Riese & Müller Packster70 - vibrations

[Tim_]

Hi everyone,
Hope nobody minds if I write in English as I don't speak German.
I have a Riese & Müller Packster 70 since December 2022 (4,700km in total so far) and recently, I've been experiencing very strong vibrations when I'm going fast (>45km/h).
It's systematic, i.e. every time I go at this pace, the cargobike starts vibrating and the vibrations are quite impressive & scary (I feel them in the handlebars). Children in the cargo also feel them.
It never vibrates when I'm going slower than 45km/h.
I was wondering if anyone had any idea what could be the reason. The bike is recent & well cared of, it's overall in excellent shape.
I live quite far from big cities and only have one bike specialist, who has no clue about the reason behind this issue.
Many thanks for your help.
Tim

 

[tille]

Hi,
if the bike is well maintained I suppose there is no slack in the headsets, steering and rear suspension joints if applicable? On a cargobike if this happens I would mostly look at the steering. We've had shimmy on delivery bikes with both too slack and too tight steering cables

 

[Jaap]

The older models of the packster 70 had been recalled 2021 due to similar problems with natural frequency.

Dringender Sicherheitshinweis: Rückruf und sofortiger Fahrstopp für Riese & Müller Cargo-Bike-Modell Packster 70

Riese & Müller ruft mit sofortiger Wirkung das Cargo-Bike-Modell Packster 70 in den Produktionsstandort nach Mühltal zurück. Betroffen sind alle Modelle, die seit Auslieferungsbeginn und bis einschließlich 06. Oktober 2021 ausgeliefert worden sind. Gleichzeitig wird mit sofortiger Wirkung die...

www.produktwarnung.eu

The packster uses a cane creek viscoset to reduce the vibrations.
It's possible to adjust the viscoset for more or less damping.

https://canecreek.com/wp-content/uploads/2018/04/ViscoSet-Shim-Orientation-Change.pdf