Genesis Croix de Fer 30 Rotor Fit: Diameter, Bolts and Mounts

2026-10-27

Genesis Croix de Fer 30 rotor fit involves more than a disc's diameter. For GN21050, the manufacturer's sheet lists TRP TR160 rotors, 160mm diameter and a six-bolt connection. It separately records Flat Mount 140 as the brake-mount type. These entries describe different interfaces and should not be read as competing rotor-size recommendations.

Historical black Genesis Croix de Fer with racks and mudguards beside a river, photographed in 2018 — Historical Genesis Croix de Fer identified by its photographer as a 2014 model, photographed in 2018. It illustrates the family, not the GN21050 build or its component compatibility. No endorsement implied. Original photograph source (https://commons.wikimedia.org/wiki/File:02f-Genesis_Croix_De_Fer2014_(NgnL)--2.jpg)

Genesis Croix de Fer 30 rotor fit: Separate rotor, hub and frame information

The specified rotors attach at the wheel. The same equipment table identifies Formula front RX-812 and rear RX-300 hubs with six-bolt fittings. A rotor's attachment needs to match the actual hub; a familiar bicycle model name does not convert one attachment standard into another.

The frame or fork brake-mount entry concerns where the braking assembly is supported. Keep it separate from the listed rotor and wheel-hub connection. Copying only the words flat mount into a rotor purchase request leaves important wheel-side information unstated.

Explain the apparent 140 and 160 difference

The GN21050 table contains both the Flat Mount 140 field and the fitted 160mm rotor specification. It does not identify every adapter or replacement arrangement needed to reproduce that setup. Those two numbers are therefore a reason to identify the whole assembly, not an instruction to replace the fitted rotor with a 140mm disc.

A replacement request should include the actual caliper, front or rear position, rotor marking and hub attachment. Preserve photographs of the installed parts if a workshop needs them. An original specification alone cannot certify that a previously modified bicycle remains in its original configuration.

Avoid inventing an upgrade limit

The sheet's fitted rotor size is not a statement of the largest permissible rotor. Do not infer that a larger disc is allowed because it shares six bolt holes or because an adapter is sold separately. The relevant frame, fork and brake instructions must support the proposed arrangement.

This guide gives no torque settings, adapter part number or fitting procedure. The historical Croix de Fer photograph is family context and does not reveal every interface in the GN21050 specification.

Take the right identifiers to the shop

Use the Genesis topic alongside the brand introduction for the wider range, but keep this component request specific. Recording rotor diameter, attachment, installed caliper and position helps prevent one correct number from being used to order an otherwise unsuitable part.

FAQ

What rotor size and attachment does GN21050 list?

It lists TRP TR160 rotors at 160mm with a six-bolt attachment.

Does the Flat Mount 140 entry instruct me to fit a 140mm rotor?

No. The same sheet specifies a fitted 160mm rotor, so the full assembly must be identified.

Does matching six-bolt attachment approve a larger rotor?

No. A larger rotor also needs approval for the actual frame, fork and brake arrangement.

Sources

Rotor diameter and six-bolt attachment are listed beside hub details; the frame brake-mount field is separate. An adapter model and maximum permissible rotor are not supplied. Genesis Croix de Fer 30 manufacturer specification, GN21050, pages 1–2 (https://www.freewheel.co.uk/media/madison/product-files/525553/Genesis_Croix_De_Fer_30_VARGN21050.pdf). Original evidence retrieved 26 October 2026; saved document rechecked 27 October 2026; the code identifies the document, without inferring its model year.

Photograph credits and permissions

Photograph 1

Original title: Bike Resting at Ruillé-sur-le-Loir Campsite, France

Creator: nogoodnamesleft.net (Commons contributor No(0)GoodNamesLeft)

Original source URI: https://commons.wikimedia.org/wiki/File:02f-Genesis_Croix_De_Fer2014_(NgnL)--2.jpg

License / permission: CC BY-SA 4.0 International

License / permission URI: https://creativecommons.org/licenses/by-sa/4.0/

Modification notice: Wikimedia-provided 1280 × 611 downscaled JPEG delivery of the original photograph. No crop or further image edits by this publisher.

Source disclaimer: The creator says notification of use outside Wikimedia projects would be appreciated but is not a condition of use.