Who I am
I'm Dave. I've spent 12 years running professional workshops — servicing, repairs, wheelbuilding, custom builds, and answering the same question hundreds of times: “will this part work with what I've got?”
That question sounds simple, but the answer rarely is. Shimano alone has changed its road rear derailleur pull ratios three times. GRX use either road or mountain cassettes, depending on which rear mech you fit. A brake lever designed for one caliper will give you the wrong lever feel on a different one. And every year the manufacturers add more standards, more exceptions, and more ways for well-meaning cyclists to buy the wrong part.
Why I built this
I got tired of watching people waste money on parts that don't fit. Forum advice is hit and miss. Generic AI chatbots confidently give wrong answers because they don't understand the actual mechanical constraints — they pattern-match from text, not from how the parts physically interact.
Bike Parts Guru is different. The compatibility engine is rules-based, built on real mechanical knowledge from years of workshop experience. Every rule reflects how components actually interface — cable pull ratios, freehub spline patterns, axle standards, rotor mount interfaces, and all the edge cases that only surface when you actually try to fit the parts together.
It's not AI guesswork. It's a mechanic's knowledge, structured into a system that can check thousands of compatibility combinations in real time.
What makes it reliable
- Rules, not guesses. Every compatibility check is backed by a specific rule with a defined confidence level. If the data isn't there, the system tells you — it doesn't make something up.
- Real specifications. Component data comes from manufacturer specs and verified product pages, not user-submitted wikis or scraped forum posts.
- Dimensional matching. The engine checks actual physical dimensions — cable pull per shift, cog spacing, axle width, rotor mount pattern — not just brand and model names.
- Conservative by default. When rules conflict, the system gives you the most cautious answer. A false “compatible” is worse than a false “incompatible”.
For retailers and developers
If you run a bike shop, publish cycling content, or build tools for cyclists, the compatibility data behind Bike Parts Guru is available as an API and embeddable widget. Visit the business page for details.
Get in touch
Got a question, spotted an error, or want to suggest a feature? I'd like to hear from you.