BuildMyMTB
Prototype - Evolving Daily

Box One Single Speed Aluminum Cog (13T) Rear Cog

What the checker says18will not fit2check before you buy

Run variant by variant through the BMX builder’s own engine. Every sentence below is the checker’s, unedited. Nothing here says this part fits your bike; it says what it does and does not fit among the parts we hold.

Checked against 653 verified BMX parts in this catalog. 632 produced no finding of any kind.

Will not fit

    Bmx cog driver, Rear Wheel / Hub. 18 more findings from the same check, on up to 1 of the 52 verified rear wheel / hubs each.

    Open a variant in the builder to see the ones that apply to your own parts.

    Check before you buy

    • Check before you buywarning · SprocketChain width mismatch: Sprocket = 3/32in, Rear cog = 1/8in. Sprocket, cog and chain should share one width class (1/8in or 3/32in) - a mixed stack runs but skips and wears fast. On 2 of the 18 verified sprockets in this catalog.
    • Check before you buywarning · ChainChain width mismatch: Rear cog = 1/8in, Chain = 3/32in. Sprocket, cog and chain should share one width class (1/8in or 3/32in) - a mixed stack runs but skips and wears fast. On 1 of the 21 verified chains in this catalog.
    The checker compares the dimensions listed in what we check, and what we don’t. “No conflicts found” means no conflict among those dimensions — not a guarantee that a build works. Errors mean it won’t fit; warnings mean it works but check; infos are notes.

    $29.99 MSRP·8 g

    What the maker states

    Teeth
    13 teeth
    Fits driver
    Fits a cassette driver
    Pitch
    1/8"
    Source

    Source: the maker’s page. Last checked 2026-08-19.

    Checked against

    The checker ran this model against every verified part below that it has a slot for, the same way it checks a build in the builder. What follows is the verdict it actually produced for that specific pairing — not a recommendation, and not a guarantee any of these parts fits your own bike.

    6 of 511 counterparts with a page of their own that the checker actually probed this model against, in alphabetical order by brand and model — never by price, popularity or the verdict itself.

    Where this sits

    Box One Single Speed Aluminum Cog (13T) is the first model on that list.Next: Box One Single Speed Aluminum Cog (14T)All Box rear cogsOpen a variant in the builder to see the ones that apply to your own parts