gear calculator

Currently on a 50/34 - 28 - absolutely go anywhere. Comfortable with this! Am looking to change to a 53 / 39 - 32 - simply because I have a good deal on it. Can alternatively swap for the semi 52/ 36 - 32 or 28 Are any of these worth doing and I apologise for being completely useless at Maths...

Can anyone recall when it was possible to the spit and join of their cassette sprockets, thus customise them, brilliantly!