>>1521279>. I only use my 4 largest gears and even then usually just 2 and 3.if I understand you correctly, you don't use the small, low tooth-count cogs in back because they're too difficult to push?
the easiest thing would be to get a smaller chainring, which would make the ratios easier across your whole rear cluster. that way you'd hang out in 3456 and use 1&2 on tough climbs and 7&8 on fast downhills.
for a 130mm bolt circle, I believe 38t is the smallest that will fit, assuming a 5 bolt circle. might be different for a 4 bolt circle. try one and if it's too low go somewhere in the middle. but after a few years when your legs are strong you can switch back.
the bolts just use hex wrenches but the nuts usually have a funny slot in them. I used a butter knife last time I changed them but there's a tool you can buy.
this will put slack in your chain. if the rear derailleur pulleys can't take up the slack enough when attempting to shift to the little cog, you have to take a link(s) out, which requires a chain tool.
if you have a coop nearby, they'll have a bin full of rings, at least one of which may be sized right with decent life left in the teeth. it'll cost nearly nothing and they'll have tools and stands you can use and the staff may be helpful also.
changing cranks or rear cassete requires special tools and it's somewhat more involved than just bolting a new ring on. not too bad, though. but personally I'd tinker with the chainring first. if you get strong enough to want more range in the future you can get a double crank, or whatever number of cog cassette your hub will hold, or both. but it doesn't sound like you're there yet.
