Lifting ban on hold
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• Planned changes to Construction and Use rules which ban the use of lifting tag axles from January and their manufacture after 1993 have been put on hold. The changes concerned the redefinition of overhang.
When altering national regulations the Department of Transport is obliged to notify the EC's committee for the standardisation of technical regulations. But the committee has decided that the different national requirements relating to retractable axles need to be harmonised and pending the outcome of the EC draft (due within nine months) the DTp still expects to be able to address its main concern for limiting overhang.
No concession is envisaged for tractive units other than where an axle, placed either in front or behind the drive axle, can be raised for a limited period to improve traction.
Scania makes the most prolific use of lifting tag axles on tractive units in the UK. It claims this reduces tyre wear, noise and fuel consumption in the raised position when running unladen.
When laden a lifting axle improves slow speed manoeuvrability and gives an improvement in traction over difficult conditions.
In controlling overhang, legislation appears to favour lifting axles placed in front of the drive axles.
This alternative can be argued to give a better weight distribution between the remaining axles so maintaining better steering control, especially where negotiating an up hill gradient where the lifting device is most likely to be used.