FLEX

The following charts show the relationships between Flex and deck thickness
and deck mean width.
NB  Very small differences in deck thickness with give massive changes in flex.
However the width to flex relationship is linear and gives small changes.
Hence fine tuning of the deck is possible by just cutting down the width.
If the deck is too narrow the torsional rigidity will suffer unless the layup
has been specifically done with this in mind.
The calculations make many assumptions for simplicity and should
only be used as a rough guide.
Remember once cut you can't go back!

Flex is measured on CKB decks by loading it with a known weight
at the centre of the span on a level fixed surface and measuring the
resultant deflection from the un-loaded position.
The weight(in Kilos)  is divided by the deflection(in mm) to give a guide
to the decks stiffness under bending.
Pop is the decks ability to return energy when dynamically loaded.

Different grades of carbon will require different thicknesses to give the
same flex. Higher modulus UD carbon will need less deck thickness than
a woven type.

Chart showing flex in Kilos/mm against deck thickness for a range of
early version Carbon and Carbon/Glass decks ( with an 11mm thick
Trampa for comparison on the far right).

(click on image for enlargement)

As a rough guide
> 6.0      Kilos/mm for heavy riders
5.0 - 6.5 Kilos/mm for medium weight riders
4.0 - 5.5 Kilos/mm for light weight rider
(but this will depend on individual preference for flex as well)

Latest series of decks Flex comparison LB40-43 of flex Kilos/mm against mean width.