Thinking of running a single front chain ring because (a)it might add a bit more of a challenge to my local routes and (b)I'm bored.

Set up would be either an XTR shifter/deraileur with 100s of miles on it or a sram X9/Gripshift with about 50 miles on it.
Either better than the other for this? Only difference that comes to mind is the lack of the b-tension adjust system on the X9. The chainring to be used is a Blackspire DH, so no shifting ramps etc.

The other factor here is would I need a chain guide? Riding is wheels on the ground mostly. Only when I'm really brave feeling I'll go to maybe a full 3 feet of drop. Plus I will be using a bashring.

Thanks
Dave

would've thought you need some sort of guide – the front mech works as a guide on a normal set up – DMR do this or just use your front mech & set it up to always be on the middle ring.

I run an XTR short cage mech, XT cassette (11-34) and 36t RF team ring and Blackspire stinger. I suggest at least a stinger because the chain will bounce. If you have ISCG tabs then run a guide but I though that was over kill and it adds weight. I have never dropped a chain.

You might get away with this

N Stop Chain Guide

I used to use one on my 1 x 9 set up, it took a bit of modding but it stopped the chain going inwards and had the added benefit of being easy to clean

I dropped the chain every 50m when I ran 1×9 and had a stinger-type device, did my head in. I had an unramped ring too. I put a full MRP chain guide on afterwards.

Ran that for about a year, then couldn't think why I was running 1×9 so put a granny on for an Alps trip and will leave it on there.

What are your reasons for using it for xc? Just some simplicity? That was mine at the beginning but the full chain guide pretty much negated that benefit!

It's getting increasingly popular, but you do need some sort of guide certainly, think I've seen some people using a really slimmed down MRP jobby.

i'm running a 1×9 with a n gear jump stop with no problems with a bash ring atlas crank

Yes, even a dog fang with a very light bash guard would work.

I pretty much only use the middle ring for off-road riding. I think I would like a 1×10. Lovely.

bashring an n-gear is bang on. ime

I just used an old MRP back plate and rollers that I got off eBay for not much dosh. I then got a chap that has a milling machine at work to mill the slots down so that it would be OK for a 32 ring. Works fine.

How do you measure the chain for a 1 x 9 setup?

will shorten the life of your chain, as will be inflicting more extreme angles on it for a greater amount of time.

(compared to if your using your triple set up properly at least)

if im going to be in the bottom 3 sprockets and middle ring for any great length of time, your better off in granny:3-5, to reduce the chain angle.

not many people bother though, hence the "10×2" XX thing (though in all faireness, if its specifically a double setup, the rings will have been realigned!)

N Gear jump stop and Bashguard work absolutely perfectly and does not add much weight like one of those cumbersome chunky MRP things.

Been running mine for nearly a year now and am still on the same chain, cassette and chain ring. The amount of time I spend on the top sprocket or bottom sprocket of the cassette is probably about 10-20 seconds each time so not much extra wear really, certainly nothing to worry about. 1×9 is ace.

Kev

"Blackspire DH, so no shifting ramps etc."
It depends on the riding and how well the unramped chainring holds the chain as to whether you need any sort of chain device.
I ran a thorn unramped chainring (from SJS, twas cheapish – I know at least one of the S/S on-one ones work too), without anythign for quite a while without a problem. General XC and anything upto the 'lumpiness' of sherwood pines caused no problems whatsoever.

When I started to try it on steps/stairs and more rooty/rocky stuff it did start to fall off a few times a ride

I've now got a plastic FSA bashguard (I think they're £14 from CRC (inc. longer chainring bolts – the 32T one is big enough to guide a 34T ring too) and one of those mounts for a 'classic' zefal style pumps (just pointing toward the chainring where the chain is, it phyically stops the chain from coming off. An N-gear jump stop as mentioned above would do a better job, but it costs and weighs more, I can't seem to find them that readily available and I had the pump bracket lying around already
I'll get some pics up if you want

"How do you measure the chain for a 1 x 9 setup? "
Easy, same as you would for a 3×9. Wrap the chain round your 2 biggest rings/sprockets (the 32 or 34 on the back and your front ring), but not through the mech + one pair of links overlap [with a 32 or 34T front ring you'll be taking 3 pairs of links out from a typical triple setup]

"will shorten the life of your chain"
But you won't be shelling out for granny rings or expensive outer rings. Plus your unramped 'middle' ring will have wider, fatter teeth that don't wear out as quickly, and because its unramped, is undirectional, so you can flip it round and use the other side of the teeth

"What are your reasons for using it for xc?"
2-1 uphill stops you form being too lazy andf droppping to 1-1 when it gets steep/long. 2-9 on the road forces you to spin. Both things I don't do on my main bike. It gives me a reason to take the 1×9 HT as an attempt to force me to try uphill and in an attempt to get better at spinning
Either that or some riding simply doesn't need any more gears than a 1×9 setup, so why carry around the extra 1lb in weight. Front mechs bung up in slop