Chainline question

So I've just built up a new bike, most components are new, a couple of second hand bits, but all of the drive chain is straight out of the box. And it's noisy and gritty as hell!

I have a Stronglight 48T Comp 144 at the front, a generic 18T sprocket at the back and a Sram P1 chain. All of them are 1/2 by 1/8. The bottom bracket is a brand new Miche Primato Track 107mm and the rear wheel is new (System Ex hub built on to a H Son Plus rim).

So I checked the chainline and it's a couple of mm out. I assume that's the problem but I wanted to ask why it would be out in the first place. My rear spacing is a touch under 42mm. And at the front it is just over 44mm.

The crankset recommended using a 107mm BB for a 42mm chainline (planetx.co.uk/i/q/CSSTTR2K/st­ronglight-track-2000-crankset) and I am using a Miche 107mm. So is it because I am crossing brands? Or is it common to run into this kind of issue? Finally how should I resolve it? The cranks are fully tightened on to the BB, which is itself fully tightened. Would you recommend using shims at the back, getting a different BB or something else?

Thanks.

How old is the Miche BB. They were ISO taper at one point but switched to JIS taper in the last year or two (maybe earlier than that). The old ISO taper BB's if I am not mistaken have adjustable cups. The newers don't. A stronglight chainset will be for JIS taper BB's.

A shim on the rear hub could sort the problem. It is more likely to be poor tolerances on the tapers on the chainset and BB.

The hub being off though is poor though.

Hey Cycleclinic, thanks for the reply.

This is the BB I ordered http://www.wiggle.co.uk/miche-primato-track-bottom-bracket/?sku=5360331215, I'm not sure if that is ISO or JIS taper. I don't have a campagnolo BB tool so I walked it to my lbs to get it fitted and didn't pay much attention. In the QandA on wiggle for the BB it says the cups are adjustable, so that may mean it's the ISO taper right? But then perhaps I could adjust them (at the lbs) to get the right chain line?

I just spent about an hour trying to manufacture a shim from some old store cards, but it seems the sprocket is greedy and even though there was plenty of thread showing the sprocket slipped under stress straight away. I reduced the shims to about 1.5mm and it did the same thing.

I mean if ordering a different BB would solve the problem then I am happy enough to do that, they're one of the cheaper components anyway. If that is the best route to go then should I get the stronglight BB and assume it's compatible?

Frustrating part of this is I just moved to Plymouth and this is the only bike I brought so I've been walking for the past week or so, which I'm not used to at all!