Front-end position
Stack and reach show how the head-tube reference point moves. A larger label does not imply that both values increase by the same amount.
Boardman SLR 8.6 geometry and sizing
Source-linked frame measurements for the 2021 SLR 8.6, shown size by size without filling gaps or estimating values.
Road · 2021
4 measured sizes
Use these figures to compare frames, then confirm the current product table and test the complete bicycle. Component position and rider mobility are not captured by frame geometry alone.
| Measurement | SM | MD | LG | XL |
|---|---|---|---|---|
| Recommended rider height | 170–179 cm | 177–183 cm | 181–189 cm | 187–195 cm |
| Recommended inside leg | 74–82 cm | 78–85 cm | 82–89 cm | 86–94 cm |
| Wheel size | 700c | 700c | 700c | 700c |
| Stack | 547 | 568 | 589 | 604 |
| Reach | 378 | 384 | 390 | 400 |
| Effective top tube | 540 | 552 | 570 | 585 |
| Seat tube | 515 | 530 | 555 | 575 |
| Head tube | 140 | 160 | 180 | 195 |
| Head angle | 72° | 72.5° | 73° | 73° |
| Seat angle | 73.5° | 73.5° | 73° | 73° |
| Chainstay | 415 | 415 | 415 | 415 |
| Fork offset | 48 | 48 | 45 | 45 |
| Bottom-bracket drop | 68 | 68 | 68 | 68 |
| Crank length | 170 | 170 | 172.5 | 175 |
| Stem length | 90 | 100 | 110 | 120 |
| Handlebar width | 400 | 400 | 420 | 440 |
Using this entry
What changes through the size range
Seated cockpit
Effective top tube, seat angle, stem length and saddle position affect how stretched the complete bike feels while seated.
Steering dimensions
Head angle and fork offset may stay fixed or change by size. Wheel and tyre radius are also needed before calculating trail.
Size recommendations
Height and inside-leg bands overlap deliberately. Riders near a boundary should compare both frames and assess control access, posture and intended riding.
