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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L | 565 mm published | 428 mm published | 73.5 ° derived | 74.5 ° derived | 585 mm derived | 407 mm derived | 1023 mm published | 626 mm derived | 70 mm derived | 53.6 mm derived | 46 mm derived | green |
| All 3 consistency checks passed | ||||||||||||
| M | 541 mm published | 420 mm published | 73.5 ° derived | 75.0 ° derived | 565 mm derived | 407 mm derived | 1007 mm published | 611 mm derived | 70 mm derived | 53.6 mm derived | 46 mm derived | green |
| All 3 consistency checks passed | ||||||||||||
| S | 521 mm published | 410 mm published | 73.0 ° derived | 75.5 ° derived | 545 mm derived | 407 mm derived | 996 mm published | 600 mm derived | 70 mm derived | 56.7 mm derived | 46 mm derived | green |
| All 3 consistency checks passed | ||||||||||||
| XS | 504 mm published | 399 mm published | 72.0 ° derived | 76.0 ° derived | 525 mm derived | 407 mm derived | 993 mm published | 592 mm derived | 72 mm derived | 63.0 mm derived | 46 mm derived | yellow |
| 1 of 3 checks flagged — Wheelbase Reconciliation shows 4.8mm discrepancy | ||||||||||||
| XXS | 497 mm published | 386 mm published | 71.5 ° derived | 76.5 ° derived | 505 mm derived | 407 mm derived | 981 mm published | 581 mm derived | 72 mm derived | 66.1 mm derived | 46 mm derived | yellow |
| 1 of 3 checks flagged — Wheelbase Reconciliation shows 4.4mm discrepancy | ||||||||||||
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 Ridley Noah Fast geometry specification shows strong internal consistency across the size run, with stack and reach reconciling within ±1mm engineering tolerance on all five sizes. Wheelbase shows 4.4–4.8mm data inaccuracies on sizes XXS and XS, while sizes S–L reconcile within tolerance. The manufacturer has not published trail values; the engine forward-computes trail using the manufacturer's stated 700 x 30c reference tire.