Good to know: Saddle tilt in steps only
Saddle tilt in steps only. The seatpost has a serrated clamp, so saddle tilt only adjusts in steps of about 3°. If you need something in between, an inexpensive aftermarket seatpost fixes it.
Geometry ?
Triban RC120 Disc 2026 geometry in sizes XS–XL: stack 539–640 mm, reach 376–385 mm, head angle 71.5–73°.
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| Stack | 539 mm | 555 mm | 580 mm | 611 mm | 640 mm |
| Reach | 376 mm | 376 mm | 376 mm | 383 mm | 385 mm |
| Head angle | 71.5° | 72° | 72.5° | 73° | 73° |
| Seat angle | 74.5° | 74° | 73.5° | 73.5° | 73° |
| Seat tube (?) | 450 mm | 480 mm | 500 mm | 520 mm | 530 mm |
| Head tube | 125 mm | 140 mm | 165 mm | 195 mm | 225 mm |
| Top tube (effective) | 525 mm | 535 mm | 548 mm | 564 mm | 580 mm |
| Chainstay | 425 mm | 425 mm | 425 mm | 425 mm | 425 mm |
| Wheelbase | 1001 mm | 1001 mm | 1005 mm | 1016 mm | 1026 mm |
| Stock build by size | |||||
| Cranks | 170 mm | 170 mm | 170 mm | 170 mm | 170 mm |
| Stem | 80 mm | 80 mm | 100 mm | 110 mm | 110 mm |
| Stem angle | −6°✓ | −6°✓ | −6°✓ | −6°✓ | −6°✓ |
| Bar width | 400 mm | 400 mm | 420 mm | 420 mm | 440 mm |
| Spacers | 25 mm✓ | 25 mm✓ | 25 mm✓ | 25 mm✓ | 25 mm✓ |
| Seatpost setback | 15 mm✓ | 15 mm✓ | 15 mm✓ | 15 mm✓ | 15 mm✓ |
✓ measured on a bike during a fit (4 Nov 2026)
(?) by the seat tube length: the manufacturer doesn’t say whether it’s measured centre to centre (c-c) or centre to top (c-t).
Source: decathlon.sk, checked 1 Nov 2026 · bar position: worked out from published data
Stock build
RC120 Disc microSHIFT 8s
- Groupset
- microSHIFT 2×8, Promax DSK-300R mech. disc
- Shifters
- microSHIFT 8-speed lever
- Cranks
- Wheeltop 48×34
- Stem
- B'Twin/Triban alloy stem 31.8 / 1-1/8"
- Handlebar
- Triban ergonomic alloy bar
- Seatpost
- Triban aluminium 27.2
- Saddle
- Triban ErgoFit
Source: decathlon.sk, checked 1 Nov 2026
Frames with similar geometry
Stack and reach within 12 mm of size XS (stack 539 / reach 376 mm).
Stack and reach within 12 mm of size S (stack 555 / reach 376 mm).
Stack and reach within 12 mm of size M (stack 580 / reach 376 mm).
Stack and reach within 12 mm of size L (stack 611 / reach 383 mm).
Stack and reach within 12 mm of size XL (stack 640 / reach 385 mm).
Spotted a mistake or a missing build? Let me know.