I headed out today with the intent to have a ride of enjoyment, not necessarily a workout. Since my original plan to ride Saguaro National Park East was made impossible by a running event they are having there today, I decided to ride most of the route I planned and called the mini-matterhorn. I figured I don't have low enough gearing yet, but I can ride up to Mt Lemmon Short Road and cut off the mini-matterhorn piece. Yet..., if I was feeling extra good, I might actually try it.
I did try it. RidewithGPS calculated the max gradient of the route at 9% when I planned the route. I thought it was much steeper, but 9% is what Ridewith GPS recorded on the Star Pass TRC route we did Saturday. So that wore in the back of my mind for the 38 minutes I was riding before I got to Mt Lemmon Short Road. It was too tempting. Worst case, I would have to pull the trike up the hill so I went just past Mt Lemmon Short Road and turned onto E. Coronado Rd, the short spur of the mini-matterhorn.
I made it 3/4 of the way up, but my front wheel was being pulled to the left and I ended up zig zagging across the road once, but when I got closer to the top, there was absolutely no visibility and if a car were to come over the top, I would be toast. I had to stop and not zig zag. I don't know if I could have made it had I zig zagged, but it would have been right on the limit if I could have.
I should have taken a picture looking back down the hill at that point, but I didn't until I got the trike to the top. I, therefore, don't have a picture that does the hill justice. Though, I do have pictures of the awesome view.
The ride down the other side was very quick.
Oh, and by the way, the gradient recorded is 15.1%. Much more than the 9% the route planner calculated.
I have a 26t chanring on order to replace my small 30t chainring. That will take my low from 20.4 gear inches (1.63 m development) to 18.6 gear inches (1.48 m development). that is about the same magnitude of change between my current 1st gear and 2nd gear, so I will get another gear. That is about 1/2 gear inch lower than my Tour Easy, but about 1 gear inch higher than Daunell's USX.
You can guarantee I will be back to conquer this hill once I get that lower gear. It will still be a challenge, but I will conquer!

I looked at the profile going backwards (i.e., CCW) and the climbing max gradient is slightly less at just over 14%. So, it is about 1% gradient less steep, but longer climbs of over 9% gradient.