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 Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".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 hands sit than your saddle. On a riser bar I count the bar's rise, so the drop is that much less than it is to the clamp.
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
Trifox X12
Road · 4 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
- Trifox X12 · Road · 4 sizes
- Geometry
- trifoxbike.com, fetched 20 Oct 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
- 22 October 2026 · 686 bikes, 74 makes, 3,984 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.The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The M-558 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. A dashed tube is a number the maker left out (est.).
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.
Frame facts
read from the maker's words, not a table: trifoxbike.com- Tyre clearance
- not recorded yet
- Bottom bracket
- BSA 68
- Axles and brakes
- QR
- UDH
- not recorded yet
- Seatpost
- proprietary
- Frame weight
- not recorded yet
In the maker's words
Kept whole, as I read it off trifoxbike.com.The page's specification table, verbatim: Frame: 3K Weave, T800 carbon fiber, V brake braking system, 43mm fork rake/offset.
Cockpit and seatpost, in the maker's words · 163 words
The page's specification table, verbatim: Frame: 3K Weave, T800 carbon fiber, V brake braking system, 43mm fork rake/offset. Fit for DI2 & Mechanical, BSA - BB68 (φ 34mm, L 68mm), φ10x130mm Quick Release; Type: Road Bike Frame; Fork: 43mm fork rake/offset; φ9x100mm Quick Release; Max Wheels & Tire Size: 700 * 25C, Compatible with TRIFOX Ultra-lightweight Carbon Fiber WT17 Wheelset; Seatpost insertion length: 7-12cm; Finish: Matte black with glossy color painting; Headset: 1-1/8" To 1-1/2" Tapered Integrated design; Saddle installation method: Lock up and down; Warranty: 2 years; Weight: XS - 510mm--1077g ± 20g S - 534mm--1125g ± 20g M - 558mm--1192g ± 20g L - 582mm--1199g ± 20g AERO Fork--368g ± 2g AERO Seatpost--243g ± 2g AERO Stem - 90mm--195g ± 2g AERO Stem - 100mm--196g ± 2g AERO Stem - 110mm--197g ± 2; Package Content: 1 x AERO Carbon Road Bike Frame X12 1 x AERO Fork 1 x AERO SeatPost 1 x Headset 1 x Aerostem 1 x Seatpost Clamp.
SOURCE: www.trifoxbike.com is Trifox's own store (Xiamen). Source: html table (maker's own store page, "Product Geometry" HTML table keyed by letter to a geometry drawing, each row also named; parsed from the raw HTML)
How I read the maker's table
The geometry table names every row beside its drawing letter (A (°) = Head Tube Angle, B (°) = Seat Tube Angle, C (mm) = Chainstay Length, D (mm) = BB Drop, F (mm) = Seat Tube Length, G (mm) = Stack, H (mm) = Top Tube Length Horizontal, I (mm) = Reach, J (mm) = Head Tube Length, K (mm) = Fork Length Full); "Top Tube Length Horizontal" is top_tube_effective. fork_offset 43 mm comes from the page's own specification table ("43 mm fork rake/offset"), not from the geometry table. Rows not in the schema: K (mm) Fork Length Full 368 / 368 / 368 / 368. STACK DATUM: not stated; recorded as the usual head tube top. NOT PUBLISHED: front centre, standover, trail (null), and the wheelbase. FLAGGED: the Stack row prints 510 / 534 / 558 / 582, the same numbers as the size names XS-510 / S-534 / M-558 / L-582, and on M and L reach + stack / tan(seat angle) comes out 5.1 and 11.0 mm shorter than the printed top tube (XS and S close within 2 mm); the stack row may be the size names copied in, kept as printed for Carl to judge. Size labels exactly as the table heads its columns. MODEL YEAR: not printed; model_year null. No Panda Podium, Geometry Geeks or 99 Spokes request was made.