and make it into a low maintenance commuter.

What parts do I need (its a standard dropout 456 old skool blue one, with a pro2 rear hub)

what is the best gear ratio?

dasnut

You’ll need a SS spacer kit – I’ve got a DMR felly right here for £10 posted to your door?

Depends on how flat your commute is for ratio…

commute is a big chunk of tow path, but a couple of road climbs (short but steepish)

do I need a new chain? (half link job) or do I use a tensioner?

please reserve that kit for me Mussed once I fully understand all this jiggery pokery then I may well have it….

I would go with a chain tensioner

You might need smaller chain ring bolts.

You should be fine with the original chain though

Is your middle ring a 32T, if so might be worth going up a bit to 38-42t with a 16t rear.

i have

bontrager singlespeed cranks with 38t unramped chainring, with bashguard. 170mm arms. Square taper. also have the 68mm sq.taper BB.

i also have Hope rear cassette spacer set in polished silver.

and new Groove armada rear cogs in 16t and 17t.

if interested my email is in my profile.

36 x 16 sounds just right for you.
32 x 16 makes you look like a hamster on the road.

Think my front is a 34 (34\24 setup at the moment) – how does 34×16 sound?

I have a bashguard which will be staying so I won’t need different chainring bolts

can I do without a tensioner if I use a half link?

mudsux what does the hope spacer kit consist of?

can I do without a tensioner if I use a half link?

probably not. it’s so much pfaff to get the magic ratio – when really what you’re seeking is a suitable ratio.