I’m upgrading an old Giant Trance 3. (2006/7, I think) as a winter hack and am unsure on the best approach.

Among other things I’m upgrading to:
SLX M660 crank and bottom bracket
Raceface 30/32t narrowwide chainring

Questions are:
What spacers do I fit to either side of the bottom bracket, shell measures 68mm?
Do I need spacers if I fit a 30t n/w chainring to the M660 or do I just fit it direct on inside or outside face of the 104 bcd spider?
Any experience with the crank arms clashing with the chain on a 30t?

Any help/advise would be greatly appreciated!!!

Shouldn’t need any spacers for the crank. Just fit to the middle ring of the spider. I don’t know about that crank but when I fitted a single ring to a triple I fitted it to the inside for the right chain line, but I did find I had to file down the spider to get the chainring on. Something odd about a single ring. I guess because they’re designed for single ring spiders really. That was pre NW days though, just plain old single ring.

Can’t see why the crank arm / chain would have an issue with a 30t.

Though I’d suggest 30t is a little small, unless you’re not bothered about top end spinning out. Most people I know run 32, 34 and a few even 36.

If you went for a SRAM crank you can replace the spider with a single ring spider or get a spiderless / direct mount NW ring.