Custom how?

I've bought literally dozens of chainrings off eBay, both new/current and NOS/vintage, in standard mainstream sizes and oddball niche specs.

Just more teeth. Ultegra max 53, Dura-Ace 55 max for fair amount of money. Have some downhill races where people run 56-60. I've never used Ebay and not sure i could buy the proper thing w/o getting screwed, not exactly the 'wrench' type. SC 4 bolt assymetric 110 BCD, 11 speed. I've seen custom made online but not sure which sites folks have used with good service/outcome. Thanks.

I ordered one of the ARC TT chainrings in 58T from Aerocoach UK, supposedly it shipped this week. They have a "custom" option where they can drill the rings for Shimano 4-bolt compatibility (I needed this).

Some things to note about the ARC TT chainrings:

1) They're carbon fiber, so not cheap (although cheaper than Shimano Dura-Ace).
2) They're designed to be run 1x, shifting to small chainring with the ARC installed could damage the teeth.
3) They're non-round, though it's supposed to be pretty subtle.

The fact that it's CF and 1x means it will be a race-day only chain-ring for me, will keep my 55T on during the off-season and switch to the ARC just before competing. I'm not too worried about the asymmetry, friend of mine who already has one says it's so subtle he doesn't even notice.

I ordered mine in China. I ordered a 130BCD 17% oval 48T narrow wide aero-style for €55 including shipping.

http://s.aliexpress.com/fmeUVbIz