2. Polyester Tyre Cord Application in Bicycle Tyre
S P Pandey
Sr. Vice President (Technical)
Ralson (India) Limited

3. Introduction
The main objective of this presentation is to replace Cotton fabric by Polyester fabric as casing material in cycle tyre manufacturing with Monoband building machine at comparative cost and better performance
Polyester tyre cord is more popular in PCR Tyre due to its known advantages. We have extended its application to Cycle tyre as Re-enforcing material.
Bicycle tyres are manufactured mainly with Cotton & Nylon 6 fabric as casing material.
Cotton tyre is still popular in India due to cost effectiveness. But there is inconsistency in Quality of Cotton Yarn.
In between Cotton and Nylon, Polyester is a good candidate to be used as casing material, Which has added advantage over cotton yarn.

4. Advantages of Polyester Cord
Lighter Weight
Cheaper to Nylon
Stronger Casing
Does not exhibit Flat spotting
Better Performance than Cotton
Reduced deformation/ Growth in service
Excellent Dimensional Stability
High productivity due to high MP (260⁰C) (may be used at elevated temperature)

5. Chemical Structure (C10H8O4)n PET
Polyester used, as casing material for tyre is commonly referred to Polyethylene Terephthalate (PET).
It contains Ester functional group in their main chain.
PET
(C10H8O4)n

6. Physical Properties SR.NO PARAMETER UNIT COTTON YARN 2/2/14 NYLON
840 / D-1
POLYESTER
1000 D/1 1
Breaking Load
Kg (Min)
2.5
5.0
7.5 2
Break
% (Min) 10 19 13 3
TEX
Gms/km - 4
Twist
Turn/Inch 5
C/V Twist
(Coefficient of Variation)
% (Max) 6
Moisture
1.0
0.8 7
Thickness
(mm) 8
Denier (Dipped)
Gm/Km 9
E.P.I
Nos 23 20
Hot Air Shrinkage
3.5
2.0 11
Dip Pick Up
%(Min)
4.5 12
Stiffness
N/10 Cord
3 – 4
Tread To Ply Adhesion
Kg/Inch (Min)
4.0 16 15 14
Ply To Ply Adhesion
No Separation

7. Typical Characteristics of Dipped Cord
Nylon 6
Polyester
Cotton
(Un Dipped)
Thermal Shrinkage %
<4.5
<1.7 -
Dip Pick Up
% Min
4.5
3.5 – 4.5
H Adhesion Force (N) 91 72 45

8. Comparative Consumption Size - 28x1.1/2
Sr. No
Cotton/Tyre
(gm)
Nylon/Tyre
Polyester/Tyre 1 79 38 41

9. WHEEL ENDURANCE TEST:-
As per BIS Standard (IS-2414 – 2005)- Size – 28x1.1/2
Stage
Load
( kg)
No. of Hours
(Min)
Inflation Pressure (P.S.I)
Actual Hours Running
(Avg)
Cotton
Nylon
Polyester 1 86 7 60 48
100 57 2 93 16 3 24
Total 47

10. WHEEL ENDURANCE TEST:-
As per BIS Standard all Cycle tyre should run minimum 47 hours at above load irrespective of Cotton , Nylon or Polyester

11. WHEEL ENDURANCE TEST:-
At Constant Load (Clit Type Machine)
Hours Running
Cotton
Nylon
Polyester
70 kg 24 km / hours speed
10-12 Hours
75-80 Hours
18 – 20 Hours
Zigzag Type Endurance Machine

12. Conclusion
Till recent past Polyester fabric was being extensively used in PCR tyre as casing material.
Now Polyester is being used as casing material replacing Cotton in bicycles tyre to provide better product to user.
Polyester tyre provides about 1.5 times more life than cotton tyres.
Small manufacturer can also afford to use polyester and make tyre on monoband machine.
Hot air shrinkage and Cord Stiffness are important for better process control.

13. Conclusion
Processing may be cheaper (No Creel and combing operation needed).
Drive Comfort– Due to lighter weight (Low Rolling Resistance).
This is an innovative approach to introduce Polyester tyre cord in Bicycle tyre range in India. Which is well accepted in the market.
Polyester tyre is better alternative to cotton tyres.

14. Thanks