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The highs and lows of technical debate
Page 28
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AS THE AUTHOR of the piece on the AEC Mammoth Major MkI I I in which I am accused by Robin Hannay of "making a common mistake" by describing the 6.25:1 axle ratio as"high" and the 7.1 as"low"( CM 30 June ), it is Mr Hannay who has his facts wrong and not I.
What he says goes against the universally accepted principle that a high-ratio axle (numerically low) provides greater road speed,while a low-ratio axle (numerically high) gives better gradeability.
Having spent many years writing technical data on trucks and liaising with engineers on the subject of drivelines I would not make such a mistake, If Mr Hannay's claim is true, how would he explain that you select "low ratio" on a twospeed axle when climbing a hill, and return to"hig,h ratio" for normal high-speed running?
Did Eaton Axles get it wrong too? Look at the table that appeared in CM,16 December 1949, (pictured above) in an article discussing two-speed axles. Need I say more?
Peter Davies Flitwick, Bedfordshire