About three months ago I bought a second hand bike for £70; to be honest it is reasonably good. Current setup for gears is a 2 x 18 (38-48 front, 13-28 rear).
As far as I can tell it's not a branded Shimano system, just some generic Shimano 8 speed (the shifters say ST-2200 and the RD looks like the RD-2200).
I want to upgrade the bike as I keep having to re-index the RD, and I think it's just worn and sluggish. Also I want a cassette with a larger low gear (maybe a 30) as I have a big hill by my house and I struggle to get up it.
I was thinking as Wiggle has a sale I would upgrade to Shimano CS-HG41 8-Speed Cassette 11-30T and Shimano Sora R3000 9 Speed Rear Mech. I was thinking of possibly changing the 38 chainring to a 36 or even a 34.
I ride 8miles to work and back 4 times a week (64miles a week) with a backpack for food and clothes, and as I said the bike isn't too bad, I just want the hills to be a bit easier.
Would the above new setup be ok, or is there a better way of me achieving this?
I have added a link to a bike calculator for my hopeful setup.
Thanks for any responses.
I had a look and the smallest cog does have another set of holes about 65mm in diamater. Also the holes on the current smalles chainring are 125mm.