Is there a way to prevent chains comming off often?

[Randombiker9]

So bassically recently my chains come off a few times whenever i switch gears. Like last week it happend 3 times (3 different days) this week it's only happend twice (Yesterday and today) It's easy to fix when it comes lose but is there a way of preventing it from happening? mine seems to come lose when i go up or down a gear or is this a sign it needs fixing or the gears aren't working properly?

 

[BoldonLad]

So bassically recently my chains come off a few times whenever i switch gears. Like last week it happend 3 times (3 different days) this week it's only happend twice (Yesterday and today) It's easy to fix when it comes lose but is there a way of preventing it from happening? mine seems to come lose when i go up or down a gear or is this a sign it needs fixing or the gears aren't working properly?

My first suspicion would be that either front and/or rear gear shifting mechanism is incorrectly adjusted.

 

[Sharky]

Don't think I can help, but for clarity, are you taking about gear changes at the front or rear or both?

 

[vickster]

Sounds like it needs adjusting..I've probably dropped my chain 5 times in 12,000 miles (across different bikes)...not counting the times it's come off when I have!

How many miles has the bike done - when was the cassette / chain last changed?

 

[slowmotion]

My guess is that the upper and lower limit screws on either the front or rear derailleur (or both) need a bit of adjustment. Get on Youtube and scrat around for derailleur adjustment.

 

[jefmcg]

If the chain is coming off the back, walk it to a bike shop and get it sorted. It could (jam the wheel/tear through your spokes) and have you flying over the handlebars.

If it's the front, yeah, you can probably fix it yourself. Certainly worth a try.

 

[DCLane]

Check the alignment and limit screws of the front derailleur.

Also, a Deda Dog Fang would help stop the chain coming off on the inside. Looks like this, works wonders:

 

[Randombiker9]

Sounds like it needs adjusting..I've probably dropped my chain 5 times in 12,000 miles (across different bikes)...not counting the times it's come off when I have!

How many miles has the bike done - when was the cassette / chain last changed?

the most miles i've done in a day is 10- 12 miles. Most of the time i ussually only do 8 miles intotal (4 each way)

I don't know when the casette/chain was last changed because my brother used to do all bike related mechanics but he's gone to uni.

 

[Randombiker9]

Don't think I can help, but for clarity, are you taking about gear changes at the front or rear or both?

happens either when i move down or up on the front gears on back gears so both.

 

[Profpointy]

As others have said above, first job is to adjust the limit screws. I dare say there are hundreds of you tube vids on this. Another possibility is if the chainrings are out of kilter or bent. I had a bent bottom bracket axle once and whatever I did to adjust them the chain got thrown off. It was quite obviously out of kilter once I'd noticed, but simply hadn't looked. Less likely than mere adjustment but possible.

Be warned, the limit screws do tend to be made of some special metal which is refined from cheese, and use and unusual jis screwdriver fitting so if you munge them up there is a lot to be said for replacing them with stainless allen screws.

 

[rrarider]

It would only be the limit screws if you were shifting to the smallest or largest sprocket. If it happens on intermediate changes, I'd suspect a stiff link.

 

[Sharky]

If your free hub is sticking and you momentarily stop pedaling, the chain keeps on rotating and unships.

Could be the cause?

 

[themosquitoking]

Check the alignment and limit screws of the front derailleur.

Also, a Deda Dog Fang would help stop the chain coming off on the inside. Looks like this, works wonders:
View attachment 380998

Comparing the look of yours to the original it looks like yours has seen some action.

 

[gazza1286]

Randombiker9: if you are serious about solving the problem yourself, my advice is to buy a cheap repair stand. Without such an investment, indexing and setting limit screws is a nightmare. A stand will pay for itself almost immediately. The best and most comprehensive YouTube videos on this subject are produced by Park Tools. Most others seem to overlook key areas.

 

[Ajax Bay]

bassically recently my chains come off a few times whenever i switch gears.

happens either when i move down or up on the front gears on back gears so both.

Does the chain come off at the front to the outside of the large chainring (ie towards the crank) or to the inside and gets stuck between the seat tube and the inner chainring, or both?
Does the chain come off at the rear to the outside of the smallest sprocket (cog) (ie towards the dropout) or to the inside and gets stuck between the spokes and the largest sprocket, or both?
When the front derailleur is pushed across to shift onto the large chainring, how many millimetres are there between the cage and the chainring teeth (ie how many mm would you have to drop the front derailleur to cause interference)?
https://www.parktool.com/blog/repair-help/front-derailleur-adjustment
https://www.parktool.com/blog/repair-help/rear-derailleur-adjustment
Patience is required.