an old singlespeed chestnut

[lewis1641]

chain tension!

i think the tension is too great on my khs. is there a scientific way of knowing? the last thinkk i want is the chain to come off but i also dont want to wear stuff out prematurely or make riding harder than necessary.

i have just bought a halflink chain too so hoping to do away with a tensioner altogether if i can.

as the khs is, if i spin the pedals backk with reasonable force, i get about one rotation of the crank and the chain is very tight but it has never slipped.

 

[orange71]

I reckon on about 3/4" up/down movement in the chain at mid point between BB and rear axle.

 

[perry]

Tension isn't as important as chainline .

Take the chain off and run a straight edge from the sprocket to chainring to check .

I'll never use a halflink chain , It'll just stretch and ruin the rings .

Keep the tensioner , it might not look as good but it's the right thing to do , I use one that mounts to the bottom bracket on the Kona and its much better than one hanging from the mech hanger .

 

[lewis1641]

are the halflink chains really that bad? hope not! is it due to the thing on sheldon browns site where a standard chain and even numbered ring and sprocket don't wear?

chain line is bang on thanks to your previous advice perry.

funny you should mention the bottom bracket mounted tensioner as i have just picked one up.

the fleet is all change soon and the khs is going geared and the lava dome will be single speed so i'll fit it to that.

 

[perry]

Id leave it as is for the moment then , if the chainline is within a mm It'll have to be very slack for it to come off and even then you will have to pedal damn hard over very rough ground at an angle for the chain to loop off the sprocket

A tensioner on the bottom bracket is much better , taking the wheel out is a doddle , it's easy to adjust tension as stuff wears and the only thing thats wrong with it is the dirt clinging to it , but thats the same as one hanging off the rear of the bike anyway .

Half link chains are designed for bmx where grinding along a wall will pull apart a normal chain as it catches the outer plates , the half links will just rub along , kinda like fish scales . They will very quickly stretch as the links are angled and pull .

 

[lewis1641]

Half link chains are designed for bmx where grinding along a wall will pull apart a normal chain as it catches the outer plates , the half links will just rub along , kinda like fish scales . They will very quickly stretch as the links are angled and pull .

i must be a fashion victim - they looik awesome!

i am going to have to fit it now i have bought it though - cant be wasting money.

one side is totally flat and the other has a round bit at each rivit. i take it the flat part goes on the outside and the bumpy on the inside?

 

[MJN]

Bin your frame and get a ss specific one with either horizontal dropouts or eccentric bb,problem solved
I would worry about a slack chain as I've had chains come off on my ss and it took a while for the pain to subside
If its too tight you can feel it binding,the magic ratio seems to work for some people but I've always found chain stretch renders it useless after about 20 miles.

 

[lewis1641]

I was just thinking to myself this evening i have 2 kona frames to sell, that should be enough to get me a single speed on one frame new or something a bit better but used.

 

[jimihendrix]

If its too tight you can feel it binding,the magic ratio seems to work for some people but I've always found chain stretch renders it useless after about 20 miles.

I've been lucky with my E3, using a standard Shimano chain with 32-16, a new chain is very slightly tight but perfect after a couple of rides (about 20 miles) so it seems to me to run a magic ratio you need to have a new chain tight to allow for stretch, the pedals should spin two complete revolutions when spun backwards when the tesion is right, i change the chain every couple of months, never had one snap, slip or fall off.

 

[MJN]

Your cranks may spin 2 revs with the correct tension but that relys on the bb you use,I'm on hollowtech 2's so that's not gonna happen,they won't spin 2 revs without a chain on!Good tip otherwise though