bumpy
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| posted on 15/12/14 at 11:14 AM |
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IVA and steering wheels.
I am currently building a car which has a Mountney steering wheel on a Cortina Mk4/5 steering column. Aside from the sharpish edges I have been told
the current IVA requires a collapsible steering wheel.
Obviously a standard Mk 4/5 wheel will fit, but is it collapsible?
[Edited on 15/12/14 by bumpy]
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rdodger
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| posted on 15/12/14 at 11:35 AM |
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From the IVA Manual
An offset between the steering column and the input shaft of the steering rack or box
In cases where an intermediate shaft is used, it will be connected to the steering column at one end and the steering rack or box at the other, by
means of universal joints and/or flexible couplings. The greater the angle through which the joints run, the more effective they will be in preventing
movement being transmitted up the steering column. While it is unlikely that joints of this type will work at angles above 30 degrees, they are
unlikely to be effective if the angle between the steering column and the intermediate shaft (when viewed from the side or the top of the vehicle) is
less than 10 degrees.
A telescopic intermediate shaft
This is a common arrangement and may take the form for example of a sliding splined shaft, a sliding clamp arrangement on a non circular shaft (e.g.
triangular), or a device that permits disengagement of the upper column from the lower column.
A collapsible element in the upper column
This may take many forms. Expanded metal tubes or convoluted tubes (in association with sheer pins in the column shaft) or sliding splines are three
of the most common. These are designed primarily to allow the steering wheel and column to move away from the driver while absorbing some of his or
her deceleration if the driver were to hit the steering wheel.
Note: Driver impact against the wheel is still possible even when wearing a seat belt, particularly a fixed type rather than an inertia reel type.
Steering wheel construction
It is vital that the wheel is constructed so as to minimise the risk of facial injuries or concussion. The rim of the wheel should be padded or at
least made from a material which when deformed does not splinter or fragment. The centre boss should be padded or recessed below the level of the rim.
Wheels with a very deep dish are stiffer than flatter wheels and, as such will absorb less energy.
The centre boss will often be of a collapsible type comprising a convoluted crushable section or a series of metal fingers with a deliberate fold
introduced to initiate a collapse.
Bolts used to secure the wheel to its boss (if exposed) should ideally be flush with the wheel surface but otherwise are required to meet the radius
requirements if contactable.
Bare metal spokes are allowed as long as they conform to the edge radius requirements. Components likely to catch in the driver’s clothing or
jewellery are not permitted.
Note: It is possible to fit an 'aftermarket' steering wheel which has been approved for use on any design of column. These will be
referred to as “Separate Technical Units”. If the presenter can provide satisfactory documentary evidence that this is the case, a “Separate Technical
Unit” may be acceptable.
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bumpy
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| posted on 15/12/14 at 11:41 AM |
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"The centre boss will often be of a collapsible type comprising a convoluted crushable section or a series of metal fingers with a deliberate
fold introduced to initiate a collapse."
This is saying its not compulsory to have a collapsible wheel/boss. Is this how others read it or has anyone had a fail by not having it or indeed a
pass?
[Edited on 15/12/14 by bumpy]
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rdodger
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| posted on 15/12/14 at 11:44 AM |
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My IVA inspector looked at the collapsible boss. He didn't check if the column was collapsible which it was. It passed.
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bumpy
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| posted on 15/12/14 at 11:50 AM |
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quote:
Originally posted by rdodger
My IVA inspector looked at the collapsible boss. He didn't check if the column was collapsible which it was. It passed.
That's good. We just need to find someone who used a non collapsible wheel, to see if they got away with it.
Incidentally what column and wheel did you have?
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rdodger
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| posted on 15/12/14 at 11:53 AM |
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I used MX5 telescopic column, offset steering shaft and Momo MX5 steering wheel with centre cover.
The IVA inspector didn't check or ask about the column.
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bumpy
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| posted on 15/12/14 at 12:43 PM |
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quote:
Originally posted by rdodger
I used MX5 telescopic column, offset steering shaft and Momo MX5 steering wheel with centre cover.
The IVA inspector didn't check or ask about the column.
If this is the car you submitted then I can see that he would be satisfied
[img] [/img]
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rdodger
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| posted on 15/12/14 at 02:48 PM |
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Wow! That's a big picture!
Yes that's the car.
Loads more build pics here if you are interested.
https://www.facebook.com/pages/Thruxton-GT/1414415458799133?ref=aymt_homepage_panel
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CosKev3
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| posted on 15/12/14 at 04:22 PM |
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Standard Sierra wheels pass ok, pretty sure they are not collapsible at all!
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bumpy
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| posted on 15/12/14 at 06:50 PM |
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Now that's interesting as I thought they were.
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