Stack and reach
How high and how far forward the top of the head tube is, from the bottom bracket. They are the two numbers that decide whether a frame can be set up like yours.
BB, or bottom bracket
The axle your cranks turn on, in the middle of the frame. Every number on this site is measured from it, because it is the one point that sits in the same place on every bike.
Headset cover
The little cap on top of the head tube, under your spacers. Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".
Stem clamp, and its centre
The collar on the steerer that your stem bolts to. I need the middle of it. Where a maker gives only the height, I assume halfway up and say so on the answer.
Steerer
The tube coming up out of the fork. The cover, the spacers and the stem all sit on it, and it is the thing a mechanic cuts to length.
Bar reach
How far forward the hoods sit from the middle of the bar. Two bars on the same stem can put your hands 20 mm apart, which is why I ask.
Setback
How far your saddle sits behind the bottom bracket.
Drop
How much lower your bar is than your saddle.
Rails, and the rail centre
The two rods under your saddle, and the middle of the straight part of them. That midpoint is the point I use, because it is the one you can find with a tape.
The band
How far out I could be, in millimetres, and why. It is a straight sum of everything I had to assume rather than a clever average, so it errs wide on purpose.
wb, stand, trail
Wheelbase, standover and trail: how long the bike is, how high the top tube is where you straddle it, and how steady the steering feels. I show them against your bike, and I leave them out when the maker does not publish them.
est.
Estimated: a number I worked out rather than read off the maker's table. Anything marked this way can move if the maker publishes the real one.
Close Escape closes it. The measuring guide has the pictures. Open the measuring guide
Hongfu FM279
Gravel · 6 sizes
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This is the bike I ride
No account is needed to read the table. Report a wrong number · Correct this bike
- Bike
- Hongfu FM279 · Gravel · 6 sizes
- Geometry
- hongfu-bikes.com, fetched 29 Aug 2026, re-checked, no differences
- Cockpit
- Generic stem and bar, assumed
- Solved with
- cover 15 mm (assumed), max spacers 40 mm (assumed), stem clamp centre 20 mm (assumed), so every verdict carries ±10 mm at the bar
- Sheet
- 6 September 2026 · 210 bikes, 43 makes, 1,262 sizes in the catalogue
Geometry, every size, from the maker's table
The tinted row is the size drawn beside it. Press a size to draw it.| Size | Stack (mm) | Reach (mm) | Head angle (deg) | Seat angle (deg) | Head tube (mm) | Chainstay (mm) | Wheelbase (mm) | Standover (mm)not published |
|---|---|---|---|---|---|---|---|---|
| 500 (50 cm) | 518.2 | 375 | 70.5 | 75.5 | 100 | 425 | 1005.2 | |
| 520 (52 cm) | 529.5 | 380 | 71 | 74.5 | 110 | 425 | 1009.5 | |
| 540 (54 cm) | 554 | 382 | 71.5 | 74 | 135 | 425 | 1020 | |
| 560 (56 cm) | 566.4 | 386 | 72 | 73 | 145 | 425 | 1018.1 | |
| 580 (58 cm) | 580.6 | 391 | 72 | 73 | 160 | 425 | 1027.6 | |
| 600 (60 cm) | 604.4 | 398 | 72 | 73 | 185 | 425 | 1042.5 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The 560 (56 cm) drawn to scale from the table, with no build on it. Stack and reach run from the bottom bracket to the top of the head tube; every size is solved from those two. One square is 100 mm.
The maker's cockpit
No stock cockpit I can name, so every size is solved on a generic stem and bar unless you choose one on the sheet.Generic stem and barAssumedNo bar is listed for this frame.
In the maker's words
Kept whole, as I read it off hongfu-bikes.com.NOT published.
Cockpit and seatpost, in the maker's words · 167 words
NOT published. The maker's page (HongFu Sports Equipment / Shenzhen Hongfu Sports Goods Co., Ltd) lists the frame only: 'Full carbon Gravel Disc Frame FM279', '2018 Gravel Disc Frame HF-FM279, Model(Frame): HF-FM279, Material: Toray T800, Weave: UD, Fork: Axle M15*p1.5/M12-p1.5, Frame: Axle M12, Disc brake: Shimano Flat Mount, Size: 50/52/54/56/58cm, Suitable Tire: disc brake 700C*42mm, BB: BB86/BSA'. No handlebar, stem, spacer, top-cap or seatpost details are given and whether a bar/stem is included is not stated (integrated_cockpit left null; the frame photo shows a conventional round steerer with external cable ports, so a normal stem and bar would be expected). Headset, from the geometry drawing only: 'head set: FSA-NO.42ACB, UP 1-1/8", bottom 1.5"' (tapered steerer, 1-1/8 in upper, 1.5 in lower). Fork: full-carbon disc fork, length (F in the drawing) 400 mm axle-to-crown, offset (OT) 45 mm, all sizes; the fork axle spec 'M15*p1.5/M12-p1.5' reads as a 15 mm or 12 mm thru-axle thread option, axle widths not stated. Seatpost diameter, length and offset are NOT published.
Geometry read by eye from the maker's own drawing image http://www.hongfu-bikes.com/upload/image/20220413/1649821213931850.jpg (650x556 JPEG embedded in the product overview. Source: image_table
How I read the maker's table
table captioned 'FM279-Cycle cross' frame data table, units mm and degrees; upscaled 3x to read). The maker files the bike under Gravel bike and titles it 'Gravel Disc Frame', while the drawing calls it 'Cycle cross' - category recorded as gravel per the maker's listing. STACK DATUM: Stack is drawn from the BB centre vertically to the horizontal through the top of the head tube and Reach horizontally from the BB vertical to the head tube top centre - the usual convention. INTERNAL CONSISTENCY: sqrt(FC^2 - drop^2) + sqrt(RC^2 - drop^2) reproduces the published wheelbase to within 0.1 mm on sizes 500, 520, 560 and 580, but NOT on 540 (published 1020, computed 1015.2) or 600 (published 1042.5, computed 1047.0); the cells were re-read at 3x and are as printed (540: FC 597.7, WB 1020; 600: FC 629.4, WB 1042.5), so this is a maker inconsistency of about 5 mm on those two rows, recorded as published and not smoothed. Note also that the 560 wheelbase (1018.1) is shorter than the 540 (1020) as printed. Size names: the table has six sizes 500-600; the text says 'Size: 50/52/54/56/58cm' but the weight list also includes 60cm, so six sizes are recorded with size_label carrying both forms. Standover and trail are NOT published (left null; do not import derived values). Weight per size (frame, published): 50cm 1070+-40 g, 52cm 1090+-40 g, 54cm 1110+-40 g, 56cm 1155+-40 g, 58cm 1165+-40 g, 60cm 1190+-40 g. Model year: the description opens '2018 Gravel Disc Frame HF-FM279'; the page record was published 2022-04-13 and the og:url points at /products/gravelbike/17.html, the article link at /case/17.html, all the same record. The gravel category listing on the maker's site (http://www.hongfu-bikes.com/products/gravelbike/) has three entries: this FM279 and two FM188 pages; the maker's Download section holds only two 2016 catalogue PDFs (hf2016_a.pdf, hf2016_b.pdf), not fetched. No aggregator was consulted.