I met a gentleman at Interbike this year who was interested in our bike seat more for the load-bearing capacity than the ability to provide an extra seat for a passenger. He stored the batteries for his ebike in a Topeak bag on an MTX bike rack; the problem was the weight of the batteries would bend the rack after only two or three rides, so he was going through bike racks almost once per month! I knew that our bike seat frame was more than strong enough to support the load of the batteries, but I needed to make some modifications to make it work for him as a cargo rack.
First, I needed to remove the seat cushion and the stash-box from the top of the bike seat frame. Once those were removed, I used a rivet tool to affix the lock directly to the frame (since it feeds through the stash-box for our bike seats).
Next steps were to figure out a way to securely mount his existing Topeak bag to the top of the bike seat frame (aka. Companion Cargo Rack). I decided to make a custom base-plate for the bag that would fasten to the cargo rack, locking in place using the existing lock. After putting together some design sketches, I picked up some supplies at the local hardware store and voila! I had a base plate that locked in place using the existing lock, and was more than strong enough to carry the load of the frame.
He ultimately ordered four Companion Cargo Racks and wanted a second cargo back base plate made since he has two ebikes that were both having the same problems with the Topeak racks. So I made the modifications to a couple more bike seats and his cargo racks were just about ready. The final step - installing the rack onto his ebike.
I had to come up with a modified seat-post mount, since his seat had two seat posts rather than one. But taking advantage of most of the existing components, I was able to come up with a solution that worked great!
All in all it was a really fun project. I got to take apart our bike seats and become intimately familiar with the assembly of the bike seats (which I probably should have done years ago).
And the best part is, we have the makings of a new product line for Companion Bike Seats now: the Companion Cargo Rack! Being that our frames were load-tested at over 4,000 lbs, this is the beefiest bike rack on the market! Stay tuned for more on when we release our new cargo racks!