1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144 
Tighter standards bring results
Page 25
If you've noticed an error in this article please click here to report it so we can fix it.
More than 25,000 CVs are participating in the IRTE's UK wheel loss trials — and early results are very encouraging.
minate frequent checks and retorquing of the wheel nuts on all vehicles except some 1358 buses. The company has experienced wheel-loss problems with this type of vehicle in the past and the fleet engineer suspects there may be some stud yield on the rear hubs of the buses, which can run very hot.
When Pandoro began its 18month trial in August 1988 it was on a much larger scale, involving 197 tractive units and 3030 semi-trailers. Over a distance of almost 25,000,000 kilometres the fleet operated with wheel fixings increased to just over 800Nm (600Ibft). No problems were encountered on the trailer fleet. The wheels of the tractors were periodically checked to discover the 'settled' torque and this was found to be between 620Nm (4601hft) and 695Nm (5101bft) in most cases, with no loss thereafter.
Two problems
The company initially ran the trial with the wheel-nut torque on half of the units increased to over 800Nm. Two problems were uncovered. One Mercedes tractor suffered a gradual loosening of a single wheelstud to 515Nm (3801bft), though there were no other instances further of slackening. A 'control' Volvo, F10 with wheel studs tightened to only 610Nm (4501bft), lost a nearside drive-axle wheel after 100 minutes of stop/start driving in a traffic jam. On that occasion all the wheel nuts were shed cleanly with no damage. The torque on the same studs and wheels was subsequently increased to 800Nm (6001bft) and there have been no problems since.
The early results of this trial are encouraging, but more research is necessary to produce a British Standard which will reduce the dangers of wheel loss.
If you would like to support the Wheel Loss Campaign, make your cheques payable to Commercial Motor Wheels Fund, and send them to Commercial Motor, Quadrant House, The Quadrant, Sutton, Surrey, SM2 5AS.