Can I put the outer 53t ring in the inner position for a 41mm chainline or do I have to use the 39t inner ring?

You can use either ring, just make sure you're using single speed chainring bolts. 53 is a little steep, though.

Putting the 53t chainring on the inner position of a road double might give you chainstay clearance issues, depending on the frame.

But in general, the chainline of a road double (measured in between the two chainrings) is 43.5. Given a 5mm chainring spacing, this puts the inner chainring position at 41mm, which will line up with your track hubs 41mm standard chainline. Or it'll be close enough.

I use a Campy square taper road crank on the appropriate (111mm) Campy BB, with a Miche 1/8" ring in the outer position. I also have a 1mm spacer behind my cog. Rear hub is a Cance Creek 120mm, which I assume uses the typical chainline.

The resulting chainline is perfect, and the crankset looks a lot cleaner than with the ring on the inside.

YMMV.

Cool... thanks guys. Found a pretty good deal on some FSA carbon road cranks. I think I might do it.

watch the carbon FSA cranks. If it is a three piece aka (spider and crank arm are separate) the spider can start to slip if used on a fg. I have the carbon track pro and I am dealing with the spider slipping on the crank arm after 300 miles.

If that's actually happening to your cranks, you have a bad set. It has nothing to do with their use on a fixed gear bike.

Eh, while it's true that he probably has a bad set, it's not like there aren't unique things happening to the cranks on a fixed gear.

A road bike crank only ever experiences tangential force in one specific direction, and this is not reversible or subject to assembly error. It's not inconceivable that a manufacturer could design cranks to be stiffer in one direction than the other, and I'd even say it would be smart.

Whether or not FSA has done that, I doubt it. But it wouldn't be illogical if they did.

I've seen a number of carbon FSA cranks come apart on road and cross bikes under "normal" use. I'd stay away from them period.

I'm looking at buying the Carbon Pro Team Issue. They're the newer design where the arms and spider are not serparate. They seem to get good reviews.