About
Why builds.bike exists
I've spent years building and fixing my own bikes, and just as many years getting burned by parts that were supposed to fit and didn't. Cassette bodies, bottom bracket standards, brake mount types, hub spacing: the failure mode is always the same. You find out you guessed wrong after the part shows up.
The problem
Compatibility information for bike parts is scattered across manufacturer spec sheets, forum threads, and word-of-mouth, and a lot of it is wrong, outdated, or missing the one dimension that actually matters for your build. Forums are unreliable because answers age out as standards change; spec sheets are correct but buried and hard to cross-reference against a part you don't already own. There wasn't a single place to check "does this actually work with that" before you spend the money. So I built one.
How the compatibility engine works
builds.bike checks part pairings against a catalog of verified specs and known mechanical standards (freehub types, cable pull ratios, axle spacing, mount standards, and more) and returns a verdict with the reasoning behind it, not just a yes/no. Every check comes with a confidence level, so you can see when the answer is well-established versus when it's worth double-checking yourself before you buy.
I'd rather tell you "we're not sure" than give you a confident wrong answer. Wrong compatibility calls are exactly the kind of mistake this tool exists to prevent, so reliability gets prioritized over covering every obscure or vintage part on day one.
Who's behind it
builds.bike is built and run by Zach, currently a solo operation handling product, engineering, and support. Questions, bug reports, or a pairing that came back wrong all come straight to me.
See it in action
Check a pairing yourself, or spec a full build and let the engine flag conflicts as you go.