I'm going to enter my first race in about a month, and that has me examining my bike with a critical eye.
The bike started life as a 2007 Giant Yukon HT, and as I have been running up against the limits of the bike as bought, I have been upgrading it.
So the undamped Suntour springer fork was swapped for a RockShox Recon 351 air spring with lockout. Pedals are now Crank Bros Acid. Cockpit is now EA70 flat bar and stem, with a reasonably lightweight WTB seat. And tomorrow I'm swapping the Deore 8 speed rear end for SRAM X-9 mech, hub, chain, and shifter.
As it sits right now, with toolbag, pump, and lights, the bike is on the order of 31 lbs. The SRAM 9-speed upgrade will drop some weight, and I can strip the toolbag and pump for the race I guess, but I expect the "race weight" for this bike will be 28lbs or so at best.
OK, so I'm not racing the World Cup and I don't need a sub-20lb bike. Granted. But how far off the mark am I for a reasonable race bike? What's the realistic upper bound on weight?