Plunger A10 Gearbox marking

[AdrianJ]

My gearbox is stamped “R” where i would  normally expect to see STD or RRT or some such.
Does anyone have any idea what R indicates please?
Adrian

[berger]

REJECT only kidding, havn't got a clue

[Greybeard]

Reconditioned?

[berger]

I have not been to the pub, and the gender neutral diverse man flu is in dissipation, no casualty visit needed [cheers greybeard] I think REPRODUCTION/  Raillery

[AdrianJ]

Reconditioned?

Sounds plausible. There is no sign of any other mark. No STD.

[WozzA]

    Reverse      

[BritTwit]

I have yet to figure out the stamp code on semi-unit boxes.  Of the four units that I have, one is marked XX ond one is marked MB.  I'll check the others when I get to the shop tomorrow.

[AdrianJ]

That helps thanks. I was worried that I might have a close ratio box as I am fitting a Steib sidecar and hoping to get away without changing the sprockets.
Adrian

[Rex]

"Worried" about having a CR box fitted?

Nicer problems to have!

[AdrianJ]

Rex, A CR box isn’t much use with a sidecar! And I don’t want to have to change it.🙂

[JulianS]

The plunger boxes were not available with the many different internal ratios of the swinging arm box (which mainly came from Gold Star applications)

If you look at the 1950 and 1951/52 parts book posted here in January 2018 you will see the plunger box was listed with either close ratio or wide ratio internal gears, the later being listed an optional which, I think, some riders prefered to go with sidecar sprockets.

https://www.a7a10.net/forum/index.php?topic=12471.0

Move to the 1959/53 book only one set of internal gears offered, the parts now being the same as those previously described as "close"

So plunger "close" is not the same as swinging arm close.

[AdrianJ]

Thanks very much Julian. Very helpful. As everything is almost back together I think I’ll try riding it to see what it’s  like.

[BSA_54A10]

The plunger boxes were not available with the many different internal ratios of the swinging arm box (which mainly came from Gold Star applications)

If you look at the 1950 and 1951/52 parts book posted here in January 2018 you will see the plunger box was listed with either close ratio or wide ratio internal gears, the later being listed an optional which, I think, some riders prefered to go with sidecar sprockets.

https://www.a7a10.net/forum/index.php?topic=12471.0

Move to the 1959/53 book only one set of internal gears offered, the parts now being the same as those previously described as "close"

So plunger "close" is not the same as swinging arm close.

Always looking for some one to confirm this theory but to me it appears that the plunger boxes were a bought in item as next to nothing on them interchanges with the rigid or swing arm boxes where as the latter share most of their internals with all other pre-unit boxes right back to the original 1910 500.