I have ridden every gear combination possible, from 48 gear inches to 82 gear inches.
Seventy-two gear inches seems the highest I can ride without skidding (I don't believe in skidding because it takes longer to stop and it wears out good tires).
I have read some good arguments for 63 gear inches as the best all-around gear ratio.
I presently ride at 60 gear inches and I get around town as fast as I ever did at higher gear inches, but I have more fun, feel safer, and have waaay more control over the bike and myself.
I have found that most hills will yield to proper pedalling technique and bike fit.
As for fit, when out of the saddle, your bike fits right if you can visualize your knees headed towards your hands; and, if your knees seem headed towards a point either above or below your knees, then you need to adust your out-of-saddle hand position.
As for pedaling technique, you should pull yourself uphill rather than mash yourself uphill.
When you get out of the saddle, lean forward and pull the pedal up by directing your knee towards your hand.
If you mentally focus on pulling your knee towards your hand, it will correctly energize the very large thigh muscles that run from your pelvis to your lower leg bones (and which never touch your thigh bone), and the use of these muscles in pulling will cut the amount of strength and energy required in half.
If you pull correctly, you will not feel yourself mashing, but you mash nonetheless.
If you feel yourself mashing, you need to pull more.
The above requires clipless pedals.
If you ride with clips and straps, you will never climb as easily as someone who rides clipless.
Also in regards to climbing, riding at a lower gear ratio will improve your spin dramatically, making it much more efficient, to the point where you will go up hills in the saddle that you formerly had to get out of the saddle in order to get up the same hill.
When you spin, first imagine your spin as a square, with an up, down, back and forward component.
After you can see the square, change it to a teardrop, with the pointy part of the teardrop in the back bottom portion of the former square.
This imagery will require you to, and will help you to
DROP YOUR HEEL into the back point of the teardrop, or the bottom rear of the square.
Dropping your heel will help you "scrape" on the bottom, and it will set you up for "pushing" over the top of your spin.
Also, riding at lower gear inches will help you improve your spin.
If you try to remind yourself to visualize your spin, or concentrate on your spin, you will find that after about two years of riding you will easily go up some hills in the saddle that formerly required you to get out of the saddle.
You'll still need to get out of the saddle for the very steepest hills, but you'll get up them easily with just a little puffing at the top of the hill.
To understand gear inches, go to the following site and play with the numbers:
http://software.bareknucklebrigade.c...it.applet.html
The person who designed the applet, above, deserves some sort of award.
Please write to him and thank him.
When you go to the above site, please note that 60 gear inches allows you to cruise at 15mph at 84rpm.
A four minute mile, easily, uphill and downhill, with and against the wind.