GB/T 9769-2015 Rim contour measure
1 Scope
This standard specifies the terms of rim contours, measurement positions and items for contour shapes, as well as the design and usage of ball tapes, flat tape and gauges.
This standard is applicable to the measurement of the following rim contour shapes:
5° drop center rims (5° DC), 15° drop center rims (15° DC), semi-drop-center rims, 5° flat base rims (5° FB), and full tapered bead seat rims.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2933 Vocabulary, designation and marking of wheels and rims for pneumatic tyres
3 Terms and definitions
For the purpose of this document, the terms and definitions given in GB/T 2933 apply.
4 Rim contour dimension designations
See Figure 1 for the rim contour dimension designations.
Key:
A—specified rim width; P—bead seat width;
B—flange width; R1—flange joint radius;
C—flange radius position dimension; R2—flange radius;
D—specified rim diameter; R3—bead seat arc radius;
DF—bead seat flat peak diameter; R4—well top arc radius;
DR—bead seat round peak diameter; R5—well bottom arc radius;
F1, F2—valve hole position dimensions on rim; R6—flange edge fillet radius;
G—flange height; R7—well side arc radius;
H—well bottom depth; V—dimension of valve hole or valve slot;
L—well bottom width; α—well bottom angle;
M—well position dimension; β—bead seat angle.
Note 1: Dimensions marked with * are related to the mounting and dismounting of tire on the rim, and they are the minimum dimensions of the rim well bottom shape, and M represents the limiting position dimension of the well bottom.
Note 2: The well top arc radius, R4, and the well bottom angle, α, are important parameters for mounting and dismounting tire on the rim.
Note 3: Mounting side, that is, the tire will be mounted into or removed from the rim from this side. For a multi-piece rim, the mounting side is on the side from which the flange can be dismounted.
Figure 1 Rim contour dimension designations
5 Rim contour measurement positions
See Figure 2 for the rim contour measurement positions.
Figure 2 Schematic diagram of measurement positions for rim contour shape
6 Measurement items
6.1 Measurement items for rim diameter
Bead seat diameter (specified rim diameter)—measured with a ball tape.
Peak diameter (round peak, flat peak)—measured with a flat tape.
6.2 Measurement items for rim contour shape
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Rim contour dimension designations
5 Rim contour measurement positions
6 Measurement items
7 Measurement tools and usage methods (for 5° DC drop center rim contours and 15° DC drop center rim contours)
8 Measurement of contour dimensions of semi-drop-center rims
9 Measurement of contour dimensions of 5° flat base rims and full tapered bead seat rims
10 Measurement of valve holes
