Road endurance

Mason Definition 3

2025 · 700c wheels · 8 sizes

Third generation of Mason's Dedacciai aluminium all-road frame, a sporty, all-season road bike with full mudguard clearance and room for 35 mm tyres (32 mm with mudguards). Mason publishes one geometry table covering both the Definition and its steel sibling, the Resolution. Trail figures are Mason's own; Mason does not say which tyre size they assume. Mason's table prints the 48 cm centre-to-centre seat tube as 43.29; it should read 432.9. Stem, bar and crank sizes are from the Definition 3 Shimano build; where Mason lists two options for a size, that size is left blank.

Source: masoncycles.cc/products/definition-frameset-definition-frameset

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Size run

Published geometry by size. How each size rides and fits for your rider profile loads with the page.

Size4850525456586062
Stack (mm)532543553566580591599620
Reach (mm)370381383383388395397406
Head angle (°)71.071.571.571.571.572.072.072.5
Seat angle (°)74.574.574.573.573.572.572.572.5