Update. Yepp bike seat fits but it's a bit of a squeeze to get on.

Here's what I did with mine.

Front rack + $12 milk crate from Home Depot. Requires washers with 4xM5 screws about 20-25mm in length I believe.

Thanks so much MSNDAVE for the info.

I did check the tire width for both and it seems like the EXPAND 5 has a 1 inch increase compared to the step through.

Also, on the website it says it's not compatible:
Compatibility
All 2018 and after model ebikes except RadMission 1, RadMini (all model years), RadMini Step-Thru (all model years),and RadExpand 5

But the video you showed the guy was able to squeeze it on. Do both bikes have the exact same rack?

Hi community (reposting because this thread seems to get more viewers),

I am interested in using the Rad Expand 5 to transport my toddler to and from day care.

I am aware of some of the limiting options we have for the Rad Expand 5 and I am having a hard time finding a child seat that is compatible with the rear rack. Does anyone have any suggestions or ideas? I am not interested in getting a trailer either.

Thanks!

Hi community,

I am interested in using the Rad Expand 5 to transport my toddler to and from day care.

I am aware of some of the limiting options we have but I am having a hard time finding a child seat that is compatible with the rear rack. Does anyone have any suggestions or ideas? I am not interested in getting a trailer either.

Thanks!