Chain skipping or freewheeling?
 

I don't know which of these 2 things my chain does, but it's not good! If I apply much pressure at all to the pedals when riding, a "skip" occurs as if the chain is slipping off the gears briefly, or something else is happening. It's a sudden jerk that causes my feet to slip off the pedals. So when I ride this bike, I have to pedal very, very gently and build up speed very gradually.

I've tried to figure out what is happening by watching the gears while riding and applying more pressure when pedaling to make it skip. It doesn't [I]appear[I] that the chain jumps off the gears. Also, I've put hard pressure on a pedal while stationary while applying the brakes at the same time so I could watch everything up close. It "skipped" and my foot slipped off the pedal and I scraped my ankle on it.

I've sprayed lube on the chain and also into the hub. It didn't help. I also cleaned the chain, which didn't help either.

This is a bike I've ridden alot in the rain and Winter, which I understand can cause problems.

Does anyone know what might be causing this problem?

Does this happen in any particular gear? If so, it may be chain or sprocket wear. If it happens in all the gears, it may be the freewheel mechanism.

It's all gears. I meant to mention that before.
So what would it take to fix something like this? Would it cost much?

a bike store could tell in a second if your chain is bad.

if not, then its probably the freewheel or freehub depending on the bike.

a freewheel (mostly on older bikes, and some new low end stuff) are $30 or something plus maybe $10 or something to put it on the wheel.

not sure what a replacement freehub costs, if your rear hub even has a replaceable one. shimano hubs probably do, others, maybe.

You can try spraying the freewheel with something like WD-40 to flush out whatever might be in there and spin the freewheel as you do ,and relube with a light oil . If that doesn't work then you'll need to replace the freewheel . Cost about $20 .00 at any bike shop .

Will try that again. Thanks!

IF you have colder weather, the pawls in the mechanism might be hanging up because of thicker grease....

Shimano freehubs are indeed replaceable. OP, what model is your rear wheel?

Be careful spraying WD40 into freehubs, if you've got one. If it gets into the wheel bearing, it'll attack the grease.

It is cold here, but the problem existed in the summer too.

Don't know that right now, but I know it's a Specialized Hardrock that's about 7 years old. It's the one that has the twist grip shifters.

If you haven't replaced the chain then the problem is most likely not in the cassette or cogs on a freewheel. With index shifting if it is a little out of adjustment it can slip. The freewheel or freehub pawls can slip if they haven't been serviced in a while.

Have you adjusted your derailleur cables? A periodic skip while pedaling is often a sign of a derailleur out of adjustment. You may only notice it while pedaling had because frame flex is exacerbating the problem.

Step one for any chain skipping is to assess the chain and sprockets' wear condition. This is easily done with a 12" ruler (no great precision is needed).

Use a string around the lever to apply the rear rake and hold it locked. Pull the lower RD pulley back to put some tension in the Chain's lower loop, and measure 12" (24 links) of chain. Since the chain has 1/2" pitch each pin 1st through last should line up at the 1/2" marks, but wear at the pins allows the links to move apart more so the chain will appear stetched and what should be 12" will be slightly more. If your chain is stretched by more than 1/8" over 12", that's your problem, and you'll need a new chain and most likely a new cassette, and (bad news) possibly a new sprocket.

Anoter test is to use a small screwdriver to gently lift the chain away from the chainring at the halfway wrapped position (3 o'clock). You shouldn't be able to pull it away enough to see 1/4" of daylight under the chain. This test mixes chain and sprocket wear, so the only it confirms a sprocket problem is it's done with a new chain.

Is it possible to spray the freewheel (I've heard I might have a freehub) while the wheel is assembled on the bike? Where exactly would I spray?

not to interrupt the thread but I'm having the same issue, 71 supersport, the chain is slipping on the small ring gear, the teeth dont look worn, so it's possibly the chain, the freewheel is a really nice condition suntour I just put on, but I can actually see the chain slipping at the crank sprocket, the bike even had the original rear tire still on it, so this is possibly a 41 year old chain, any specific chain and I'm sure sure how to make sure I'm getting the correct length

Yes, you can flush a freewheel while it's on the bike, it's just a very messy process. Place the wheel flat on the floor (outside is best, and/or use a plastic drop cloth). Direct the spray at the gap between the turning outer body (sprockets) and stationary inner body. Spray and let it run in, helping by turning the sprockets. Repeat until you see it dripping out the back, and the sound changes. Spin the freewheel, allow to drain, then oil it the same way. Now begin the long process of wiping solvent and oil off the spokes and hub.

Note this method isn't usually suitable for freehub/cassette systems since it's likely to also flush grease from the axle bearings.





It's not whether your chain is too long or not, but whether it's too worn or not. Search "chain stretch" here on the forum or elsewhere on the net to learn how to measure the chain's wear.

Since I'm a novice at bike mechanics, I want to make sure I get this right. If the wheel is mounted on the bike and I have the wheel laying flat on the floor, which way will the bike be laying? Will the cassette be facing the ground, or upwards? I did spray it in the area you indicated in the past, but I had the bike upside down which may have caused it to not work.

for the cost of the chain, and the original condition of the bike, it was in terrible shape by the way, I'm going to make the logical assumption that the chain is toast. I haven t replaced a chain in probably 30 years so I'll have to search on how to install the links etc

You'd want the bike laying flat with the chain on the top. Before laying it down shift to a larger rear sprocket to get that chain out of the way, and you'll be spinning the wheel rather than the sprockets to get the motion needed to circulate the solvent.

As I said earlier, this is a messy process, doing it on the bike is messier yet.

As soon as you clear this hurdle, find a bike co-op, or a shop offering basic repair courses. Flats are common enough that you don't want toride beyond walking distance from home if you cannot fix a flat, which involves wheel removal and remounting. This is easy enough stuff to learn that I believe everyone over 10 years old should be able to do it.

I'll be doing it outside, so the mess to clean up will be minimal. The reason I'd do it with the wheel still on the bike is so that I can spin the wheel easier.

you can spin the freewheel much faster than the whole wheel.

can anyone tell me if a rear wheel sprocket/ring cog can be tightened? mine began slipping and now it will not turn the wheel. Joe

Please don't attach to old dead threads unless you are certain they are really pertinent. Better to just copy the url of the thread as a link in your new thread.

Is this a single speed rear with coaster brake?

Is it a freewheel or cassette on the back and only one cog is spinning? If so, which one?

If you are not sure whether freewheel or cassette you can post a pic to a site that hosts pics and link it to your post. If you have a google mail account then you should have photo hosting with them that you can share a link.



Oh.... welcome to the forums!