METHOD · DIFFERENCES IN SCOPE
Two riders ask for a bike fit and pay a similar figure. One is measured for twenty minutes and gets the saddle raised. The other has strength per leg, joint ranges and segment lengths recorded before the bike moves at all. Both leave with a receipt that reads the same, and only one of them knows why their position is what it is.
Choosing a size, adjusting a bike and assessing a rider are three different questions.
The three questions
The depth of an intervention does not follow from the word that names it. It follows from what is assessed, who interprets it, which instrument is used and whether the change is verified afterwards.
Dimensions
Which bike, size or geometry is compatible with this person?
The fit between a person and a frame.
What it does not resolve: It does not say how your body behaves while pedalling, or why something hurts. It can be digital, automated and very precise, and still be dimensioning.
Adjusts
How should this bike be configured for this rider?
The interaction between the rider and the bike they already own.
What it does not resolve: Its depth varies enormously: two services advertised under the same word can last twenty minutes or three hours. The commercial name tells you nothing about the scope.
Assesses, interprets, intervenes and verifies
What can this body do, and which configuration follows from that?
First the cyclist as a biological and mechanical system. Then the interaction with the bike.
What it does not resolve: It is not a label you earn by buying a device. Without history taking, functional measurement and a later check, it remains a well-instrumented adjustment.
Why the instrument does not decide
A laser reference aligns a cockpit just the same whether the work is sizing a frame, adjusting a position or verifying an intervention made two months ago. The photograph does not tell the three processes apart, and neither does the receipt. What tells them apart is the question asked before the equipment was switched on, and whether anyone opens that same measurement again once you have ridden the new position.
The short version
Technology can take part in all three. A simulator, a laser, a sensor or a trained model serve dimensioning as readily as assessment, and owning them does not by itself determine the depth of the process. What determines it is the question asked before the machine is switched on.
Technology measures. Training allows interpretation. Method integrates. Verification demonstrates.
Side by side
| Criterion | Bike sizing | Bike fitting | Biomechanical assessment |
|---|---|---|---|
| Object of study | The frame and its compatibility with a set of body measurements | The bike you already own and its contact points | The cyclist first, the bike second |
| Typical moment | Before buying | After buying | Either, depending on what limits the case |
| What is measured on the body | Lengths and proportions | Position and, depending on scope, basic mobility | History, posture, mobility, strength, anthropometry and movement |
| What it produces | Size, compatible model and a starting configuration | An adjusted, reproducible configuration | A diagnosis, a reasoned intervention and a verification |
| How it is checked | Checked when the bike is built | Checked during the session itself | Measured again afterwards, under the same protocol |
| ONE service | BIKEFINDER 3D · GURU | Included within BIKEFIT 3D | BIKEFIT 3D · GURU, with the body assessment first |
The table describes processes, not providers. One professional can offer all three, and a case commonly starts in one and ends in another.
Which one applies
Diagnosis One reviews your goals and history, then explains what to assess and why before you book a service.
Choose how to start
Frequently asked questions
Not necessarily. The instrument does not define the category of the process: what defines it is what gets assessed, who interprets it and whether the change is verified afterwards. A bike sizing can be digital, automated and very precise at dimensioning, and still answer the sizing question, which is about compatibility rather than function.
It is, and for many riders it is exactly what they need. Someone without symptoms who changed saddle and wants their height back does not need a full functional assessment. The problem is not that short adjustments exist: it is that they are advertised under the same name as a process four times longer, so anyone comparing two quotes cannot tell what they are comparing.
No, and ONE does not claim otherwise. There are fitters without university training who have excellent judgement and many hours of craft. What training changes is what can be interpreted: reading a strength asymmetry, a limited joint range or a previous injury and deciding what to do about them takes a base that is not improvised. The bounded claim is this one: not every bike fit constitutes a biomechanical assessment.
With four questions: what is measured on the body before the bike is touched, who interprets those measurements and with what training, whether the change is tested under load or only at a standstill, and whether there is a later check against the starting measurement. All four can be asked in writing before booking, and they separate more than price does.
