Bike chain slipping - help?

[janas19]

Hey AT guys. So I have an old but beloved Schwinn that I bought used off Craigslist for 80 bucks. When I bought it everything was working fine, but just a week later, the chain started to slip. It's only a 3 speed bike, so I imagine the gears are simple, but I don't know exactly how to diagnose what is wrong.

It only slips in first and second gear. When I have it in 3rd it rides fine.

Appreciate any advice!

 

[NutBucket]

I'm guessing this has a transmission in the rear hub? I'd say that's shot, not the chain itself.

 

[janas19]

The transmission's on the back wheel, yes. Is this a repairable issue or do I have replace it with a new one?

 

[NutBucket]

On the back wheel (derailleur) or in the hub?

 

[janas19]

On the back wheel (derailleur) or in the hub?

Sorry, in the hub. I'm not very familiar with bike terms. This bike is like 30 years old, so it's not the new technology. It doesn't have a derailleur. I've looked at it hard, and all I can see is a single sprocket on the rear hub, and a single sprocket on the pedal axis. The single sprocket confuses me? I thought there was supposed to be one sprocket per speed, ie, 3 speeds = 3 sprockets.

Thanks so much!

 

[Bignate603]

Sorry, in the hub. I'm not very familiar with bike terms. This bike is like 30 years old, so it's not the new technology. It doesn't have a derailleur. I've looked at it hard, and all I can see is a single sprocket on the rear hub, and a single sprocket on the pedal axis. The single sprocket confuses me? I thought there was supposed to be one sprocket per speed, ie, 3 speeds = 3 sprockets.

Thanks so much!

It's got all the gearing in the hub so you only have one sprocket. When it starts "slipping" (which I assume to mean that you're peddling but the power isn't getting to the back wheel) have you looked at the chain and sprocket to see if they are moving? If that sprocket on the back wheel is turning when you feel it slip then the problem is internal to the hub.

The hub may not be dead, sometimes things like the shifter get slightly out of adjustment so it will pop out of gear. From the sounds of it you're not horribly familiar with how to work on bikes so it will probably be worth taking it down to a local bike shop and having them tune it up. I prefer independent bike shops, they tend to be friendlier, more helpful, and cheaper for service.

 

[mechBgon]

This thread is worthless without pics!

Let's see a couple pics of your hub. It's most likely a Sturmey-Archer and probably just needs a cable adjustment, which is straightforward enough. Operators are standing by

 

[janas19]

It's got all the gearing in the hub so you only have one sprocket. When it starts "slipping" (which I assume to mean that you're peddling but the power isn't getting to the back wheel) have you looked at the chain and sprocket to see if they are moving? If that sprocket on the back wheel is turning when you feel it slip then the problem is internal to the hub.

The hub may not be dead, sometimes things like the shifter get slightly out of adjustment so it will pop out of gear. From the sounds of it you're not horribly familiar with how to work on bikes so it will probably be worth taking it down to a local bike shop and having them tune it up. I prefer independent bike shops, they tend to be friendlier, more helpful, and cheaper for service.

Holy hell Batman, so the gearing is INSIDE the hub?? ... Someone give this man a gold star!!!

Yeah I have done no further investigation other than feeling it slip. So I'll look at the sprocket like you suggested to see if it's moving.

YES I'm not too familiar with bikes, can you TELL? Lol.

 

[janas19]

This thread is worthless without pics!

Let's see a couple pics of your hub. It's most likely a Sturmey-Archer and probably just needs a cable adjustment, which is straightforward enough. Operators are standing by

Haha. I'll work on getting some pics up in the next 24 hours hopefully. Thanks.

 

[mpo]

It's probably a Sturmey-Archer 3-speed hub. Here are a couple sources to help you:
http://oldbikeblog.blogspot.com/2008/07/how-to-adjust-sturmey-archer-three.html
http://www.sheldonbrown.com/sturmey-archer_3-spd.html

 

[mechBgon]

Sure thing. In the meanwhile, this is the Cliff Notes version:

1. if you follow the cable from the shifter towards the hub, it probably has a housing stop clamped to the frame, and then the bare cable continues on and passes over a clamped-on pulley. Make sure both of those clamps are snug so they aren't sliding down the frame tube, or it'll keep going out of adjustment.

2. where the cable meets the hub, there's a tubular adjuster that threads onto a little threaded rod. The rod pulls a tiny chain that disappears into the end of the axle (on the variant I'm describing, that is). If you put the shifter into first gear, then use your finger to gently tug on the cable, the tiny chain should be able to move just a little bit, like 1 millimeter, in and out of the axle. If not, thread the tubular adjuster up and down the metal rod until you've got that slight movement in first gear.

