I want a rohloff , chain and chainglider
But I’m totally bamboozled by the rear sprockets and chainrings
Does the chainglider only fit certain combinations and Certain brands?
Is there like a standard universal combination that is tried and tested that would be a good recommendation?
A Chainglider consists of two major and some minor parts. You don't need to worry about the minor parts as long as you choose the two major parts right. The two major parts are the sprocket cover and chainring cover, the latter having the runs of chain cover moulded with it as one piece.
There is a proprietary Chainglider dedicated Rohloff rear cover for the sprocket. It would be all right for Martin, who has experience of Chaingliders on several bikes, to mess around with the covers for Shimano or other hub gearboxes, but you, who don't yet know what's what in Chainglider land, would run the risk of scratching your expensive Rohloff HGB if you stray from the approved part. So buy the Chainglider sprocket cover made specifically for the Rohloff, of which there is only one, which takes all the approved sprockets. (Actually, there's another sprocket, but no one fitting out a touring bike would even consider it.) You can now choose between Rohloff sprockets with 15, 16 and 17 teeth.
Before you can choose the front Chainglider cover for the chainring, you must decide how many teeth the chainring will have, because there are three Chainglider front parts which
each suits only one tooth count, 38, 42 or 44 teeth. Chainring tooth count and Chainglider front part must be an absolutely precise match or the mismatch will look horrible.
The three front parts of the Hebie Chainglider for 38, 42 and 44 teeth are each duplicated in a short and long version. It's not a big deal because the runs of chain covers must be trimmed to length anyway where they join the sprocket cover, and there is some overlap, but with an extra-long bike (like my 2m+ Kranich, for instance) or an extra-short bike (Surly Karate Monkey, IIRC) it could matter. In practice all that is required is for the bike builder or assembler to measure from the centre of the pedal axle to the centre of the rear axle, and to order the long or the short front part of the Chainglider for his choice of teeth on the chainring accordingly by a code letter for the length on the part number.
At this point, having chosen the number of teeth but not yet chosen the precise chainring your will use, you run into another minor complication, which is that the Chainglider is made to take chainrings of a fixed thickness, thinner than many desirable aluminium chainrings, like the Thorn one. Many of us have solved this problem by buying the Surly stainless steel chainring, but you should inform yourself of whether there is a Surly tooth count for whichever spider you want to mount it to. It's less of a big deal than it sounds, because suitable cranksets are readily and cheaply available, and you probably have something that fits already.
Another consideration with the crankset, either what you have or new, is that the Rohloff spec requires a pretty strict adherence to the approved chainline, but this is easily solved with the right axle length in your bottom bracket or even a few spacers.
All this repays care but is no more difficult than decisions elsewhere about your bike, for instance choosing the bike from the Thorn list that suits your body measurements and riding style.
I were you, I would choose 38x16 teeth, which is the default choice for many upmarket European bikes. For the longest time, and perhaps still, Rohloffs came from the factory with a default 16T sprocket, so it is very common. And 38x16 is, as Martin has pointed out, close to 45x19. Also, a Surly stainless chainring is available in 38T with bolt patterns for common spiders. That makes 38x16 an easy choice for you. It is also a very common starter combination, including with riders here who've since moved on to more exotic transmission combinations on their Rohloff, some requiring surgery. I used 38x16 for years and was perfectly happy, and changed only because after heart surgery I fitted a central motor which required a deep-dished chainring to make the chainline.
The chain is the least of your problems right now. I consider the KMC X8 the best balance between cost and performance, and others here also like it, but other chains also have adherents, such as the Connex chains I used before I switched to KMC.
If you decide to proceed as outlined in this post, ask and we can look up part numbers for you. On this page are some tables I used to decide that I would take the default 38x16T Rohloff transmission from among those which fit the Chainglider:
http://coolmainpress.com/BICYCLINGHebieChainglider.htmlGood luck.
