Page 301 - Automotive Engineering Powertrain Chassis System and Vehicle Body

CHAP TER 1 0. 1 Tyres and wheels

Drop base rim DIN 7817 – 5 J 13 H2
double hump

rim diameter in inches
reference to drop base
for tyre-fitting
rim flange design

rim width in inches
number of standard
(only in Germany; can
be dropped)

Nature of safety shoulder
Denomination Outside of rim Inside of rim Identification letters
One-sided hump Hump Normal H
Double hump Hump Hump H2
One-sided flat hump Flat hump Normal FH 1
Double-sided flat hump Flat hump Flat hump FH2 1
Combination hump Flat hump Hump CH 2

1
In place of the identification letters FH the identification letters FHA were also permitted.
2
In place of the identification letters CH the identification letters FH1-H were also permitted.
Fig. 10.1-22 Marking of the various safety shoulders when used only on the outside of the rim or on both the inside and outside. Normal
means there is no safety contour (Fig. 10.1-1). Further details are contained in standard DIN 7817.

Jaw width r s , the smaller can be the depth dimension e. How-
ever, a negative kingpin offset – r s , especially on front-
Vent wheel drive, results in a significant depth e and severe
hole bowing of the attachment faces (as can be seen in Figs.
10.1-8, 10.1-23 and 10.1-25).
The wheel disc can be perforated to save weight and
achieve better brake cooling. Despite the fact that they
Hub flange
costalmost four times as much assheetmetaldesigns,alloy
Hole circle – bolt hole number Middle hole e impression and 10.1-24). Their advantages are:
Rim
wheels are becoming increasingly popular (Figs. 8.1-56
lower masses;
Depth of
extensive styling options; and therefore
better appearance;
processing allows precise centring and limitation of
the radial and lateral runout (see Section 10.1.5);
good heat transfer for brake-cooling.
Fig. 10.1-23 The sheet metal disc-type wheel used in series
production vehicles consists of a rim and disc. To avoid fatigue Often incorrectly called aluminium rims, alloy wheels are
fractures, the wheel hub flange diameter should be greater than mainly manufactured using low-pressure chill casting,
the dish contact surface. Wheel offset e (depth of impression) and occasionally forging or aluminium plate, and generally
kingpin offset at ground r s are directly correlated. A change in e consist of aluminium alloys with a silicon content (which
can lead to an increase or a reduction in r s . The dome-shaped
dish leading to the negative kingpin offset at ground is clearly are sometimes heat hardenable), such as GK-Al Si 11
shown (diagram: Hayes Lemmerz). Mg, GK-Al Si 7 Mg T (T ¼ tempered after casting) etc.

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