**I take my twins to preschool by car, and I'd like to switch to doing it by bike.** 

There's a hill, and we're heavy, and I'm not in great shape, so it's hard. I've done it a few times, but I always collapse when I get home, and I certainly don't have the energy to do it twice (drop-off + pick-up). I take a while to recover. It takes a lot longer, too.

I also would like to always bike to the grocery store and other errands, but they are within the range of the preschool, so let's focus on that one for now.

I'm looking at **electric-assist bikes** as a way to overcome the hurdle and starting doing this trip by bike (almost) every time. I've seen bolt-on hub-motor systems for as little as $300, and Big Dummy + Stoke Monkey setups for $3000+. 

**Data:**

The bike + trailer + me + passengers weigh **430 lbs**. There's a 230' climb on the way there, and 110' climb on the way back. I can drive it in **4 minutes** but biking takes **20 minutes**. 

**How much motor (and how much battery) do I need to invest in?**