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 Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".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
Dengfu R12 Disc
Aero road · 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
- Dengfu R12 Disc · Aero road · 6 sizes · integrated cockpit
- Geometry
- dengfubike.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 |
|---|---|---|---|---|---|---|---|---|
| 49cm | 508 | 374 | 71 | 75 | 105 | 408 | 971.6 | |
| 52cm | 525.6 | 384 | 72 | 74.5 | 120 | 408 | 978.9 | |
| 54cm | 546.4 | 393 | 72.5 | 74 | 140 | 408 | 990.1 | |
| 56cm | 567.2 | 397 | 73 | 73.5 | 160 | 408 | 995.4 | |
| 58cm | 596 | 403 | 73 | 73 | 190 | 408 | 1010 | |
| 61cm | 612 | 413 | 73.5 | 73 | 205 | 408 | 1019.8 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The 56cm 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.
Stock stem and bar per size49cm 90 x 400, 52cm 100 x 400, 54cm 100 x 420, 56cm 110 x 420, 58cm 110 x 440, 61cm 120 x 440 (stem length x bar width, mm)
In the maker's words
Kept whole, as I read it off dengfubike.com.INTEGRATED one-piece bar/stem: Dengfu HB015 INTEGRATED HANDLEBAR (https://www.dengfubike.com/products/hb015): Toray T700 carbon, stem lengths 90 / 100 / 110 / 120 mm, widths 380 / 400 / 420 / 440 mm, reach 84.5 mm, drop 128 mm, internal cable routing, 350 g, UD matt or glossy.
Cockpit and seatpost, in the maker's words · 219 words
INTEGRATED one-piece bar/stem: Dengfu HB015 INTEGRATED HANDLEBAR (https://www.dengfubike.com/products/hb015): Toray T700 carbon, stem lengths 90 / 100 / 110 / 120 mm, widths 380 / 400 / 420 / 440 mm, reach 84.5 mm, drop 128 mm, internal cable routing, 350 g, UD matt or glossy. The complete-bike page lists the bar only as "TORAY T700 carbon fiber, Reach 84.5mm, Drop 128mm, aerodynamic" (same reach/drop as HB015); the frameset page (https://www.dengfubike.com/products/r12-disc-frame) states the frameset includes "frame, fork, seatpost, seat clamp, HB015 integrated handlebar, spacers, headset, thru axles". Stock bar width and stem length per size come from the HB and STEM rows of the geometry table (HB 400/400/420/420/440/440, STEM 90/100/100/110/110/120 for 49/52/54/56/58/61) with the maker's footnote: "*The size of the HANDLEBAR (HB) and STEM is optional according to your requirement. If need, please note when placing the order." Stem angle, stem/clamp height, headset cap height, spacer heights and maximum spacer stack are NOT published. Headset: "Integrated internal routing, 1 1/8\"-1 1/2\"" (tapered). Seatpost: Toray T700 carbon aero D-shape seatpost; the complete-bike page says 350 mm, the frameset page says 400 mm; offset/setback NOT published. Cranks on the complete bikes are 172.5 mm at every level (Shimano 105 R7000 / Ultegra R8000 / Dura-Ace R9100, 50-34T, 11-28T). Three build levels (Economical / Standard / Professional), same frame and geometry for all.
SOURCE: www.dengfubike.com is Dengfu's own Shopify store (vendor "DENGFU", "Affordable carbon bikes"). Source: html_table (brand site, GEOMETRY tab is a real HTML table plus a labelled diagram image
How I read the maker's table
The GEOMETRY tab on the complete-bike page is an HTML table (rows SIZE, ST, HT, G, SA, HA, RC, WB, TT, OF, F, STACK, REACH, HB, STEM x 49/52/54/56/58/61cm); the frameset page https://www.dengfubike.com/products/r12-disc-frame carries the IDENTICAL table (same Shopify tab "r12-disc-geometry") and the same diagram image. effective top tube; OF = fork offset (rake); F = fork length axle-to-crown 370 mm all sizes (not in the schema); STACK and REACH; HB = handlebar width; STEM = stem length. STACK DATUM: the diagram draws STACK vertically from the BB centre up to a horizontal dashed line at the TOP OF THE HEAD TUBE (frame, below the headset cap and integrated bar), and REACH horizontally from the BB centre to that same point - the conventional frame stack/reach. SIZE NAMING: sizes are nominal cm labels 49/52/54/56/58/61 while the actual seat tube lengths are 470/490/510/530/550/580, so the label overstates the seat tube by 20-30 mm. NOT PUBLISHED (left null): standover, front centre, trail, rider height / size guide, seatpost offset, stem angle. Two decimals in the table are the maker's (wheelbase 971.6 / 978.9 / 990.1 / 995.4 / 1019.8; stack 525.6 / 546.4 / 567.2). CONSISTENCY CHECKS by the collector: (1) top tube: reach + stack / tan(SA) reproduces the published TT within 0.3 mm on all six sizes (510.1 / 529.8 / 549.7 / 565.0 / 585.2 / 600.1 vs 510 / 530 / 550 / 565 / 585 / 600), which confirms TT is horizontal/effective, SA is measured through the BB centre, and stack/reach share the head-tube-top datum; (2) stack recomputed from BB drop, head tube length, fork length 370, offset 43 and head angle comes out a constant 4.2-4.4 mm below the published stack on every size (the lower headset cup / crown race height, not published) - consistent; (3) wheelbase recomputed from reach, head tube, fork, offset, head angle, chainstay and drop lands 1.1-1.7 mm under the published figures on every size - consistent with the same headset allowance. FRAME FACTS: Toray T700 carbon, aerodynamic tube shapes ("AERODYNAMIC DESIGN" highlight, aero D-shape seatpost, aero bar) - hence category aero road; full internal cable routing through the head tube; flat mount disc; 142x12 rear / 100x12 front thru axles; bottom bracket BB386 on the complete bike ("ENHANCED BB386 BOTTOM BRACKET"), "BB386 or BB86" on the frameset; Di2 compatible; max tyre 700x32C; frame weight 1150 +/- 45 g (frameset page, size not stated); braze-on front derailleur mount; UD matt or glossy. Complete-bike prices on 2026-08-29: USD 1,899 Economical (105 R7000 mechanical, TRP mechanical discs, 40 mm alloy wheels), 2,899 Standard (Ultegra R8020 hydraulic, 50 mm carbon wheels), 4,699 Professional (Dura-Ace Di2 R9170, 50 mm carbon wheels on DT Swiss 350); bikes ship pre-assembled in two cartons. A separate listing "R12 DISC with SHIMANO R7020 groupset" (handle r12-disc-with-shimano-r7020-groupset, created 2023-06-13) exists in the store index and was not fetched. MODEL YEAR: undated on the site. Shopify product records: complete bike created 2019-05-09, frameset created 2019-07-29, geometry image version stamp v=1567043160 (2019-08-29); both pages last updated 2026-08-29 and in stock, so the R12 Disc is a 2019 design still sold unchanged in 2026 - model_year left null rather than guessed.
Source: html_table (brand site, GEOMETRY tab is a real HTML table plus a labelled diagram image https://cdn.shopify.com/s/files/1/0245/4929/4185/files/R12_GEOMETRY_2048x1148_2e6fbb19-c023-49d6-a7fa-5932f4adc067_2048x2048.png used only to decode the column labels; image NOT stored)
