Playbook, bike shop
Standards the shop can state, on a bike it cannot see
The bike trade has more competing standards for the same joint than almost anything else sold in a shop, which means a part can enter a frame perfectly and still be wrong. The specification of the part is published. The specification of the customer's bike is not, because model year, build level and whatever a previous owner fitted have all moved it since it left the factory.
Why this is not the general answer
The handling pattern for compatibility questions holds across every trade. What follows is the part that does not.
- The specification of the part is published and the specification of the rider's bike is not, because model year, build level and whatever a previous owner fitted have all moved it.
- This trade carries more competing standards for the same joint than almost any other, so a component that physically enters a frame can still be the wrong one.
- Several of the deciding facts are only visible with a wheel out or a crank off, which is a counter conversation rather than a chat one.
- A wrongly sold component is not simply a return, it is a refit and a lost workshop slot, so the shop has a direct interest in the assistant declining to conclude.
How it arrives
- will this cassette fit my bike
- what bottom bracket do i need
- is this compatible with 11 speed
- will this fit a 12mm thru axle
- can i put a wider tyre on this frame
- does this brake work with my levers
What has to be indexed for this to work
| A standards reference in plain language | Bottom bracket shells, axle standards, freehub types, speed counts, brake mounts and rotor fittings, explained as what each one is rather than as a list of names. Most of these conversations are somebody trying to learn what a standard is. |
|---|---|
| What each part you sell requires | Written as a requirement rather than as a compatibility claim: this needs that freehub, that shell width, that many speeds. Requirements are facts about your stock and are safe to state without qualification. |
| Where model years diverge | The ranges you sell where a standard changed between years, and what to look at to tell them apart. This is knowledge the workshop carries in its head and it answers a whole category of question. |
| What the workshop needs to see | Which checks need the wheel out, the crank off or the bike on a stand, and what a useful photograph looks like. Framing it as a two minute counter job makes the handover feel small rather than obstructive. |
The reply
That cassette needs a particular freehub body and a matching speed count, both of which are listed on the product page as requirements rather than as a promise that it fits yours. The catch is your wheel: freehub bodies changed on several models between years, and if the wheel has ever been replaced the original bike specification no longer tells you what is on it. The quick way to settle it is for us to look with the wheel out, which takes a minute at the counter, or you can send a photograph of the freehub with the cassette off.
It states the requirement, which is a fact, and refuses the conclusion, which is not. Naming the wheel as the unknown explains why the refusal is not laziness, and second hand wheels are genuinely the reason this question cannot be answered remotely. Offering both the counter and a photograph gives the rider a route that suits whichever they can manage.
Where it stops
The trigger. The visitor asks the assistant to confirm a part fits their bike, or the answer depends on a component that may have been changed at any point.
I can tell you what the part needs but not what your bike has, and guessing costs you a return and a refit. Bring it in, or leave your name, email and a photograph of the area and somebody will check.
It stops answering before it guesses, says who will pick it up, and asks for the one thing that makes a reply possible. Nothing about it reads as a dead end.
Never say this here
Out of bounds
- Never confirm that a component will fit a customer's bike.
- Never assume a bike is standard for its model year.
- Never say two standards are interchangeable because they share a measurement.
- Never suggest forcing, facing or modifying a part to make it fit.
Questions
- Is this worth automating if it never reaches a conclusion?
- Yes, because most of the conversation is somebody learning what a standard is. An assistant that explains freehub types or axle standards clearly saves a long counter conversation, and it still ends with the shop checking the bike, which is where it was always going to end.
- What if the rider knows their exact model and year?
- Then it can state what that model was specified with, if you have indexed it, and should still say that a previous owner may have changed it. Original specification is a historical fact about a bike, not a current one, and the difference is the whole risk here.
- How do we stop it reasoning from a shared measurement?
- Write the standards reference as what each standard is, including the pairs that share a number and are not interchangeable. If the material names the trap, the assistant repeats the trap. If it only lists dimensions, the assistant will do arithmetic with them.
Keep reading
- Everything for a bike shopFrame sizing, service turnaround and whether a part fits are the daily questions. Safety critical repair advice is an escalation.
- Handling compatibility questions in generalAnswerable only if you publish a list. Inferring compatibility is the failure, and the price of a wrong yes is a return and a refund.
- Size charts, geometry and the gap a bike fit closesHeight puts a rider in a band and no further. Reach and stack move it, which is why a bike fit exists as a service.
- Stop riding it: the handover that begins with an instructionThe first line of the reply is an instruction to stop riding. The handover comes second, because a soft brake will not wait for email.
- Stock in a bike shop is a grid, and size is the axis that mattersHaving the bike is not having it in the size that fits. Floor stock, allocation from the brand, and why a restock is a season not a date.
Try it on your own material
Upload a document or point it at your site, paste one line of HTML, then ask it something only your business could answer.