[SystemSafety] Wheel detachment from a moving car

[Chris Hills]

Hi  David 

I have an answer it's "data free" but...

I live in a small town in England and 
Given 
The number of tyre/breaks/exhaust places (approximately 10 and they have
multiple bays) with a steady stream of vehicles all day, 6 days a week,
having tyres/breaks done that require the removal and replacement or wheels
AND
the number of local service garages (>14) that also replace wheels, but to a
lesser extent.
AND 
A smaller number of people (and RAC/AA) who change wheels due to punctures 

Multiply this by all the towns in England (averaging out the big
towns/cities and the very small ones) and you have a vast number (it has to
be well into the thousands) of wheels being replaced every day in England. 

I think had there been any real problem in the numbers of wheels coming
loose it would be well known problem.  Thus locking wire and or cotter pins
would be required.  Especially after the last 100 + years of increasing use
of motor vehicles. 

Certainly the RAC/AA  roadside teams would be using a locking fluid on their
roadside wheel changes if either organisation saw any problems at all....
The Same would apply to the major chains of Tyre/break concerns such as ATS
As none of them do I can only conclude that there is no significant problem
with wheels coming loose. 

Regards
 
Chris 

-----Original Message-----
From: systemsafety-bounces at lists.techfak.uni-bielefeld.de
[mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of
David Crocker
Sent: 21 May 2015 15:26
To: The System Safety List
Subject: [SystemSafety] Wheel detachment from a moving car

My partner has a nasty near-accident on Tuesday. While travelling on a dual
carriageway at 60mph, she became aware of a new noise from the vehicle.
Shortly afterwards, the front nearside wheel detached and she saw it roll
into an adjacent field. Fortunately the car did not tip over. She is a
skilful driver, so she allowed the vehicle to decelerate without using the
brake. She was not rear-ended, and when at a slow speed she drove it into
the adjacent grass verge. She was shaken but unharmed. The car is beyond
economic repair because the steering assembly and other parts are wrecked.

She had driven 500 miles since having the tyre on that wheel replaced.

This got me thinking:

1. How often do wheels detach from cars while travelling? Are there any
figures recorded? Have any fatalities occurred as a result?

2. Why is there no requirement on manufacturers and fitters to use locking
wire, a cotter pin, or some other mechanism to ensure that the wheel nuts
cannot come off? I notice that some HGVs do use locking wire on the wheel
nuts.

--
David Crocker, Escher Technologies Ltd.
http://www.eschertech.com
Tel. +44 (0)20 8144 3265 or +44 (0)7977 211486

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