or Connect
EpicSki › The Barking Bear Forums › Off-Season Sports & The Lighter Side › Cycling › Bicycle - Gears slipping?
New Posts  All Forums:Forum Nav:

Bicycle - Gears slipping?

post #1 of 40
Thread Starter 
I first noticed last fall, but put the 10 speed away for the winter before I had a chance to look into it. It happened again the first time I took that bike out this spring (my other bike got laid up with a broken shifter cable). It feels like if the chain is slipping for about 1/4 to 1/2 a rotation of the crank. At first I thought it was just that the derailer was between gears (old-fashioned not indexed), but on closer inspection it happens when everything seems lined up straight. It happens in any gear, but only when pushing hard on the pedals. It's also hard to catch it in the act as I don't want to be staring at my rear gear set while I'm riding along pedaling hard.

Any ideas?
post #2 of 40
Was the chain or the rear cogs replaced at any point recently? Chains and cogs wear each other down, but they remain compatible since they have equivalent wear patterns. What you're describing sounds like the classic symptoms of a new chain on old cogs -- they just don't "grip" each other.
post #3 of 40
Thread Starter 
No. As far as I know nothings been replaced, except the front tire (old one rotted off). I got the bike at a yard sale a couple of years ago.
post #4 of 40
I'd replace both the chain and cogs. Anything worth riding is worth having a decent drive train.

It could be one tight link on the chain. Go through it link by link. If one is stiff, work it side to side until it loosens up.
post #5 of 40
Quote:
Originally Posted by newfydog View Post
I'd replace both the chain and cogs. Anything worth riding is worth having a decent drive train.

It could be one tight link on the chain. Go through it link by link. If one is stiff, work it side to side until it loosens up.
Replace the chain and cogs and you may have to replace chainrings too (or maybe the crank depending on the model). Another possibility is a dying freehub body or freewheel.
post #6 of 40
Mine was slipping for a while, turns out it was the derailleur hanger that was bent.
post #7 of 40
post #8 of 40

10sp?

What bike?
post #9 of 40
Thread Starter 
I have the luxury of having two bikes for my "mountain biking". The first one, I inherited from my dad. It's a supercycle medalist (series II!). The second one is a Raleigh Grand Prix. As soon as I'm out of debt:, I'll be getting a proper trail bike.

It appears that that at the very least the chain is worn on the Grand Prix.
Thanks for the help.
post #10 of 40

Raleigh GP

Makes a fun fixie.
post #11 of 40
Quote:
Originally Posted by Ghost View Post
I first noticed last fall, but put the 10 speed away for the winter before I had a chance to look into it. It happened again the first time I took that bike out this spring (my other bike got laid up with a broken shifter cable). It feels like if the chain is slipping for about 1/4 to 1/2 a rotation of the crank. At first I thought it was just that the derailer was between gears (old-fashioned not indexed), but on closer inspection it happens when everything seems lined up straight. It happens in any gear, but only when pushing hard on the pedals. It's also hard to catch it in the act as I don't want to be staring at my rear gear set while I'm riding along pedaling hard.

Any ideas?

If you like to leave the bike in a higher gear and climb hills with it, you can stretch out part of the chain and it will skip exactly as you describe. I've had this happen and replacing the just the chain might be enough to fix it if it hasn't been stretched out long enough to damage the sprockets. Pull the chain off the bike and place sections of it on the large sprocket (it is easier to detect on a large sprocket), you should be able to find a section of the chain which doesn't quite fit the sprocket. Then see how the new chain fits before installing it or have someone with experience look at it. Of course if you know the pitch that the chain is supposed to be, you can simply take measurements.
post #12 of 40
Quote:
Originally Posted by Ski_the_Steep View Post
Of course if you know the pitch that the chain is supposed to be, you can simply take measurements.
Good point...the pitch should be 1/2". Put a ruler on a chain pin. If the pin near the 12 inch mark is more than 1/8" past it is time for a new one. You can check that without removing the chain.
post #13 of 40
It's a bike he got at a yard sale, the front tire was replaced due to dry rot, changing the chain will only cause more harm than good. The chainrings and cassette will be worn also, he either needs to replace everything or nothing, sounds like replacing nothing is his best option.
post #14 of 40
Agree that if the chain is skipping because it has stretched, the freewheel is probably shot too. My experience is that by the time it starts skipping, the chain is worn beyond the 1/8" per 12" that Newfy mentions and the cogs are worn too much to accept a new chain. Most bikes never get enough miles to even need a new chain from stretching, so this drivetrain might not be so far gone that it needs chainrings too. It takes a lot more to wear out the chainrings.
post #15 of 40
How about the freewheeler hub?
post #16 of 40
What is it? A bike of this vintage has a freewheel as opposed to a freehub. In either case, the hub should be OK, just the gears probably worn out.
post #17 of 40
It's been a long time since I've "wrenched" a bike. What's the difference?
post #18 of 40
Older bikes had the bearings and the ratcheting freewheeling parts in the freewheel (gear cluster) which screwed onto the hub. Newer wheels have all the moving parts included in the freehub (the hub which is laced with spokes to the rim). This makes the axle stronger because the load bearing part is wider. You only need to replace the actual gears (cogs). It is possible to take apart a freewheel and replace the cogs but I don't know where to get freewheel cogs. Generally the whole unit is replaced.
post #19 of 40
As usual time marches on. Thanks.
post #20 of 40
Quote:
Originally Posted by Whiteroom View Post
It's a bike he got at a yard sale, the front tire was replaced due to dry rot, changing the chain will only cause more harm than good. The chainrings and cassette will be worn also, he either needs to replace everything or nothing, sounds like replacing nothing is his best option.
spoken like a true retailer...don't fix it, buy a new bike! The only practical solution!


