Brompton Dynamo Axle Hardware: Identify the Complete Historical Set

Brompton dynamo axle hardware is a complete-set question when working with the historical hollow-axle hubs in the manufacturer's January 2012 sheet. The bolt, bush and nut were revised together. Recognising that revision is more useful than buying a bolt that appears close in length, especially when a wheel or its fastening parts have been replaced independently.

Brompton dynamo axle hardware before and after the revision

The January 2012 hub-dynamo fitting sheet (https://trade.brompton.com/Uploads/QPart/QPart-Datasheets/ds-dynoset-hub.pdf) labels the old bolt as 100 mm and the new bolt as 102 mm. It says the revised set was used on bikes from 2010 onwards, with a slightly larger bush and nut. The dimensions identify the historical sets; they are not a claim that every later Brompton uses this fastening arrangement.

Within that document's scope, the new larger set can be used with Brompton hollow-axle hubs regardless of age, but the old smaller set must not be used with the Shimano F703 dynamo hub. Brompton warns that an incorrect set may leave the front wheel insecure. A familiar hub shape or an apparently engaged nut is not an adequate substitute for identifying the set.

Include the washers and folding hardware in the enquiry

The sheet illustrates separate right- and left-hand tab washers and a hook wire-form on the left. It also notes that some P-type bicycles need a special right-hand washer to protect control cables when folded. These details explain why a loose bolt alone is incomplete evidence when a workshop is trying to reconstruct a missing assembly.

Provide the hub model, photographs of the retained hardware and a record of what was changed or lost. Ask for confirmation of the complete approved set and the appropriate washer arrangement before the bike returns to use. If lighting cables were disturbed during wheel work, use the historical loom-routing guide to prepare the separate cable-clearance questions.

Do not treat a collection of loose parts as a verified set just because each item appears in a photograph of one. The manufacturer describes a revision involving three associated pieces, with a specific exclusion for the older assembly. Keep the retained pieces identifiable for the dealer, and ask which belong together. That question remains necessary even when a previous owner says the wheel worked before it was removed.

FAQ

What lengths identify the two illustrated bolts?

The January 2012 sheet shows 100 mm for the old set and 102 mm for the revised set. It also changes the bush and nut, so length is not the whole specification.

Can the old small set be used with Shimano F703?

No. The manufacturer explicitly excludes that combination and warns that using the wrong set can leave the front wheel insecure.

Is a general modern axle bolt an equivalent replacement?

The sheet documents particular historical Brompton hardware. It does not approve unrelated axle systems or establish a current replacement merely from a matching nominal length.

Take a complete hardware inventory to the dealer rather than an isolated bolt measurement. Other classic-bike decisions are collected in the Brompton owner topic; keeping fastening and electrical questions distinct makes both enquiries more precise.

Photograph credits and permissions

Photograph 1

Original title: Brompton bicycle half folded and loaded

Creator: Bossphotography

Original source URI: https://commons.wikimedia.org/wiki/File:Brompton_bicycle_half_folded_and_loaded.jpg

License / permission: CC0 1.0

License / permission URI: https://creativecommons.org/publicdomain/zero/1.0/

Modification notice: Original photograph reproduced without alteration.