One other prerequisite, and a caution: if the hub itself moves, this changes the effective adjustment on the cable, so you also want to ensure your axle nuts are snug. BUT DO NOT OVERTIGHTEN THEM, particularly the left one, because they're prone to stripping and they're hard to find replacements for.

 

[janas19]

Sure thing. In the meanwhile, this is the Cliff Notes version:

1. if you follow the cable from the shifter towards the hub, it probably has a housing stop clamped to the frame, and then the bare cable continues on and passes over a clamped-on pulley. Make sure both of those clamps are snug so they aren't sliding down the frame tube, or it'll keep going out of adjustment.

2. where the cable meets the hub, there's a tubular adjuster that threads onto a little threaded rod. The rod pulls a tiny chain that disappears into the end of the axle (on the variant I'm describing, that is). If you put the shifter into first gear, then use your finger to gently tug on the cable, the tiny chain should be able to move just a little bit, like 1 millimeter, in and out of the axle. If not, thread the tubular adjuster up and down the metal rod until you've got that slight movement in first gear.

One other prerequisite, and a caution: if the hub itself moves, this changes the effective adjustment on the cable, so you also want to ensure your axle nuts are snug. BUT DO NOT OVERTIGHTEN THEM, particularly the left one, because they're prone to stripping and they're hard to find replacements for.

This is super helpful. I see the tubular rod you are talking about. I'll have to look at it tomorrow because it's dark and I don't wrench at night, you know what I mean? Lol.

Thank you.

 

[janas19]

It's probably a Sturmey-Archer 3-speed hub. Here are a couple sources to help you:
http://oldbikeblog.blogspot.com/2008/07/how-to-adjust-sturmey-archer-three.html
http://www.sheldonbrown.com/sturmey-archer_3-spd.html

That's the one. Thanks so much mate!

 

[Dman8777]

I have a related question about my wife's bike. Her bike is 7 years old and uses the basic 3-speed hub gear as explained above. I'm familiar with derailers only, and have done a little research on hub gears but still don't understand them completely.

The problem is that the 3rd gear (overdrive) doesn't engage reliably. I've played with the cable but the problem seems to be a lack of tension inside the hub gear. It seems like there is a spring inside the hub that puts tension on the cable and in third gear, the cable needs to be pulled as far into the hub as possible. However, even with the cable completely loose, ie no tension on the spring inside, 3rd gear only engages 1 out of 5 times.

Does that make sense? Is there an easy solution to this?

 

[mechBgon]

What brand/model of hub does her bike use?

 

[MagnusTheBrewer]

Most three speed hub bikes have adjustments for the cable. Some are obvious on the outside of the gear changer and some require you open the gear changer up. Bikes are dead simple. Form follows function. The reason for adjusting the cable is to change the point in which the gear change happens. Most likely the cable has stretched. Tighten up cable and ride. If still slipping, tighten more. If different gear starts slipping or refuses to engage, back off. Or, you could just ask anyone who was 12 in the 50's.

 

[mechBgon]

The core concepts of most bicycle adjustments are simple, yeah, but the devil's in the details sometimes Compatibility questions can stump even my 20-year veteran co-workers. Ironically, I'm much more scared of disassembling internally-geared hubs than I am of electronic fly-by-wire drivetrains like this one: http://www.youtube.com/watch?v=sfx1pupmzf8 To each his own...

Dman8777, on recent-ish 3-speeds from the time period you're discussing, you set the shifter to a specific gear that's the "home" gear, then adjust the cable until you get a couple of indicators to line up visually with eachother. In the event it's the popular Shimano Nexus 3-speed,

1. loosen up the bolt on the rear of the bell crank pictured below, make sure it's all the way onto the axle nut, then snug the bolt down modestly. Don't overtorque it, doesn't take a lot of force.

2. put the shifter in 2nd gear and adjust the cable until that yellow mark is between the two yellow lines.

 

[janas19]

Most three speed hub bikes have adjustments for the cable. Some are obvious on the outside of the gear changer and some require you open the gear changer up. Bikes are dead simple. Form follows function. The reason for adjusting the cable is to change the point in which the gear change happens. Most likely the cable has stretched. Tighten up cable and ride. If still slipping, tighten more. If different gear starts slipping or refuses to engage, back off. Or, you could just ask anyone who was 12 in the 50's.

Good to know.

 

[Dman8777]

I'll have to check her bike when she gets home today. I have no idea what model it is, I didn't see any obvious branding and there is nothing visible on it to adjust outside of the cable tension.