Hi there. I currently have a Decathlon's B'twin 7 (http://www.decathlon.co.uk/btwin-7-id_8076847.html). Chainrings are 48-38-28 and 7-speed cassette 14-28. I'm going to pull a heavily-fully-loaded BOB trailer for a couple of months, mostly on flat roads, but 20% in mountains.
I've been training but it turns out that pulling it on steep uphill with no sort of granny gear will not only force me to stop every 500m, but eventually injury me on the long run. So i'll consider changes, and as i'm totally newbie i'm asking for your help.
1 - Taking a look a Sheldon Browns gearing calculator, i could change the smaller chainring from 28 to 20. The lower gear would no longer be 28gi, to become 20gi... i think that would be enough for no-hurry-touring?!
Does it make sense? Would this be feasible? (I mean, compatibilities and other stuff i may be totally unaware)
2 - With the loaded bike i'll never use the higher gears. I know it would be wiser to upgrade the crankset, but wouldn't that be more expensive?
3 - Help me!
(Also, you're free to comment whether the bike is inappropriate for touring. It's just i'm on a budget and i'll rather spend it on the road, even if i go slower...).
Thanks in advance.