The rollers are a feature on Rickerts from a certain era, i remember to have read about them but can't find the source atm.
Ted Ernst once wrote a pice on Rickert on (i believe) the CR list. Excerpt:
„Rickert first used a standard round plate that said Rickert Dortmund on it, until he hit upon RIC.
It was short lived, as there was a German children’s scooter company, that nice one with the 12×2-1/4 air tires which just happened to be called Ric.
The scooter company notified Rickert to cease and desist or face a law suit. That’s when he changed to Rickert and used that until his retirement […] He only used Ric for maybe 1-1/2 years or so […]„
Rickert started his business in 1951 and continued to build frames until 2002. He passed away 2011, aged 83.
His wife Doris was in charge of applying decals and hand lining. These twin lines on the rear seatstay cluster are a bit of a trademark
Heres a nice specimen from the late 50ies/early 60ies with Altenburger gear:
