0VQ/

To me, it sounded like you wanted a quick solution with no special tools or skills, which is why I suggested a new wheel.

Actually: no. Since it was a single speed bike I assumed it could have a track hub with a single speed freewheel such as
http://www.cnc-bike.de/product_info.php?cPath=165_548&products_id=11237

However: looking at the picture again, the hub body really is quite thick (much thicker than a typical single speed hub), so it could house a lot of mechanical stuff. Then, the ratcheting mechanism would (of course) be a part of the hub and (maybe) difficult to service. For some hubs (eg. Mavic) this is serviceable and easily accessible. This is why you should to find out more about the hub (manufacturer, type, ...) sometimes stuff can be serviced, sometimes not. I' get a new rear wheel (and try to fix the old one, if possible, as a backup).

Edit:
Oh, and the sprocket might just be screwed on then... you can take off the old one and put it on the new rear wheel.