What are the pros and cons?

I’d go for push up. Used to get chain slip on my old one when out of the saddle with a push down type, but fine with a push up. Makes getting the wheel out a tiny bit more difficult, But spot on really

Push up, push down isnt nice because your chain will slip unexpectedly.

Go for an on-one or a gusset. The sprung type ones are a faff.

Also, buy a half link from alans bmx, then you get get your chain as tight as poss (unless it is already) so you can ‘push up’

If your chain is too slck you cant do push ups

just to add, push down is usually fine as long as you use a larger sproket like 18T as there is more chain and cog contact
push up efectivley ads chain/cog contact and wrap around, push down reduces it

as mentioned push up doesnt always work if theres too much chain slack (like on my setup)

I have push down, 34/16. No slip problems even over rough stuff. The difference in wrap circumference with push up or down is minute, especially if you have a fairly tight chain already – like 5 or 6 degrees difference, personally cant see it making a difference but others seem to think so from experience so I bow to their knowledge!

Your right, If you have a tight chain then push down aint much of a prob.

Its just on alot of bikes, your chain is often a tad too tight to get it to go onto the chainrings, which means you have to add a link making it far to slack, so you have to push down. Then problems occur.

with a slack chain (mine) with a poor push down tensioner it does make a difference, mine slips with a 16t surley but is flawless with 18t, 17t is ok unless smashing it up a steep hill

is an ebay bargin bucket sprung push down tensioner, mr control type at less than £10

would like a rohloff one but cant justify the cost

Des – I’ve got a couple of different tensioners cluttering up the garage if you want to experiment.

on one doofer spring loaded pushing down
same as them mr control thingys

Thanks for the comments folks (and the offer Geoff), very helpful.

I’ve had various types of ss frames over the years and also used an eccentric eno hub on non ss frames but never used a tensioner. Might need to give it a go on my old Kona frame while waiting for Mike at Dialled Bikes to get the Love/Hate frames available again in the Spring.

I was wondering why a man of your ss experience had to ask such a question..
BTW Konas usaually have a magic ratio 34:17 IIRC but it was some years ago when I had one!