Ridley Noah Fast Sizing: Why Top-Tube Length Matters in the 3.0 Comparison
Ridley Noah Fast sizing can be confusing when the newer frame shows more reach than an earlier Noah Fast. Ridley’s Noah Fast 3.0 support guidance explains that its steeper seat tube angle changes the reach number while the actual top-tube length remains the same in the comparison described. The manufacturer recommends comparing actual top-tube length, rather than choosing by reach alone.
Ridley Noah Fast sizing and the seat-angle explanation
Ridley gives a medium-size example: a 75-degree seat tube angle compared with 73 degrees on the previous Noah or Noah Fast. It explains that a larger portion of the actual top tube then sits in front of the bottom bracket, increasing the reach number without increasing that top-tube length.
That is a specific comparison between the generations in the support entry. It should not become a claim that every newer frame has the same fit as an older bike, or that reach is meaningless. It explains why a single figure can be misleading when the rest of the geometry changes.
Compare the existing position before choosing a label
The corresponding size FAQ advises comparing the actual top-tube length of the rider’s current bike with the Noah or Noah Fast. It also recommends a local dealer for a detailed bike fit. It does not supply a height-to-size answer for every rider in that short entry.
Bring the identity and dimensions of the current bicycle to the comparison, together with its cockpit arrangement. Matching a frame label alone leaves the contact-point setup unresolved. Treat the top-tube comparison as Ridley’s starting point, not a complete assessment of the rider’s posture or adjustment range.
The cockpit remains a separate part of the position
The Nimbus Aero support page defines stem reach as the horizontal contribution from steerer center to handlebar center, and stem stack as the contribution above frame stack. It lists 55, 75 and 100 mm stem-stack choices. Those component dimensions belong beside the frame comparison.
Two frames can therefore require different cockpit choices to address a rider’s intended position. The cited guidance does not establish which choice is correct for an individual. Nor can the historical X-Bow photograph settle a Noah Fast size: it is a different bicycle, shown only as historical Ridley context. The Ridley introduction gives broader model context for the frames in the brand range.
FAQ
Does the cited reach increase mean the top tube became longer?
No. Ridley says the compared geometry retains the same actual top-tube length.
What seat-angle example does Ridley give for medium?
It gives 75 degrees compared with 73 degrees on the previous model.
Does this article assign a frame size from rider height?
No. The cited FAQ recommends comparison and a dealer’s detailed bike fit.
Sources
Manufacturer records for Ridley Noah Fast sizing: Manufacturer support directory and model grouping (https://www.ridley-bikes.com/en_US/support/folders/63000157885). Noah Fast 3.0 sizing FAQ (https://www.ridley-bikes.com/en_US/support/folders/63000157885/article/63000285398). Noah generation reach explanation (https://www.ridley-bikes.com/en_US/support/folders/63000157885/article/63000286138). Nimbus Aero dimension definitions (https://www.ridley-bikes.com/en_US/support/folders/63000157885/article/63000286139). Retrieved 28 October 2026. The historical photograph is credited separately above and below.
Photograph credits and permissions
Photograph 1
Original title: Ridley.jpg
Creator: Pinguinsen
Original source URI: https://commons.wikimedia.org/wiki/File:Ridley.jpg
License / permission: CC BY-SA 4.0
License / permission URI: https://creativecommons.org/licenses/by-sa/4.0/
Modification notice: Original 800×600 JPEG used without cropping, retouching or re-encoding by this publisher. Photograph remains under CC BY-SA 4.0.