Chain length

[Wayners]

24 speed bike.
Second hand.
I can't get biggest front and rear gears at the same time. My chain is definitely too short. Is this correct as not a gear I'd use?

Best I can do

 

[sjpt]

It's generally best to avoid biggest to biggest as the chain angle is too great and will cause wear and inefficiency. However, it is convenient sometimes to be able to get it, so best to have a slightly longer chain as long as it doesn't affect anything else badly.

 

[Wayners]

I just wondered how it should be.
I'm going to put rear hub on so I doubt I'll ever need the lowest gear but it don't seem to be running right in the first 4 gears. 1st I can't get. 2nd, 3rd and 4th the derailleur is not smooth.
I think something is not correct? I'll get a longer chain I think.

 

[Nealh]

Your chain length should be on big /big without going thru the derailleur then add two links extra on the overlap.

 

[chris_n]

Nealh beat me to it!
The biggest problem is that if you can try to select that gear then at some point you will. Whether you are distracted or caught out with a sudden steep incline you will push the lever all the way to bottom gear and snap the chain (no need to ask how I know). That bike only needs an extra 2 links, all you have to do then is ensure that when it is in small and small the chain doesn't rub on itself as it comes through the derailleur. If it does you need a derailleur with a longer cage to cope with the extremes or remove the small chainring as you probably won't use it anyway.

 

[Wayners]

On my other bike I followed RJ the bike guy video. He had a different approach to the 2 link rule and it's worked well.
I'll have a count though and see how many links I need with the 2 link rule.
I'm thinking the current chain is not the original one.
Also I think the clarks chains are the best. I binned the shimano chain with the supplied link. I ended up accidentally snapping chain trying to fit it. Difficult link to fit

 

[Bikes4two]

Definitely go for a long chain as has been said already, if you don't you will almost certainly at some stage attempt to shift into 'big to big' and end up with all sorts of problems.

I like KMC chains as they come with a 'quick link' (different sizes for different chains, e.g. 10s, 9s, 8s) and these links also work fine with Shimano chains too.

I always carry the used 'quick links' in my puncture repair outfit just in case I or a cycling buddy get a chain problem whilst out on the road.

Decathlon 9s chains are KMC chains repackage (KMC is stamped on the chain links) - I don't know about there other chains though.

 

[Nealh]

The risk isn't only snapping the chain but damaging the mech.

 

[Raboa]

Buy a different colour quick link, for example grey chain, gold quick link. This gives you a starting / finishing point when oiling the chain, makes the quick link easier to see and cheaper than a gold tooth.

 

[paxo22]

See these guides for optimum chain length. https://bike.bikegremlin.com/614/chain-length-sizing-for-bicycles-with-derailleurs/

Derailer Adjustment

Sheldon Browns guidelines apply to bikes with multiple chain-rings
On a single chain-ring bike allow 4 extra links. On my 7 speed Krieger that works out at 114 links. The origional 126 link chain was way to long.

 

[paxo22]

Buy a different colour quick link, for example grey chain, gold quick link. This gives you a starting / finishing point when oiling the chain, makes the quick link easier to see and cheaper than a gold tooth.

I simply put a short piece of light string around one of the wide links. It dosen't get caught on the deraileur or jockeys.

 

[Waspy]

You could always dump your front derailleur and shifter and 3 ring chainrings altogether and go for a single chainring setup.

It saves weight, simplifies things and removes those 'big cog to big chainring' woes.

Relatively cheap and easy job.

I have a rear hub motor and hardly ever use the bottom four gears. My chainring is 42 teeth.

42x11 is enough to stop me spinning out on a level surface at about 18-19mph (my max speed).

I would not fancy converting (hub drive) some of these very modern mountain bikes with the the tiny single chainrings and no room in the frame to fit a larger one

Notice I have attached the chainring inboard of the spider to improve my chainline, but then my BB spindle seems to be quite long.

Having said all that, although I have a mountain bike, I never go anywhere near any actual mountains.

 

[Peter.Bridge]

You could always dump your front derailleur and shifter and 3 ring chainrings altogether and go for a single chainring setup.

It saves weight, simplifies things and removes those 'big cog to big chainring' woes.

Relatively cheap and easy job.

I have a rear hub motor and hardly ever use the bottom four gears. My chainring is 42 teeth.

42x11 is enough to stop me spinning out on a level surface at about 18-19mph (my max speed).

I would not fancy converting (hub drive) some of these very modern mountain bikes with the the tiny single chainrings and no room in the frame to fit a larger one

Notice I have attached the chainring inboard of the spider to improve my chainline, but then my BB spindle seems to be quite long.

Having said all that, although I have a mountain bike, I never go anywhere near any actual mountains.

+1 - when I got the Woosh BBTS kit, it has a single chainring (I went for 48t, there was another option 44t, I think). I have 8 gears - think that is plenty on an electric bike (I can still get up 25% hills).