Shopping for a light weight ebike to replace my Aventon cargo bike. I want the flexibility of easily loading the bike into my Suburban and taking it with me, and the Aventon (while a great bike), is just too heavy.

Specialized Creo or Vado SL is a great bike. Maybe let us know what kind of riding you are doing and what you are looking for and we can provide better suggestions.

You didn't mention price and, while not a big fan of them, folding seems optimal for carrying in a Suburban. The Lectric XP2 Lite @ $799 (maybe less with Earth Day coming) would be my choice.

Folding ebikes that are light weight, and that I currently own, are the Lectric XP Lite (single speed w/rear hub motor and gates carbon blet drive) and the Dahon Unio E20 (mid-drive, great ride quality, torque sensor). Dahon also has the K-One (rear hub motor w/gearing) and the K-Feather (smaller 16" wheels, single speed). I also have the Fiido L3, but that's more of an seated electric scooter, since pedaling it is useless. It's fun to cruise around on and take in the scenery or use for commuting (since it's small and gets about 50 miles per charge - they're claiming 124 miles per charge). It's around 50lbs though, so it's a little heavy, but doable.

Santa Cruz Skitch is a lightweight E-Bike

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In addition to the price, Larryo should also define "lightweight" better.
"Lightweight" for an eBike in general is anything under about 55 lbs. Typical is 65 lbs, and they go up to 90-ish.
"Lightweight" in general bicycle terms might be under 25 lbs.

Also, how are you putting it in your Suburban? Do you have the back seats down, so it's a giant SUV, or are you trying to get something in with just the 3rd row down, or ?

I have a Lectric XP Lite, it was sold as 46 lbs. I added a folding lock, rack & fenders, so it's probably closer to 50. I wouldn't call it lightweight. Maybe 15 lbs. less than your Aventon?

I also have a Tern Vektron, which weighs about 50 lbs, which is "light for an eBike".

Aventon's Soltera is closer to 40 lbs., IIRC.

In the meantime, you might consider just buying a 2x12 to use as a ramp to roll the Aventon up into the Suburban.

Never been inside a Suburban, but:
My 29pound Orbea Gain fits into a Chrysler mini-van with the 3rd row down. it is an XL size and I do not have to lower the saddle or remove front wheel (which extends forward a bit between the 2nd set of seats.

Look at Urtopia - lightweight carbon fiber bikes