does anyone sell an inner tube as above, with the correct offset valve for lambretta rims, but with a 90 degree angle, to fit on the rear without the hub being in the way ? I think the one in there was from Sandy Scooters, but sadly that's not an option

, and i want to change my rear tyre, and like to change the tube at the same time.
or do the Mypol ones have sufficiently short valve stem to clear the hub ?
I've only ever fitted them to the front before.
thanks