Chain rings are tough to wear out. They have a lot of teeth to distribute the wear. when they are worn the chain doesn't jump, it wraps around if not really well lubed. When I was a starving racer I could get away with using chainrings fives longer than cogs and ten times longer than a chain.

I think this bike has a chance for a continued and dignified life, with decent shifting. Stick with it!
post #21 of 40
Thread Starter 
Quote:
Originally Posted by newfydog View Post
spoken like a true retailer...don't fix it, buy a new bike! The only practical solution!


Chain rings are tough to wear out. They have a lot of teeth to distribute the wear. when they are worn the chain doesn't jump, it wraps around if not really well lubed. When I was a starving racer I could get away with using chainrings fives longer than cogs and ten times longer than a chain.

I think this bike has a chance for a continued and dignified life, with decent shifting. Stick with it!
You post this just when I was about to relegate it to donor-cycle status. The other bike just lost a shifter cable, and has separating tires, poor tape on the bars and rims that are dented (I guess I'm not supposed to go down rocky trails at 30 mph on road wheels) .

On the Raliegh, The steering seems a little weird and the chain is stretched; I measured it. I was debating which of the two bikes to keep up. Neither are worth a lot of money. They are both antique road bikes and appear very similar in construction (steel frame similar welds and geometry). I'm thinking if the chain is worn, probably the rest is too. Any money I put into it could be going towards a mountain bike instead.
post #22 of 40
Good choice. whiteroom was right too, I just was feeling nasty.

There are some ebay bargains on mountain bikes which don't have disk brakes. Not that disk brakes aren't great, but anyone on a budget ought to look around at what is being unloaded by people who just have that need to upgrade.
post #23 of 40
Spoken like a man who can't see the forest because of the trees...

You are 100% right that his bike can be fixed up and ridden long into the future. Any bike can be maintained and used indefinitely...that's the beautiful, magical thing about the bicycle.

If you stay on top of maintanance and change your chain every 1000 miles you may never have to change chainrings. If you don't keep on top everything wears out, when that happens the only solutrion is replacing the worn parts, all of the worn parts.

The reality is that it would be very odd for someone who bought a bike at a yardsale to spend the $80 to $100 it would take to give the bike a 'continued dignified life'. Ghost is an odd dude, maybe he will. Most wouldn't.
post #24 of 40
Oops...just saw the other two posts. Sorry Newfy, I was feeling nasty also.
post #25 of 40
Quote:
Originally Posted by Whiteroom View Post
Most wouldn't.


Dibs on the Mafac centerpulls.
post #26 of 40
Quote:
Originally Posted by comprex View Post
Dibs on the Mafac centerpulls.
Are you crazy?

Read an article on the Paris Brest Paris ride years ago, where a participant was describing riding all night. "the squeal of Mafac brakes alerted us to upcoming descents. If the French had been using Campy brakes we would have died"
post #27 of 40

I was being only half serious, but

They're all right. Just different quirks.

Salmon pads + adjusted straddle cable and I like them over the copy cat DiaCompes for fender fits & single hole forks. Good feel with inline 'cross levers.

There was a DA version at one point, I think, but those don't show up on yard sale Raleigh GPs.
post #28 of 40
Quote:
Originally Posted by SLATZ View Post
How about the freewheeler hub?
IMO this is probably the cause. The clue is that you said a 1/4 to 1/2 rotation jump. Worn cogs/chain cause much less of a jump. Time for a rebuild of the rear hub/freewheel.
post #29 of 40
Thread Starter 
Well I decided the Raliegh was worth making a road bike out of. I'll keep the heavier Supercycle for the trails (I'll get more exercise that way).

Upon investigation the chain was worn, and had one stiff link. It is soaking in oil. But I found that when I have it in 1st and have all my weight on the front pedal and am pulling up on the handlebars with a force about equal to my weight, the bike decides to shift into second gear:. Why is it doing this?

Also I think that I should be able to raise the bars a bit, by loosening the nut that goes through the stem. I"ve loosened it, but the bars won't come up. There is directly beneath this a large bolt or locknut that will not turn, followed by a holder for the cables and then another large bolt that does turn, but turning it does not make the stem any easier to lift.

Anybody got a schematic, so I don't break the thing?
post #30 of 40
Quote:
Originally Posted by Ghost View Post

Also I think that I should be able to raise the bars a bit, by loosening the nut that goes through the stem. I"ve loosened it, but the bars won't come up. There is directly beneath this a large bolt or locknut that will not turn, followed by a holder for the cables and then another large bolt that does turn, but turning it does not make the stem any easier to lift.
The old style-quill-stem, you described has a wedge that is connected to that bolt in the top of the stem. When you tighten that bolt it causes the wedge to dig into the fork steerer.

First thing you need to do is unscrew that bolt about 3 to 5 mm. Spray a little WD40 into the bolt hole and around the stem so it goes inside the steerer tube.

Next take a hammer. A framing hammer will do. Grab a short 2x4. Place the 2x4 on the bolt and hit the board with the hammer with moderate force. That should break the wedge free and the stem should move. Repeat as necessary. Do not raise the stem higher than the limit line.

That'll be $25

Now as to the large nut you loosened, return it to its original position or your headset adjustment will be too tight/loose.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Cycling
EpicSki › The Barking Bear Forums › Off-Season Sports & The Lighter Side › Cycling › Bicycle - Gears slipping?