Marin Four Corners 2 bottom bracket: prepare a useful crank-service enquiry

Marin Four Corners 2 bottom bracket identification begins with the manufacturer's specific build record. The page used here lists SRAM DUB BSA alongside an Apex 1 crank with a forty-tooth chainring. That is a better starting point for a service enquiry than the general description steel touring bike, but it does not provide every dimension or installation detail needed to order and fit a replacement.

Read the Marin Four Corners 2 bottom bracket entry in context

Keep the bottom-bracket and crank rows together when contacting a workshop. The named bottom bracket is SRAM DUB BSA, while the crank is SRAM Apex 1. The current Four Corners 1 CUES reference instead lists a Shimano outboard bottom bracket with its double crank. Sharing the Four Corners family name does not make those two component descriptions interchangeable.

Identify whether the enquiry concerns the bearing assembly, the complete crank, a damaged arm or another part. A symptom described as a crank noise is useful information for a mechanic, but it does not establish which component needs replacing. Ask for diagnosis before treating a catalogue entry as proof of a failed bottom bracket.

Add the frame size when the crank is involved

The Four Corners 2 geometry table lists crank lengths of 170 millimetres for XS, S and M, and 175 millimetres for L and XL. Include the confirmed frame size and the length marked on the installed crank in a replacement enquiry. A previously changed crank may differ from the original table, so record both the reference and the observation.

The distinction matters even when two bicycles use the same tooth count. Chainring size does not identify crank-arm length. Conversely, selecting the catalogue arm length does not establish every detail of a replacement crank's compatibility. Give the workshop the complete component identity instead of reducing the order to a forty-tooth label.

Leave unlisted dimensions and assembly settings open

The cited product table does not state the shell width, bearing-part number, spacer arrangement or tightening procedure. Do not fill those fields by assuming that the bottom-bracket family name supplies them. Have the mechanic identify the actual frame and installed parts, then consult the appropriate component documentation before selecting and installing anything.

Marin's linked 2022 general owner's manual explains that component-manufacturer instructions take precedence if they conflict with the general manual. It also directs service and repair questions to a dealer. For this enquiry, the useful result is a confirmed part and installation plan for the actual bicycle, rather than a generic removal procedure or an unverified torque value.

Crank-service enquiry FAQ

Is DUB BSA the complete replacement specification?

No. It is the named catalogue entry; the exact replacement and installation requirements still need component-specific confirmation.

Do all five frame sizes list the same crank length?

No. XS, S and M list 170 millimetres, while L and XL list 175 millimetres.

Does a noise establish that the bottom bracket has failed?

No. Describe the symptom and arrange diagnosis before choosing which component to replace.

Take the build reference, frame size and installed-part observations together to the service appointment. If the question concerns ratios instead, read gearing endpoints in the Marin collection.

• Primary reference: Marin Four Corners 2 build and geometry; content labelled 2025.
• Primary reference: Marin current Four Corners 1 CUES build and geometry.
• Primary reference: Marin adult 12th edition 2022 owner manual; physical page 2 and printed pages 34–36.