Wanted a fast, lightweight daily driver with flat bar ergonomics and MTB shifting. Nothing like that exists off the shelf at a sane price, so I built it.
Why Flatbar on an XL frame?
Swap a drop bar for a flat bar and you lose ~80mm of effective reach — the hoods just aren't there anymore. To compensate, I went one (massive) size up to XL and paired it with a 130mm stem. The result matches my drop bar bike's reach almost exactly: same aggressive, stretched position, but with upright sightlines and the ability to run a full Shimano XT groupset off the MTB shelf for a fraction of GRX pricing.

The build:
Frame & Cockpit
Mondince FM316 XL (wanted purple, but got midnight-blue - ok, i´m fine with it haha)
Carbon rigid fork (just clearcoat)
Toseek Carbon Flatbar — 660mm
Kalloy Uno stem 130mm
Kactus Tech Ceramic T47 BB

Wheels & Tyres:
Elite Wheels Gravel Pro Carbon — 24mm inner width, swap to MicroSpline freehub
Tufo Thundero HD 44mm Tyres - love them!

Drivetrain:
SRAM Rival E1 Wide crankset — 165mm (cheaper than GRX)
Alugear Oval 42T chainring — 2mm offset (chains the chainline to 49.5mm for the 142mm rear axle)
Shimano Deore XT 12-speed — shifter, derailleur, 10-51T cassette (crazy cheap! 180€ total + 3 XT chains waxed)

Brakes:
Shimano XT M8100 levers + Flatmount calipers (for 120€ total)
180mm front / 160mm rear

Total weight: ~9.1kg with pedals, mounts, everything / Price: ~1800€ in germany
Happy to go deep on the chainline math or the geometry sizing logic if anyone's interested. Attatched a pic in comparsion with Tideace GV201 size 54.

Please help me out with the sizing of this frame, it's difficult for me to decide which size would be right for me.

If I choose the size 54, then all the sizes are perfect, but the reach is too long. To compensate this, I would need an 80 mm stem which is very short.

If I choose the size 52, the reach is fine with my originally used 100 mm stem, but the stack would be very low and I would need at least 30–40 mm of spacers, which I think wouldn’t look good.

For reference, I'm 178 cm tall and my inseam is 82 cm.

Which one do you think would be more ideal?

Hi there, I'm 180cm, same inseam. Got a size 54 with a Lexon 420/80 mm handlebar. All spacers installed. Works good for me, handling is stable on fast descents.

Hi there, i also considered buying the frame. I asked Jim about pricing:

The max tire is 700*50C or 650B*2.1'' or 29er*1.95'', so 29er*2.1" can not fit for it, the edge of the tire touches the frame.
Frame LCG074-D, including frame+ seat post + fork + handlebar + seat clamp+ head set+ front & rear thru-axle, and two hangers for rear derailleur.
Color: UD matt, (painting customized is acceptable with extra cost.)
frame set included one storage bag as gift.
price is USD$823/set including shipping cost and all duties to Germany, we need confirm your address first.
If pack two frames in one carton, price can be cheaper.
size 49/52/55/58cm,
flared handlebar size 400/420/440*90/100/110/120mm,
fork with or without holes on legs,
bottom bracket T47 cost USD$15/pc if you want, have three oprions: 85.5-24 for shimano, 85.5-30 for sram. 85.5-29 for DUB,
seat post SP01 non-offset, or SP02 25mm offset, if SP03 15mm offset, cost is higher USD$10，
bottle cage BC205, cost USD$12/pc,
carbon saddle SD01 cost USD$79/pc including shipping cost raised