Almost immediately I realized I wanted more range and although it took me twoattempts, I installed a triple crankset (48T/38T/28T). This decreased the low end of my gearing to 21.5 gear inches. This was a big improvement and made a big difference, both when pulling a trailer on "regular" hills and when riding solo up very large hills. It was a big improvement, but it wasn't enough.
After the Bloomin' Metric Century and the problem I had on that large hill, I started thinking about what I wanted to do. After asking on the 'Bent Riders Online forum and deciding that it was at least worth trying, I ordered a 22T cog. This is equivalent to just below 17 gear inches (or a reduction of a third over the original crankset in terms of number of teeth or gear inches).
Today, I pulled the crankset, removed the old cog and put on the new one.
Crankset with the original 28T granny gear.
Crankset with the new 22T granny gear with the original gear to the right. The new gear really does look a loot smaller, doesn't it.
My bike being held on the bike stand after reattaching the crank.
After taking it for a short test drive, I realized I needed to shorten the chain. The reason is that the diameter of the 22T cog is significantly smaller than the 28T cog and that the chain was too long to be in the small front cog and the higher (meaning smaller in number of teeth and therefore also diameter) gears.
I ended up removing a couple more links than I meant to because the first time I pushed the pin out of the chain, I pushed it completely out and wasn't able to get it back in. After reading online, I realized my mistake and made sure to leave the pin in the second time. I had to break the chain one more time (again, I was smart and careful enough to leave the pin in) because I hadn't routed the chain correctly through the rear derailleur.
Here I'm using the chain-breaking tool. I recommend removing the wheel before trying this.
The second time I was smart enough to leave the pin in and not push it completely out. The white bag is being held by my daughter so the camera phone would focus on the pin and not the floor.
With the new setup, I can still (barely) make it into the large cog on the crankset and the largest (lowest) cog on the rear cassette. You're not supposed to use this gear and I tried to avoid it before, but I'll try harder now. I can be in the granny gear on the crankset and easily make it to the 5th gear on the cassette. I can make it into the 6th gear, but it isn't entirely happy.
Since I had installed a new granny gear, I needed hills on which to try it out. After putting the kids to bed, I took the bike out for an 11 mile ride that went up Flax Hill road (one of the worst hills around here) twice. I averaged 14 mph, which is my fastest ride (over 10 miles) ever. Not bad considering I did Flax Hill twice.
I like the lower granny gear, but the difference between the medium cog on the crankset (38T) and this gear (22T) is quite noticeable. When changing from the second cog to the granny, I also need to move the rear derailleur from the 1st (biggest) gear to 4th or 5th gear if I don't want to spin out (meaning spinning but not turning the wheel because it's moving too quickly). I had similar problems when shifting out of the granny gear and if I didn't change from a high rear gear (say, 5th) in the granny gear to a much lower rear gear for the middle cog on the crankset, I found that it was too hard to peddle.
The first time I went of Flax Hill road, I did use the smallest gear on the bike, but found that I didn't really need to (the GPS claims my speed was as low as 3.6 mph here). The second time I went up the hill, I found the lowest gear quite comfortable although for that particular hill, I would have been quite o.k. in the next highest gear. Here the GPS doesn't report as low a speed, it does show me averaging 4.5 MPH for most of the last part of the hill,
For now, I think I'll go up a size to the 24T ring as the granny gear on the crankset. In the future, I'll consider replacing the middle 38T chanring with something smaller (say, a 34T). Definitely learned a lot playing with this. More tweaking coming soon.