Mason Definition
Endurance road · 8 sizes
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- Bike
- Mason Definition · Endurance road · 8 sizes
- Geometry
- masoncycles.cc, 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.| Size | Stack (mm) | Reach (mm) | Head angle (deg) | Seat angle (deg) | Head tube (mm) | Chainstay (mm) | Wheelbase (mm) | Standover (mm) |
|---|---|---|---|---|---|---|---|---|
| 48CM | 532.1 | 369.7 | 71 | 74.5 | 120 | 420 | 989 | 741.4 |
| 50CM | 543.3 | 380.6 | 71.5 | 74.5 | 130 | 420 | 999.1 | 756.5 |
| 52CM | 552.8 | 382.5 | 71.5 | 74.5 | 140 | 420 | 1004.1 | 770.8 |
| 54CM | 565.5 | 383 | 71.5 | 73.5 | 155 | 420 | 1009.6 | 787.3 |
| 56CM | 579.7 | 388.3 | 71.5 | 73.5 | 170 | 420 | 1019.7 | 804 |
| 58CM | 591.1 | 394.7 | 72 | 72.5 | 180 | 420 | 1024.7 | 818.1 |
| 60CM | 599.1 | 396.8 | 72 | 72.5 | 190 | 420 | 1030.2 | 833.1 |
| 62CM | 620.1 | 405.5 | 72.5 | 72.5 | 210 | 420 | 1040.2 | 853.2 |
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 size48CM 70, 52CM 90 x 420, 54CM 100 x 440, 56CM 110 x 440, 58CM 110 x 460, 60CM 120 x 460, 62CM 120 x 460 (stem length x bar width, mm)
Frame facts
not read off the maker's page yet: masoncycles.cc- Tyre clearance
- not recorded yet
- Bottom bracket
- not recorded yet
- Axles and brakes
- not recorded yet
- UDH
- not recorded yet
- Seatpost
- not recorded yet
- Frame weight
- not recorded yet
In the maker's words
Kept whole, as I read it off masoncycles.cc.No cockpit with the frameset.
Cockpit and seatpost, in the maker's words · 95 words
No cockpit with the frameset. Complete builds (Definition Shimano / SRAM / Campagnolo builds) come with bars, stem and cranks "pre-set to match frame size": the chart's STEM row prints stem lengths 70 (48cm), 80/90 (50cm), 90 (52cm), 100 (54cm), 110 (56cm and 58cm), 120 (60cm and 62cm) mm and its HANDLEBAR (OUTSIDE DIMENSION) row prints 40/42, 40/42, 42, 44, 44, 46, 46, 46 (cm, outside dimension) for 48cm to 62cm. Two-piece bar and stem (the frameset comes with a Deda headset, expander bung and top cap); no bar is named on the frameset page.
OFFICIAL SOURCE: Mason Cycles (masoncycles.cc, Brighton UK) product page for the Definition 3 Frameset, eight sizes 48CM to 62CM, labels as printed in the chart header. Source: html table (official Mason Cycles product page "Definition 3 Frameset", the "Full geometry chart" table in the page markup; fetched 2026-10-20
How I read the maker's table
The page says the Definition shares "the overall geometry of our Columbus steel Resolution" and is the third version ("Key changes in Definition 3.0"). stock_bar_width is the HANDLEBAR row converted from cm to mm (42 -> 420) where a single width is printed, and is the bar's OUTSIDE dimension as the maker labels it, not centre to centre; null on 48CM and 50CM where two widths are printed (40/42). stock_stem_length null on 50CM where "80/90" is printed. Some angle cells carry a degree sign in the markup (71.5º), stripped by the parser. Stack datum: Mason's diagram draws stack to the head tube top; no headset cover height is given. Max tyre clearance "700C x 35mm [approx. 700C x 32mm with mudguards]". Seat tube: 48-58cm take a 27.2 mm post, 60 and 62cm a 31.6 mm post. Model year: not printed; Bike Insights files this table as its "2023" Definition version (its source link https://masoncycles.cc/products/definition-frameset).
Source: html table (official Mason Cycles product page "Definition 3 Frameset", the "Full geometry chart" table in the page markup; fetched 2026-10-20, HTTP 200)