Originally Posted by
tjakins
Thanks for all the encouraging replies. I'm not sure how to answer this question - I'm not sure of the year, but I'm assuming it's a 2008 Trek 7.3 FX. It could be a 2007, but from what I can tell, it looks like they have the same gearing. I don't know anything about gearing, so any help would be appreciated.
Ok so the 7.3 has a small chainring of 28, and a big cassette cog of 32. With 700C wheels, that gives:
Low ratio: 0.875
Low Gear Inches: 23.0
Which means that for every time you spin the pedals, the wheel spins 0.875 times.
Not "optimal" for gigantic climbs; many people recommend going down to 18-19 gear inches for loaded touring; since we're clydes I'd say that our weight makes us similar to "loaded" tourists
. But 23 gear inches is hardly a bad gear to climb in either; my lowest right now is 27.6 GI (though I will be lowering it soon to 21.4 to tackle hills, very close to your lowest gear).
I notice you didn't specify which gear you were attempting to tackle the hill in, and normally I wouldn't ask this question for fear of offending the rider... but since you seem unfamiliar with your bikes gearing... were you in your lowest gear on the hill? If not you should definitely downshift as low as you need to go.
If you *were* in your lowest gear, then there may be a mechanical solution, but it's not going to be cheap. Your cassette is pretty good; 32 is a great low gear in the rear. I think the only thing that's commonly available that is lower is 34, which won't offer you much of an improvement on how low it can go. If you swap out your cassette for one that has a 34 low gear (Probably $40 or so), you go down about 6% in gearing, which will hardly be noticable, from 23 GI to 21.7 GI.
You may need to swap out your chainrings (looks like you have 28/38/48), which could be more work and a lot more money depending on what kind of crank you have. Since Trek changes specs every year, I can't say for sure whether the 7.3 FX in 2007 had welded chainrings or removable chainrings. If they're welded, you may have to replace the entire crankset and go with a 22/32/44 rather than a 28/38/48. This will be expensive.
If they're not welded, however, you may be able to replace your smallest chainring with a 22, and keep 22/38/48, which gives you a new low gear of 22/34, which is about 27% lower than 28/34. I don't know how well this might work, because it's a large jump from 22 to 38, so you may need to have a bike shop look at it and see what works.
If you don't want to spend money, then it may be time to try out the flatter routes and ramp up to the hills, though.