if i want to run a 1x 9 setup on my uncle john can i fit any single chainset to the front or will i get problems with the chain line? i was thinking about using an alfine chainset.

any chainset will do. why change chainset – just run a single ring, you might need shorter chainring bolts from charlie the bike monger.

HTH

Don't know about the UJ, but I just fitted a 36T ring onto an XT c/set with an Ultegra cassette on my HT and it's fine with a short cage mech and a few links out of the chain.
No problems with line or de-chaining, next stop SS 🙂

Do you need a front chain device to keep the chain in place?

Seen some setups with and without?

Guess it depends on what type of riding you intend to do?

Was thinking of using a Rohloff Chain Guide CC or Paul Comp chain keeper rather than the full on dh chain guides?

No chain device on mine – no rocks down my way but stays on over rooty bumps, down stairs and jey-drops 😉
I run a 12-27 cassette so can keep the chain length a fair bit shorter than if I was using a 34 large cog……

Am I also going to run into problems with a slack chain using a 11-34 cassette with a 32t chainring up front?

Use an unramped chainring and shorten the chain using the usual method of big / big + 2 links. Mine did not need a chain device set up like that but it was a bit marginal and it was mainly a commuter

Thanks TJ

Used a couple of setups,Hone cranks with 32T Shimano ring, On one bashring and Ngear jumpstop.

Now using 32T Renthal ring and MRPx1 chain device.

No problems with either setup but like to tinker

"Do you need a front chain device to keep the chain in place?
..
Guess it depends on what type of riding you intend to do?"

It does depend. On the road your may get away with just shortening the chain accordingly (round both boggest chainring/sprocket + 1 pair of links).
Make sure your chainline is aimed at the middle of the casette
You can use washers to space out the chainring bolts instead of buying short ones

You can use a single ring chainring (eg Thorn unramped, Onone SS etc etc), that are unramped and have deeper teeth to try to stop the chain falling off
You may find the single ring chainring is wide enough (the Thorn one is) to use the original chainring bolts so you don't need washers or short bolts

You can use just a front mech to stop the chain jumping postioned with the low stop in the right place

The Rohloff chainguide is £40-50 I think,
The MRP 1x (above) and ethirteen versions are both about £40

Many people use a bash ring on the outside (CRC have the FSA one for about £16) with something on the inside. Either an N-gear jump stop (above), an inner ring guide (blackspire do one, CRC sell it, fixes to the inner chainring bolt holes), or I use a zefal pump frame mount, fitted to the seattube (as I had one lying about) positioned so that it stops the chain from falling off the chainring. It only really works with a 34.9mm seattube though, anything smaller and the gap is too big (I've no pics I'm afraid)

I also found that with the chain shortened accordingly, a non shadow rear mech would run up against the chainstay and wouldn't shift too well. I've a long cage mech as its what I had and the bike sometimes gets put back to 3×9. With the shortened chain a longer mech is surely tensioning the chain more than a short one as the spring is under more tension, especially in the smaller sprockets?

Start with minimal parts and 'work up' as you encounter problems?

I run a 36t front ring (no pins or ramps) on a normal 3 ring chainset but used the shorter Middleburn chainring bolts. 11-34t rear cassette and a short cage X.0 rear mech. I run the chain fairly short so the rear mech holds a bit of tension in the chain. I had no problems with the chain skipping off, fitted a Paul Comp chain keeper though just to be sure.

anyone ever use the search on this forum? how many 1×9 threads have there been… all with the same info

oh well.. 😉 – what tyres for… lol

…

Running standard XT chainset with only middle ring and a short cage non shadow rear mech.
Have made chain guide similar to Ngear.
Works great on my P7.

Very nice setups.

thanks folks that helps a lot. i ll let you know how i get on.