At the outset, it is necessary to consider whether the operation of increasing the number of adjusting gears on a bicycle makes any sense at all. Perhaps it results only from the desire to bury the bicycle in front of colleagues. If so – I suggest to invest in a better shock absorber, brakes or SPD pedals – you will have more use for it:]
Increasing the number of gears on your bike will not make you drive faster. The range of gears can be exactly the same on a 7-row and 9-row cassette. For example, 11 teeth on the smallest sprocket and 32 on the largest. The difference will be only that it will be easier for you to choose the right ratio to your current needs. In recreational driving, it does not really matter. I used to ride bikes with seven gears and nine and when I traveled to tourists, or quite a selection of these seven gears in the city (and in fact the four most-chosen) quite enough. Learn more – How to buy a bike online – everything you need to know?
In addition, such an exchange is not financially viable. Why do I think so? Increasing the number of gears in the bike involves exchanging at least: the chain, the cassette, and the right-hand grip. If you have a freewheel, not a cassette – you will have to replace the rear hub, which involves either buying a new wheel or interweaving the old one.
Changing, for example, the drive from 8-to 9-row, we must, therefore, count at least 50 PLN for the chain, 60 PLN for the cassette and 60 PLN for the handle, which will total 170 PLN. If we order the replacement of these parts on the site, the sum will increase to about PLN 200.
Additional costs will meet us when we have a freewheel in the bike. The hub adapted to the cassette is 50 PLN + interweaving the wheel depending on the site is 30-50 PLN. The cost of increasing the number of runs in the bike will increase to 300 PLN. The prices which I gave, of course, are indicative and concern brand (Shimano) but cheaper elements. If you want to buy items from a group such as Deore – we will spend more.
Replacing these parts only makes sense if the chain and cassette are still fit for replacement (because they have worn out). Then an additional (minimum) 60 zlotys on the handle will not be such a bad choice anymore. Otherwise, I would just wait until we bought a new bike and then I would look for one with nine or ten rows.