Genesis Croix de Fer 30 Tyre Clearance: Front and Rear Limits
Genesis Croix de Fer 30 tyre clearance is not one number shared by both wheels. The manufacturer's GN21050 specification separates front from rear and 700c from 650b. Before choosing wider rubber, identify that build and the wheel format actually fitted. These figures describe that document, rather than every bicycle carrying the Croix de Fer name.
Genesis Croix de Fer 30 tyre clearance: Read all four clearance entries
For 700c wheels, the GN21050 sheet lists 45c at the rear and 50c at the front. For 650b, it lists 44c rear and 50c front. A tyre that falls inside the front entry can therefore exceed the rear entry. Reading only the largest number would miss the part of the bicycle that sets the tighter constraint.
| Wheel format | Rear | Front |
|---|---|---|
| 700c | 45c | 50c |
| 650b | 44c | 50c |
The same sheet lists 700x40c tubeless-ready tyre options in the original equipment section. Fitted tyre size and stated maximum clearance answer different questions: one records the specified build, while the other describes the manufacturer's listed boundary. Neither establishes the exact width of an unfamiliar tyre on a changed rim.
Keep wheel format attached to the width
Write down the complete tyre marking and whether the proposed wheel is 700c or 650b. Do not transfer a rear limit from the other wheel-format row simply because both tyres have similar nominal widths. A replacement wheel also has to satisfy the bicycle's other interface requirements.
Check the bicycle around the tyre
The manufacturer's sheet does not label these numbers as guaranteed clearance with every mudguard installed. Its separate confirmation of mudguard mounting points is not a promise that any tyre and guard combination fits. Include guards and their stays when asking about a real setup.
The historical photograph shows a different, source-identified 2014 Croix de Fer with fitted accessories, captured in 2018. It illustrates why the equipment around a wheel matters. It does not measure the GN21050 frame or confirm the clearance of a modern replacement tyre.
Identify the document before buying
Keep the product code with the notes you send to a retailer. A newer specification, another frame material or a different fork can change the relevant answer. Do not average conflicting figures or select whichever allows the widest tyre.
The Genesis introduction explains the family's development; the Genesis topic collects related equipment questions. For this purchase, the useful result is a wheel-specific specification and a check of the actual installed parts, without treating a family name as a clearance measurement.
FAQ
Does the GN21050 sheet allow 50c at the rear with 700c wheels?
No. Its listed 700c rear entry is 45c, while the front entry is 50c.
Are the 650b rear and front entries identical?
No. The document lists 44c rear and 50c front for 650b.
Does a mudguard mount prove a chosen tyre and guard will fit together?
No. Mounting provision and the clearance of the installed combination need separate checks.
Sources
GN21050 page 2 gives different front and rear clearances for both listed wheel formats; page 1 separately identifies the original 700x40c tyre options. 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
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