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Bike Fitting on a Purely Custom Fitbik allows Garry tooptimisethe individual parameters of fit required to find the optimum bike position for his clients from Glasgow, Edinburgh and all over Scotland.

The Purely Custom Fitting Jig shown above is a state of the art sizing bike that I use for custom Frame designs where the client wants millimetre precision in their fit before buying a made to measure bicycle. They want to know which pedals to choose, which handlebars to buy, what is the ideal saddle for them and also an ideal crank length, but critically without the guesswork. This Jig allows me find all of those things with ease.

But it's more than just that.. I use it for saddle fitting services where changing saddles takes seconds not minutes, Triathlon Bikefits, Frame Finder Fits, Time Trial or TT Fittings and I also use it to work out the ideal crank length for a rider relative to their position on the bike and what they are trying to achieve on it.


Changing cranks is an expensive business. Here it can be done in 2.5mm increments and it takes seconds to do. All the while the jig is feeding back torque analysis relative to the changes.


Adjustable cranks offer Garry the ability to find th optimum crank length for every rider he bikefits here in Glasgow, Scotland.


Computrainer resistance unit offers resistance, torque angle, power in watts, spinscan and pedalling efficiency. An extremely capable an high end resistance unit utilised by the best bike fitters.


As we can see below, the laptop provides some key elements of information.

These include...

  • Right/Left balance (or power split).

  • 'Spinscan' which is measuring your pedalling efficiency.

  • Average torque angle (ATA) which is the average point relevant to top dead centre that you begin the downstroke of the pedalling action.


The data feeds back in real time and whilst useful - it isn't the be all and end all of all things bike fitting. A quality bikefit is when the fitter uses data such as this in a complimentary fashion and NOT to actually fit the person to their bike.

Garry Kirk Bike Fitting Purely Custom Fitbike in action. The ultimate bikefit in Scotland.
cycling analysis performed by garry kirk during evry fully comprehensive bikefit in Glasgow.
coputrainer spinscan, cycling analysis, cycling data for the optimum bikefit in scotland.
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