Keeping a chain on a single-ring

[mattc]

... that has a 8-spd derailleur at the back (just to be clear!)

Not sure I've ever owned a bike like this one - as a yoof I jumped straight from BMXs to "proper" used road-bikes sourced by my resourceful papa.

Anyways, it does suffer from occasional chain-ship, when shifting gears. What are general thoughts on affordable remedies for this?

I'm quite tempted to carry small hooky-thing in a bag to keep the dirt off other belongings! All it needs is a small screw-driver, but there is probably an optimum shape for such a widget ...

[Ian H]

A narrow-wide chainring is the usual solution.  An older way is to use a front mech fixed with the limit screws and perhaps squeezed a little.

[PaulF]

You need a gusset, lil chap.   Seriously great piece of kit

https://www.leisurelakesbikes.com/29747/products/gusset-lil-chap-chain-device.aspx


I’ve used one with a 10 speed rear with no problem.

[Gattopardo]

Is it slipping off the front?

I had this issue, changed the chain ring to a single speed ring.  Rings for double and tripple are ramped to allow the chain an easier change but can cause problems on this kind of set up.

[PaulF]

If you’re going as far as changing the chainring then go for a narrow wide as Ian H says but a chain device may be cheaper.

[fuaran]

A Deda Dog Fang on the inside could help. https://www.chainreactioncycles.com/deda-elementi-dog-fang-chain-catcher-/rp-prod84217

Plus a bashguard on the outside.

[Brucey]

if you don't fancy a NW chainring (availability, cost, or you want an odd number of teeth)…..

- a 3/32" chainring meant for fixed gear works better than one for a double-ring derailleur setup, because the teeth are full height.

- a chain with cambered inner side plates helps the chain stay on (not all 8s derailleur chains are equal in this respect)

- if you take a 1/8" fixed gear chainring you can file the teeth so that they fit the chain (i.e. are about 2.2 to 2.3mm wide, which is wider than a typical 3/32" chainring; they can taper slightly too) and the chain will stay on better than with a 3/32" chainring.  A potential downside is that if the clearance is too small and there is too much dirt, the chain may start to bind on the teeth (so give chainsuck type symptoms).  This approach works really well on a road bike with mudguards though, and the chainring is really hard-wearing because it is wider than anything else you can use with that chain.

BTW a clutch-type RD helps too.

cheers

[hubner]

I find the chain only came off when changing gear going over a big bump and that was many years ago. But the ring's from the pre-indexed era and it's quite worn now.

[mattc]

Thanks everyone! A nice summary of the options 

I'm sure one of these will prove suitable ...

[trekker12]

I rebuilt my winter commuter as a 1x9 last year. The cheapest solution was to leave the front derailleur fitted as above with the limit stop out as far as it will go. There's no chain rub and it hasn't dropped off since.

[fruitcake]

My 1 x 8 folding bike deals with this using a dog fang and a chainring guard.

On my 1 x 7 MTB I've fitted a front derailleur as a chain catcher. I figure that gives gives me the option of going 2 x 7 in future.
 

[rogerzilla]

These work: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F153234153492

I had to fit one to the Moulton after it dropped the chain a couple of times.  It's a 1 x 9.