14
If the top extrusion is shorter than 400 mm (15 3/4”), the joint
will be too near the top. In this case replace the uppermost full-
length 2400 mm extrusion with the 2000 mm extrusion. In this
way the joint is moved 400mm (15 3/4”) down the stay. Adjust
the C and D measurements as follows:
Deduct 400 mm (15 3/4”) from the C measurement.
Add 400 mm (15 3/4”) to the D measurement.
-
1. Insert the length of the new forestay wire (WL) as calculated in
table 1
into
table 2
, in the row
marked WL.
2. Calculate the number of full length extrusions and the length of the top extrusion.
Fixed deduction (A+B):
C+D=
3.6.1
WL
A+B
C+D
C
D
Max. number of 2400 mm (7’ 10 1/2”) extrusions which together are
shorter than C+D: [ ............ x 2400 = C ]
C=
Length of top extrusion =
The top extrusion is normally cut from the 2000 mm extrusion.
Round the edges of the cut end using a file.
Ø 4 mm wire: E = D – 120 mm (4 3/4”)
Ø 5 mm wire: E = D – 120 mm (4 3/4”)
Ø 6 mm wire: E = D – 200 mm (7 7/8”)
Cut the distance tube for the top extrusion in accordance with
the following fixed deduction:
E
Deduction:
Length of distance tube E =
-
=
Table 2: Calculation of luff extrusion length
Length of new forestay wire (as per Table 1)
Your
extrusion
Example
Ø 5
-
1395
=
1395
–
1395
(3 extrusions)
-
=
2115
=
Ø 4 mm wire: – 1340 mm (4’ 4 3/4”)
Ø 5 mm wire: – 1340 mm (4’ 4 3/4”)
Ø 6 mm wire: – 1290 mm (4’ 2 3/4”)
9.620
1
.340
8.280
7.200
1
.080
1
20
960
3.6 Calculating the length of the luff extrusion