Noob question on chain tension

[B164D]

Hi - I'm 57 and recently returned to cycling on an old Phillips Premiere 12 speed racer - the doctor said move more and drink less Anyway the down-tube shifter brazing failed converting it to a 2 speed and I've taken it to a SS with a gentle 42/18 for my daily commute (with hills) . I've not been able (yet) to get the chain really tight - aesthetically this looks poor but providing it doesn't jump I can't see a problem. My question is why do folk try and get a really tight chain - surely that increases friction - or is it a fixie thing?
Cheers!

 

[B164D]

Thanks Adrian - all is clear now.

I'm using the existing block but will get a simple single speed freewheel in due course once I'm sure of the ratio. The reduced friction from not having a derailleur is quite noticeable and I like the simplicity of it all but don't think I'll go fixed wheel so I'll stop worrying about chain tension.

 

[biggs682]

or once you know what size cog on back get lbs to supply a freewheel in that size and redish the rear wheel to give you a proper chainline , simples and easy

 

[Ian H]

You can overdo the tightness and quickly destroy wheel bearings, even bottom bracket bearings, and of course, chains and cogs. The old rule was half an inch up and down of 'spring' (easy movement but not quite slackness) at the chain mid-point. Bear in mind that you'll often find that chain tension varies as it runs.

 

[SportMonkey]

I find if it's too loose on singlespeed the chain starts skipping. Owing to the way my SS works I move it out on the adjusters by a half turn every 150 miles.

 

[B164D]

Thanks for all the advice. After deciding 42/18 was good, lbs supplied a new wheel since old axle was bent and spokes very slack.
The result is below...

and the chain alignment doesn't look too bad

Just tried it out and seems good - to the point that come Xmas and the Triban becomes mine, this will continue to be used as my "Winter Wheels" for inclement weather.