Neville hike rating formula  We use this rating in addition to the subjective ratings of Mr. & Ms. average. If the formula confuses you then
all you need to know is the higher the number the more difficult the trail. Find a graded trail that you or a friend have allready done and
compare that trails rating with your experience. All Graded trails are listed here.
G = [Df + Ff] * [tW + (k * tC)] / 4

Where in:
G = Grade points for the hike
Df = Day factor
Where a: 
1 day hike = 0.11
2 day hike = 0
3 day hike = 0.11
4 day hike = 0.22
Add an additional 0.11
for every extra day thereafter

Ff = Facility factor
Where a: 
Hutted day walk (from one central hut) = 0.5
Multi hutted set trail = 1.0
Tented (carry your own tent) set trail = 1.3
Wilderness area (own route with tents) = 1.5

tW = Total hike distance in km
k = Constant factor of 0.0133
tC = Total of all ascents in metres

EXPLANATION
An explanation of the factors and constants
used may help to explain the logic (right or wrong) of the formula.
The basis of the formula is an average
person doing a 2 day hutted trail.
It has been assumed that a basic load for this hike would
be 10kg plus 1kg per day for food, therefore a total of 12 kg.

Ff  FACILITY FACTOR
Basic load as before equals 12 kg
It is assumed that no additional equipment or weight
is required for a hutted route therefore that is the base factor of
1.0.
If the trail consists of day walks
from a central hut there should be no requirement to carry all your
kit, only the basics of food and water for the day plus the survival
items of warm or wet weather clothing, 1st Aid kit, etc.
Therefore for this type of trail the factor is assessed as:
12kg  6kg /12kg = 0.5
If the trail is a tented route then
quite apart from the additional weight of the tent itself (either total
or as a split load) there are additional items of stoves, pots, sleeping
mattresses, lamps or torches, fuel etc.
This additional weight has been assumed as 3.5kg and therefore the factor
is assessed as:
12kg + 3.5kg /12kg = 1.3

k  CONSTANT
This constant is intended to equate
the metres climbed over the hike to an equivalent number of kilometres
of fairly flat walking.
It is widely written that for every 1 000'
(300m) of ascent then one should allow for one hours extra walking time.
Assuming that a comfortable flat walking speed equals 4km per hour this
means that a 300m climb is equal to 4km.
Therefore:
1m climb = 4.0km /300m = 0.0133km

SUMMARY
As I hope you now understand, I have tried to reduce the hike, taking
into account the additional weight etc, to an equivalent number of kilometres
of flat walking. The reason for dividing the total by 4 is two fold,
firstly it gives a reasonably sized number for the grade and secondly
by dividing by 4 should give a number that, if my theories are correct,
is the same as the number of hours walking time.
John Neville
Tel: +27 (0)12 9933531
Email: c/o johnn@airports.co.za

