Claims
- 1. In a radial tire having an aspect ratio of up to 50%, a run-flat pneumatic radial tire characterized in that:
- a reinforcing lining layer having a complex modulus at 20.degree., (E*.sub.20), of at least 16 MPa, a ratio of a complex modulus at 100.degree., (E*.sub.100), to said complex modulus at 20.degree. (E*.sub.20), that is, E*.sub.100 /E*.sub.20 of at least 0.80, a 100% modulus of at least 60 kg/cm.sup.2 and a loss tangent (tangent .delta.) at 100.degree. C. of up to 0.35 said E*.sub.20,E*.sub.100, and loss tangent at 100.degree. C. being measured under conditions of a frequency of 20 Hz, an initial strain of 5% and a dynamic strain of 1% elongation, and having a crescent sectional shape is disposed inside a carcass layer at sidewall portions in such a manner that one of its end portions overlaps with the end portion of a belt layer of a tread portion and the other end portion overlaps with a bead filler of said bead portion;
- said bead filler of said bead portion being made of rubber having a JIS - A hardness of from 60 to 80 and has a height h of from 28 to 33 mm from a base adjacent a rim of said tire in a direction vertical to the axis of rotation of said tire; and
- said carcass layer consisting of inner and outer two layers, said inner carcass layer is turned up from inside to outside said tire around said bead core so that its end is positioned at a position higher than the height h of said bead filler and an end of said outer carcass layer is disposed axially outward of said bead core; wherein said outer carcass layer is also turned up around said bead core from inside to outside said tire so that said outer carcass layer is on an outer side of said bead core with said end of said outer carcass layer disposed directly adjacent said bead core.
- 2. A run-flat pneumatic radial tire according to claim 1, wherein the thickness of said reinforcing liner layer having a crescent sectional shape is the greatest at the center portion and decreases gradually towards the upper and lower portions in the radial direction of said tire.
- 3. A run-flat pneumatic radial tire according to claim 2, wherein the maximum thickness of said reinforcing liner layer at the center portion is from 3 mm to 8 mm.
- 4. The run-flat pneumatic radial tire according to claim 1, wherein said reinforcing lining layer is made from a rubber including at least one rubber selected from the group consisting of polybutadiene rubber and syndiotactic butadiene rubber.
Priority Claims (2)
Number |
Date |
Country |
Kind |
1-231674 |
Sep 1989 |
JPX |
|
2-170120 |
Jun 1990 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 564,527 filed Aug. 9, 1990, U.S. Pat. No. 5,131,445.
US Referenced Citations (3)
Foreign Referenced Citations (3)
Number |
Date |
Country |
3-143710 |
Jun 1991 |
JPX |
1423401 |
Feb 1976 |
GBX |
2138367 |
Oct 1984 |
GBX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
564527 |
Aug 1990 |
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