Can you Change from 7 Speed to 9 Speed?

Question : Hi if a had a 7 speed cassette and I want to change to a 9 speed cassette do I have to change the freewheel.

Hi Matthew,

There are many reasons why you can't change to a 9 speed from a 7 speed. The freehub body is different and if you where to try to fit a 9 speed one on the existing hub it wont fit and will be too long for the axle and possibly too wide for the rear of the frame. The best answer is to buy a new hub and have the wheel re-built or buy a new set of wheels.

If you were to change the rear wheel for a 9 speed then you could be having more problems with you gear levers as they will be 7 speed and so will the rear mechanism. All rear derailleurs are similar, but you will find that an older 7 or 8 speed will not work well on 9 or 10 speed cassettes. If you are using old friction gear levers on the down tube then there is no problem with the gear change as you can fine tune the gear change as you ride, but with any index system, be it on the down tube or a brake/gear lever then these will have to be changed also, as they will not work. There will not be enough clicks on your indexing.

You need to think about this, if you start to change one thing on the gear system then you have to change everything and if you have an old bike then you might be better to buy a completely new bike as this is a cheaper way to get a modern gear set up. Just like computers, bikes are changing, not as fast as electronics, but they become out of date very quickly. It's not an easy thing to do and can turn into an expensive up-grade, sorry Matthew, but it's not an easy one.