I have a Trek FX and I wanted to change the gearing from 48/38/28 to 48/36/26 and I was wondering if that's a job where I would need any special tools. Also if I do get into this can I use the BB on the Trek or should I get another BB to go with the Sugino. If I get a new BB what size would I need? I noticed on the Trek a crank with an allen head, and on the picture of the Sugino I see a square hole on the crank. I was also wondering how much I would gain by all this? As you can see I know nothing about bikes,but I'm trying to learn and I'd like to tackle this.With the crank I take off the Trek I was thinking I would put it on a 1979 Schwinn,if it fits.Any answers will be appreciated,thanks George