Here’s a reply to your post I took umbrage at. Your post is in italics: my replies are not.
The Rockwell hub pattern would match the ERF example which you posted earlier ?.
It might, yes.
We also seem to have a connection between that of the orange unit and the military examples ?.
Only the lighter weight ones.
The most surprising part seems to be that the Scammell heavy bogie is shown as being higher weight capacity than whatever the 65t artic spec uses.
Unless the shown figures are at cross purposes regarding weight bearing strength, as opposed to tractive effort torque capacity.
The latter would obviously be all about the relative difference between GCW v GTW design capacities.
Perhaps there is a cut-off point after about 150t gross where a ballasted tractor is more viable. I have no idea. An STGO driver on here might know. I’ve just looked in my old CPC (Operators) books and can’t find anything in there.
The seemingly larger looking hub reduction shown on the orange unit and the military artic, possibly pointing to maybe a larger weight bearing capacity, but a lesser torque and tractive effort capacity v the Scammell heavy ballast tractor orientated design spec ?.
We’re guessing.
That’s why it’s so important to differentiate GCW artic applications, which not only have to provide sufficient tractive effort, but also bear the load of a semi trailer, v GTW ballast tractor applications requiring possibly relatively less ballast weight bearing capacity but more torque tractive effort capacity in the diff and half shaft components.
The orange unit and military artic options shown ( SOMA ? ) possibly using seemingly more hub reduction, to meet their tractive effort requirement, than the Scammell bogie required, but the heavy 300tonner Scammell bogie possibly had/needed relatively less ultimate weight bearing capacity it’s job being to pull loads, not bear the weight of them ?.
Kirkstall also made hub-reduction axles like the D85 (13t) example.
