stock frames:

The vast majority of bikes and frames sold by manufacturers are 'stock' or preset in a range of sizes. Some are in smaller 1cm increments so the chance of a good fit is realistic (as long as your physiology and aspiration fits with the manufacturers original design intentions). And some manufacturers offer bikes in frames in a size run from XS (Extra Small) in a limited run to XL..etc. The 'stock' conundrum is not helped at all by the fact that manufacturers all measure their bikes in a different way so a Ridley '56' is nothing like a Trek '56'. Or by the fact that most manufacturers have very little to say about how their products 'fit' or should be calibrated to the end user (you). When a manufacturer conceives a range of bikes they have no idea who the end user will be. They have to design a frame that will withstand someone who weighs 150 kgs but still feel good to someone who is 50kgs. Common sense should tell us this is implausible.   

CUSTOM BUILD UP?

This where a criteria-specific stock frame is built into a complete bike using a groupset components that are selected to help achieve a more efficient and precise set-up. Bar-width/reach, crank-length, stem-length, saddle..etc should all be thoughtfully reviewed in this process. Much better by definition than stock but not quite 'full-custom' (below). For many shops this is the pinnacle of custom. But there is another level....

full custom:

This means starting with a cyclist and a blank sheet of paper. A two hour CycleFit (or similar) bike-fitting session is used to both understand every detail of someone's cycling history, physiology and aspiration. The session painstakingly circles the final equilibrium of an individual's biomechanical perfection. After which an evaluation of possible materials and material combinations matches considerations of stiffness, lightness, durability and aesthetics - steel, titanium, titanium/carbon and carbon are all discussed. After which Jules or Phil draft the custom frame and create a CAD to show the finished frame archicture. The drafting process not only ensures that there is no compromise in terms of final position but also that there is perfect weight-distribution on the built bike to guarentee perfect riding dynamics. In drafting process it is possible to consider and reflect individual choice at the conception stage e.g:

Bottom-Bracket Height - Higher for more pedal clearance, sharper handling and dynamic lean-angles. Lower for more stability, confidence, lower centre of gravity and consequent feeling of security.

Chain-Stay Length - Shorter for ultimate power-transference, drive-chain stiffness, fast handling and twitchy descending. Longer for more stability, drive-chain compliance.

Head-Angle / Trail / Rake - Dramatically affects the ride and overall handling of the finished bike. Must be finely tuned to rider physiology, experience and taste.

We have drafted numerous frames and also design the Pearson stock geometry. Once the design has been approved they will liaise with the factory to discuss the desired ride outcome for the project. The factory will then make an optimal tube selection to balance optimal dynamics, minimal weight and frame longevity.

The final outcome should be a ride that lets the rider perform at their most efficient level to achieve maximum performance at minimal effort and maximum comfort. It should release the rider to achieve their goals with maximum injury protection. There should be no compromise.

We custom design and build bicycle frames at Pearson CycleFit with Guru and Serotta.