How to prevent chain falling off while pedalling?

[Tim Hall]

Also, avoid riding in the big chainring and biggest cog at the back (ie cross chaining) then dropping down to the little ring. This is more likely to cause the chain to come off inwards (I know from experience).

Edit: @boydj beat me to it ... just.

Note also that as long as you have a bit of momentum you can often put the chain back on just by pedalling gently and using the front mech. No need to stop and get oily fingers. This is easier with old fashioned friction shifters than brake lever shifters but it's entirely possible with both.

A pickup pin on the crank helps too, when the chain has overshot from the big ring.

 

[ColinJ]

Note also that as long as you have a bit of momentum you can often put the chain back on just by pedalling gently and using the front mech. No need to stop and get oily fingers. This is easier with old fashioned friction shifters than brake lever shifters but it's entirely possible with both.

It happened to me on this afternoon's ride!

I managed to ease the chain back on as described above.

Dropping the chain like that should be very rare if the bike is set up properly, but it can still happen from time to time. I have the endstops on my front mech set as tight in as I can, still be able to change between the rings and not get chain rub once the shift has happened but the chain overshifts 3 or 4 times a year.

It is important to react quickly and stop pedalling while you take a look and see if it is safe to try to ride the chain back on. I have had the chain get well stuck and any further pedalling would have snapped it.

 

[RichardB]

It happened to me yesterday, but with the rear mech. I was churning up a steep hill, dropped two gears to my lowest, and ended up pedalling fresh air. It's a good thing the MTB has a sloping top tube or I would be applying to join the Vienna Boys' Choir. The chain had overshifted and was jammed between the biggest sprocket and the spokes. I have the lower limit screw set pretty carefully, but obviously it needs a tweak. Half a turn backwards with the pedals had the chain in place again, and off I went.

 

[ColinJ]

It happened to me yesterday, but with the rear mech. I was churning up a steep hill, dropped two gears to my lowest, and ended up pedalling fresh air. It's a good thing the MTB has a sloping top tube or I would be applying to join the Vienna Boys' Choir. The chain had overshifted and was jammed between the biggest sprocket and the spokes. I have the lower limit screw set pretty carefully, but obviously it needs a tweak. Half a turn backwards with the pedals had the chain in place again, and off I went.

Take a very close look at the spokes to see if they were damaged by the chain. I had a spoke break on a forum ride from such damage. The rear wheel had a low spoke count so losing just one spoke made it go very out of true. I had to bodge*** the bike to get to Blackpool station then pay £13 to catch the train home.


*** I took the rear mudguard off and removed the rear brake blocks.

 

[fossyant]

I was cycling today, changed gears on the front chainring, and suddenly I felt no power in my pedal strokes. It turns out that the chain at the front end 'slipped' out of the cogs and onto the pedal bracket..

Big bit of advice to anyone. Listen to the gear change. If it sounds funny, something isn't right and don't start powering through the change. Stop and look. If you aren't mechanically minded, don't try and ride the bike through it, unless you know exactly what's causing it.

STOP and check.

Gear limiters take some fine tuning.

 

[RichardB]

Take a very close look at the spokes to see if they were damaged by the chain. I had a spoke break on a forum ride from such damage. The rear wheel had a low spoke count so losing just one spoke made it go very out of true. I had to bodge*** the bike to get to Blackpool station then pay £13 to catch the train home.


*** I took the rear mudguard off and removed the rear brake blocks.

Thanks for the heads-up, It was duly checked and pronounced good within five minutes of returning home. I am fairly mechanically sensitive, and while I admit the change was across two cogs and under some pressure, as soon as I felt it go slack I took all the weight off the pedals - hence the near miss with the top tube. But definitely a reason to go over the whole mechanism and tweak the adjustments before my next ride.

 

[mjr]

Gear limiters take some fine tuning.

Really? Tighten the limit until it won't shift into the edge cog and then gradually ease it back until it just does - what am I doing wrong? (Besides using nothing wider than a 7-speed rear )

 

[fossyant]

Really? Tighten the limit until it won't shift into the edge cog and then gradually ease it back until it just does - what am I doing wrong? (Besides using nothing wider than a 7-speed rear )

It's not a problem for me but many folk on here can't get it right.

 

[Jody]

Take a very close look at the spokes to see if they were damaged by the chain. .

Surely depends on wether the "dork disc" was removed.

 

[mjr]

Surely depends on wether the "dork disc" was removed.

Many spoke protectors would flex enough to allow spoke damage

 

[RichardB]

Surely depends on wether the "dork disc" was removed.

Not removed, because never there.