Bicycle Mechanics - Cannot pedal backwards or stop pedaling

I bought a bike a yard sale. And it has this problem. When I pedal backward while coasting or don't pedal at all the chain get more and more caught until the bike is unable to go any farther. I think it might be the bearings in the rear wheel but would like some opinions on it.

Sounds like a fixed gear.

What kind of bike is it? Does it have gears? If it has gears can you shift them? WHat happens if you just try and turn the crank backwards by hand?

If you walk the bike, do the cranks turn by themselves?

It is a Shimano NEXT 21 speed. Gears seem to shift ok - I think they need to be tuned up. If I flip the over and turn the crank backwards by hand it does the same. When I walk the bike the cranks turn by themselves.

Gummed up freewheel?

http://www.sheldonbrown.com/freewheels.html#lube

I agree with the freewheel lubing, but it could also be a rubbing spoke protector.

Check to see if it has broken loose and is causing friction on the back of the cogset.

It says "The sprocket will be stationary, since the wheel is coasting, but you'll see an inner part of the freewheel that is spinning with the wheel." on
http://www.sheldonbrown.com/freewheels.html#lube

The problem is the sprocket is not stationary it is moving.

Anyone have any ideas why when coasting the sprockets turn?

Anyone have any ideas why when coasting the sprockets turn?

It's because the mechanism is gummed up just like 04jtb said.

Spray some WD40 into the middle of that sprocked cluster. Give it some time to seep in and give the rear wheel a spin with the cranks. It may take two or three applications but my bet is that'll fix it.

Definately sounds like a gummed up freewheel. On older bikes the grease in there gets old, thick and doesn't let the freewheel move properly. I would recommend just replacing the freewheel. Take it to your local bike shop and have them look at it also to make sure. A new freewherel normally runs around 40$-50$ with maybe a five dollar install charge. This way you don't really need to worry about it crapping out on you anymore. You could us WD-40 but I'm pretty sure if you use WD-40 to loosen up the freewheel, you'll have a freewheel that spins but doesn't have any grease in it. The WD-40 is made to brake up grease and frozen parts but then evaporate so you have nothing left and your frewheel is gonna wear out very quickly.
Hope that helps!

Definately sounds like a gummed up freewheel. On older bikes the grease in there gets old, thick and doesn't let the freewheel move properly. I would recommend just replacing the freewheel. Take it to your local bike shop and have them look at it also to make sure. A new freewherel normally runs around 40$-50$ with maybe a five dollar install charge. This way you don't really need to worry about it crapping out on you anymore. You could us WD-40 but I'm pretty sure if you use WD-40 to loosen up the freewheel, you'll have a freewheel that spins but doesn't have any grease in it. The WD-40 is made to brake up grease and frozen parts but then evaporate so you have nothing left and your frewheel is gonna wear out very quickly.
Hope that helps!


$40-50 is way too much to spend getting a used department store bike working again.

ebay a freewheel, it'll probably run you less than 20 bucks shipped if you are a little patient.

I don't know where you guys are shopping, but you can get a new freewheel for around 10 bucks, and add another 10 for a new chain.

Try the WD-40 and then oil thing first though.

Have you tried a garbage compactor?

Have you tried a garbage compactor?

The NEXT might damage the compactor and it's worth more than the bike.

The NEXT might damage the compactor and it's worth more than the bike.

Wow.

Anyone have any ideas why when coasting the sprockets turn?

See the earlier posts that already laid it out for you. Either that, or junk the bike if you do not want to take the advice.

-Kurt

Wow.

Have you priced compactors (http://www.homedepot.com/webapp/wcs/stores/servlet/Navigation?N=10000003+90401+503391&langId=-1&storeId=10051&catalogId=10053&Ntk=AllProps)?

Excuse my cynicism, but after seeing many, many bikes of this type come into the shop, I understand why many other shops refuse to work on department store bikes.

Believe it or not, I'm not specifically bashing the quality, just addressing the economic factor that repairs on this type of bike often exceed the value of purchasing an entire new bike, especially when purchased secondhand from yard sales and such. If the OP can get a running bike with a minimum of cash outlay, such as oiling the freewheel or freehub...more power to him, but in my experience bikes that are neglected to the point that the freehub/freewheel stops working have many more issues to address. If it needs even as much as a freewheel or freehub replaced plus the labor charge or the purchase price of the specialty tools required for the job...then it's likely to exceed the price paid. A 21-speed Next (http://www.walmart.com/catalog/product.do?product_id=2513008) is about $80, used prices typically half that. It's simple math.

See the earlier posts that already laid it out for you. Either that, or junk the bike if you do not want to take the advice.

-Kurt

Well, I have tried the suggested several times with no luck. Perhaps though, it may take a few more times.
I have also thought about forgetting about this one and just get a new one. I was hoping that I could get it working without spending any money! But probably not!

Well, I have tried the suggested several times with no luck. Perhaps though, it may take a few more times.

Dribble the oil/WD through either side in copious amounts, angle the bike in such a way that gravity will help work the oil down into the mechanism, then spin the freewheel against the grit until it eases up. Keep it up vigorously - if not aggressively - until it begins to ease up. If you can work with someone else at the same time, have them spray/oil the inside of the freewheel at the same time you spin it. In other words - drench it.

Either that, or get a new freewheel from the LBS or complete rear wheel w/intact freewheel from a parts dealer.

-Kurt

get a gallon of mineral spirits and a roll of HEAVY DUTY aluminum foil.....remove the wheel...mold a "bowl" of aluminum foil around the freewheel and a few spokes for support(don't poke holes in the foil)........lay the wheel down so that the "bowl" will fill with mineral spirits......fill the bowl until the freewheel is submerged. Let it sit a day. Carefully undo everything (dispose of the chemical properly or re-use it) and the freewheel should be clean enough to resume working.

By the way, do all of this away from flames and vegetation..........mineral spirits kill vegetation..........

and flames kill the spirit.......:)...