Best Way to Upgrade My Bike 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.

http://www.gear-calculator.com/?GR=DERS&amp;KB=38,48&amp;RZ=13,14,16,19,20,22,24,28&amp;UF=2150&amp;TF=80&amp;SL=2.5&amp;UN=MPH&amp;DV=teeth&amp;GR2=DERS&amp;KB2=36,48&amp;RZ2=11,13,15,17,20,23,26,30&amp;UF2=2150

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.
2200 is the Shimano Claris line from 2009, so not 'unbranded', but at the bottom end of Shimano hierarchy.

Firstly, the derailleur itself is probably not causing shifting issues. Replacing the shift housing and cable will very likely fix the shifting and keep the indexing properly adjusted. Check chain and cassette wear as well.

A 9 speed Sora derailleur with a 8 speed cassette and Claris 8 speed shifter should in fact work. The reason is that all Shimano road rear derailleurs and shifters at 10 speed and below generally use the same cable pull ratios. You can also consider the Claris RD-R2000, which will work a little better than the RD-2200. 

The RD-R3000 and RD-R2000 will work with a cassette with a large sprocket up to 34 teeth.

The 48/38 crankset is a bit weird. Fitting a smaller ring depends on the bolt circle diameter (BCD) of the crank. What has probably happened is that a previous owner has fitted a smaller big ring to a 130mm BCD crank which limits the small ring size to (usually) 39 teeth. If the BCD is 110mm, you'll be able to go to a 34 tooth small ring at least.

Remember that if you do change the cassette you'll need to replace the chain as well.

Edited to add: There is another route to a drivetrain with a spread of ratios - buy a different used bike that has what you want (and re-sell the current bike). This is my standard advice in these situations as upgrades can easily cost a significant fraction of the original cost of the bike, and entail headaches and frustration.