Developed a fault whilst riding!

[Cut_in]

Something has broken or isn't quite right on my bike today whilst riding to work, I was stopped at traffic lights and as I went to peddle off I couldn't. The bike just peddled forward as if you were peddling backwards, If this makes sense? I got it going again, but all along my journey it just kept doing this. There was no sounds of anything breaking, the chain was on correctly and tension was fine.

[eileithyia]

Sounds like something is not working in the freewheel hub. Had this happen in the old days of 'screw on' blocks esp when dirt had got in on the mechanism, usually remedy to turn bike on side and run oil into the centre of the block until it was running out the otherside to help clean I thru. More recently a friend had a freewheel fail and had to scoot home, and a couple of weeks later same happened to me, there were a few occasions as I pulled away from lights where the pedals did not take up the slack straight away, fortunately most of my journey is was able to time my slow down and move away from junctions so I barely stopped, and after a couple of moments the freewheel would click back in.... until 3 miles from home when I got stopped at traffic lights and it failed completey.... a nice walk in snow...

Must admit a local cyclist did see me walking, assumed it was due to the snow, turned his car around and loaded me and bike into car for the final mile.....
But it does sound to me as though your freewheel is about to fail. sorry

[LollyKat]

This happened to me once with a screw-on freewheel. It was a frosty morning and some water must have got in and then frozen. Fortunately I wasn't far from a little general store and bought some oil to run in as eileithya describes. Lay the bike down with the chain underneath, and trickle oil in from the back.

If it is a cassette or 'freewheel' hub I don't know how you can get oil in without dismantling it.

[andrew_s]

assuming it's a Shimano cassette hub...
If it's a cassette hub, all you can do is to take the cassette and freehub body off and run WD40 into it (see here). If this works, you will have to add a bit of thin/light lubricant to ward off rust, and repeat when you service the bike next.
If the pawl spring has broken, it's either a new freehub body or a new hub (which may be cheaper), in which case take the freehub body off the new hub to save a wheel rebuild.
You need a special tool to get into the freehub, and these days it's a make the tool yourself job (there are 2 little notches in the rim of the main RHS bearing cup).

If it's a screw-on freewheel, you can open it up and service it using a pin spanner or punch, but it's a fiddly job if you take everything apart fully.
easier instructions

1: Remove the freewheel from the wheel. The ''upturned extractor tool in vice, and turn wheel anti-clockwise'' method works fine. Note that some freewheels (SunTour, Huret, Hero, cheap Chinese etc.) use two or four cut-outs on the end of the central core, rather than splines through it. For those, putting the axle through and clamping it up over the tool is a worthwhile precaution, to prevent the tool slipping out of the cut-outs and burring them off.
2: Clean off the exterior, particularly round the face of the lockring on the outer end of the freewheel, inside the top (smallest) cog. Also around the annular gap on the spoke side, between the central hub and the outer cog-carrier body.
3: With the tool in the vice, sticking up, 'mount' the freewheel on it, lockring upwards, and partially unscrew the lockring. Note that this is normally left hand thread, so unscrews CLOCK-WISE. Most lockrings have two small holes or dimples to turn with. It normally needs one or two sharp raps with a hammer on a small punch or screwdriver to start the thread undoing. DO NOT COMPLETELY UNSCREW THE LOCKRING. Leave a thread or two engaged; it keeps all those tiny balls, pawls, springs etc. in their proper place.
4: Flood the face of the lockring with petrol. Then spin the freewheel as the petrol drains down through the mechanism.
5: Do this 'flood and spin' many times. After the first couple of goes, the freewheel will start to feel 'gritty', and may even partially jam. This is dirt and grit flushing down through the gubbins. Keep going, and the freewheel will evantually start to spin more freely and smoothly. And the clicks from the freewheel pawls will start to sound louder and more distinct. Keep going with the 'flood and spin' until the juices run clear: the petrol coming out the bottom (spoke side) of the freewheel is no longer brown and gritty, but clean. By now, the freewheel should be spinning VERY easily; it's now effectively dry of gease/gung/dreck etc.
6: Put the freewheel - still lockring uppermost - in a warm place, for the petrol to evaporate off.
7: When completely dry, turn the freewheel over, so it is spoke-side-up. With your left hand, push the mechanism upwards inside the outer body as far as the lockring thread will allow. This will leave a small (1mm to 2mm) annular gap between the inner hub and the outer cog-carrier body. Using a grease injector (or the end of your finger, if you haven't got an injector), work clean grease into the annular gap all the way round. Try and get the grease as far in as possible.
8: Turn over the freewheel again, so it is again lockring-up. Finish unscrewing the lockring. This exposes the 30-odd bearing balls of the outer race. Make sure the lockring doesn't 'pick up' any of the balls as you lift it off.
9: Put 3-4 drops of oil onto the bearing balls AT ONE POINT ONLY. This oil will drain down and lubricate the pawls and pawl springs.
10. Put a filet of grease right round on top of the bearing balls. Add a filet of grease to the cone race - which you will find on the underside of the lockring.
11. Replace the lockring and screw it up (remember, ANTI-CLOCKWISE). Finish it with one or two sharp taps with a hammer and punch in one of the lockring's face dimples.
12. All done. You should now have a freewheel that turns with a smooth, greasy movement, and pawls that engage with a sharp click.
The whole procedure takes about 20-30 minutes (not including drying time). You don't have to handle all the tiny bearing balls. And the freewheel will carry on for another 10 years!

[drossall]

Club riders used to pour their coffee into frozen-up freewheels

[LollyKat]

I have read that a natural source of warm liquid was also sometimes used !

[Brucey]

simplest cure is to warm the freewheel, then purge the freewheel bearings with WD40 or similar. If it is ice inside or sticky grease, it'll help, so try that first.

What it won't do is fix broken pawls or pawl springs.

cheers

[Cut_in]

Thanks, i'm going to go try a few of the suggestions right now. I was actually thinking in was the cranks as I've never had a fault like this before.