A size-by-size geometry profile with manufacturer provenance and RideDNA consistency-audit context. Use the complete table to compare fit and handling before opening the interactive tools.
Source: Manufacturer geometry source
Provenance: published is present in the manufacturer data; derived is calculated by RideDNA; manual is a staff-entered reference rather than a manufacturer-chart value. “Not published” means the manufacturer did not provide a value for that size.
| Size | Stack | Reach | HTA | STA | ETT | Chainstay | Wheelbase | Front center | BB drop | Trail | Fork offset | Audit context |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 47 | 525 mm published | 370 mm published | 71.4 ° derived | 74.2 ° derived | 520 mm derived | 415 mm derived | 982 mm published | 579 mm published | 75 mm derived | 63.0 mm published | 50 mm published | green |
| All 5 consistency checks passed | ||||||||||||
| 51 | 550 mm published | 379 mm published | 71.4 ° derived | 74.2 ° derived | 537 mm derived | 415 mm derived | 1000 mm published | 596 mm published | 75 mm derived | 63.0 mm published | 50 mm published | yellow |
| 3 of 5 checks flagged — Reach Reconciliation shows 2.6mm discrepancy | ||||||||||||
| 54 | 570 mm published | 383 mm published | 72.2 ° derived | 74.2 ° derived | 546 mm derived | 415 mm derived | 997 mm published | 594 mm published | 75 mm derived | 63.0 mm published | 45 mm published | yellow |
| 1 of 5 checks flagged — Reach Reconciliation shows 2.1mm discrepancy | ||||||||||||
| 56 | 595 mm published | 388 mm published | 72.2 ° derived | 74.2 ° derived | 559 mm derived | 415 mm derived | 1010 mm published | 607 mm published | 75 mm derived | 63.0 mm published | 45 mm published | yellow |
| 3 of 5 checks flagged — Reach Reconciliation shows 2.8mm discrepancy | ||||||||||||
| 58 | 620 mm published | 393 mm published | 72.2 ° derived | 74.2 ° derived | 571 mm derived | 415 mm derived | 1023 mm published | 620 mm published | 75 mm derived | 63.0 mm published | 45 mm published | yellow |
| 3 of 5 checks flagged — Reach Reconciliation shows 2.8mm discrepancy | ||||||||||||
| 61 | 645 mm published | 398 mm published | 72.2 ° derived | 74.2 ° derived | 581 mm derived | 415 mm derived | 1036 mm published | 633 mm published | 75 mm derived | 63.0 mm published | 45 mm published | green |
| All 5 consistency checks passed | ||||||||||||
Overall consistency: yellow. This context is shown alongside the table so a rider can distinguish a complete published specification from a value that RideDNA had to derive or could not independently verify.
The BMC RoadMachine geometry shows systematic reach discrepancies on sizes 51, 54, 56, and 58, ranging from 2.1mm to 2.8mm — these are data inaccuracies in the published values. Wheelbase and front center show parallel discrepancies on sizes 51, 56, and 58, ranging from 2.1mm to 3.0mm, also classified as data inaccuracies. Stack and trail reconcile within ±1mm engineering tolerance across all sizes. The forward model used Effective Top Tube (ETT) as the geometry anchor — the simultaneous reach and front center discrepancies on sizes 51, 56, and 58 indicate a mutual inconsistency exists among the published ETT, reach, and front center values for those sizes, where the BB position each implies differs significantly from the others.