Modern Vespa

Will likely be picking up a modern small frame Vespa soon, and am anticipating my helmet not fitting under the seat (medium Shoei RF1200). Won't know for sure until I get the scoot (unless someone here has already tried fitting an RF1200 under the seat), but I'm looking at top boxes for some of my riding gear at the very least. If I have to accommodate a helmet I'll need one of the bigger options. I'm not too worried about form, and am considering either the Givi E43 or Shad SH40. How big is too big when it comes to a top box?

They're both pretty big boxes. I had a Shad 47 on my last scooter that fit two helmets and more importantly two large bags of shopping. Now I have the Medley with a lot more under seat storage, I went with a 37 litre Givi. The big box was great but made tight filtering a little bit harder. I would go as small as possible that still suits your needs.

If you pop the seat, there's a peg that you can clip your helmet to and then close the seat. This allows your helmet to be stored outside the Vespa, but in a secure way - but no good if it rains.

There are apparently some full size helmets that will fit under the seat, so this is also another option if you don't want a top box.

In terms of top box size: are you allowed to filter between cars in your location? And are you in a windy location?

I have the Givi E300N2 size on my three scooters and have had to do work on friends' scooters because they had larger top cases.

I strongly recommend against going much larger than 30L. That size will hold a modular helmet and sufficient miscellaneous gloves and other small bits. If you go larger than that, the wider case even if left empty when riding can impart a lot of leverage on the mounting bracket and cause a lot of undesirable, unintended consequences like broken fasteners, mounting plates, and brackets.

Agree that the smaller the top box the better, so I'm hoping my helmet will fit under the seat. If not, I think I can get away with the Givi B32N instead. Watched some YT reviews and unboxings for it and the cube profile really lends itself to more usable interior space. I'm going to measure the volume of my helmet and miscellaneous gear and see if I can somehow make it fit within the interior dimensions I found.

To answer JakeM's questions: I'm in California, so yes I can filter/lane split. And yes it can get windy in the Bay Area. I often have to shelter or take off the cover from my current scooter so it won't get blown over (which happened not too long ago ).

Thanks everyone for your feedback!