Hi all,  I'm hoping you can help. I just bought the Rad Expand 5 and the Serfas Super Cruiser seat to replace the stock seat. However, the distance of the rails on the Serfas seat are significantly (4-5mm) wider than the stock seat and the bracket from the Rad Expand seat post doesn't fit. It seems like too great a distance to try to squeeze the rails together to fit the Rad seat post and clamp; it seems like it could pop out of the bracket if too much stress is put on it while riding.

I'm new to e-bikes and I can't figure out if there's some sort of adapter I need to buy. Or, should I give up on the Serfas seat and try to find a seat that has the same rail width as the stock seat? I've attached two pics: one showing how the stock seat bracket is too small for the Serfas, and the other is a pic of the bracket that came with the Serfas, which doesn't at all fit the Rad seat post. I've seen online that others have used the Serfas  seat for their Rad bikes, but never mentioned the rail issue. Advice greatly appreciated! Thanks.  Eleni