dsc1254j dsc1265v
dsc1256o dsc1255q 
I’ve been following this guy’s build for awhile on Weight Weenies and it’s amazing to see the time and resources he’s put into the whole thing.  The frame is a Crumton UL custom build that comes out to 680 grams!  The end product is nothing short of impressive.

So here's the final build. I've actually added about 120g by switching from the aerolites to the Keo blades. I may switch back to the Aerolites at some point but I need to get another pair of shoes, since I'm also using the Keo Blades on my Ruegamer. It's too much time to switch out cleats. The final weight is 4.51kg with the Enve 1.25 wheels and 4.71kg with the Enve 1.45 wheels. Currently I'm using the Veloflex Extreme Tires (500g), which are pretty heavy...but nice. I could get the bike into the 8lb range with a set of Tufo tires (-250g) and the aerolites (-120g). I also need to cut the fork, get rid of the spacers and file down the lawyer tabs. :wink:

Crumpton UL 666g (680g with matte finish)
THM Scapula SP fork 279g (uncut) (sanded with 6g of matte finish. Not sure of the final weight but it's lighter than the original 279g)
AX lightness AX4000 42cm Handlebars 144g (shortened...not sure of their final weight)
Lizard skin 1.8 Bar tape (50g?)
AX lightness Zeus Stem 110mm 65.5g
Berk Saddle Seatpost combo 120g (Test combo)
Thm Clavicula Crank "Tuned" 318g (324g original weight)
HSC PF30 ceramic bb 74g
FIbrelyte50t = 53g
FIbrelyte 36t = 25g
Red RDer = "Tuned" 112g (145g original weight)
Red FDer = "Tuned" 63g (69g original weight)
Red shifters = "Tuned" 254g (323g original weight)
BTP cage = 13g
Far and near chainring bolts 8g
AX lightness Orion brakes w/ carbon spring 118g (123g original weight)
BBB roadstop brake pads 19g
Look Keo Blade 185g
Mcfk seat collar 8g
Mcfk derailleur clamp 7g
KCNC Morion M1 33g
Tune Top cap 5g
•ENVE 1.25 931g + Recon (11-23) 88g + Veloflex Extremes 500g
(w/ 6g of stickers removed)
•ENVE 1.45 1023g + Kcnc cassette (11-23) 117g + Veloflex 525g
(w/ 11g of stickers removed)

Source:  Gum’s Crumpton