Bike Chain wheels

Question

if i get a bike and want to replace the chain wheel

do i have to get the same amount of teeth on it

lets say i get a bike and it has 25 teeth

can i get one with 22

or do i need to get a new chain if i want a smaller one

Answer 1

You can change sizes if you want to, but you have to take a few things into account.  If you want to drop to a 22T chainwheel, first make sure that it won't give you any clearance issues with the chainstays or the brakes (not just the chainwheel itself, but the new lower position of the chain).   Also, by dropping down 3 teeth, you're going to have a lower gear.  If you don't like that, then you'll also need to drop your freewheel down a tooth or two.....that might mean changing to a cassette driver (which means either a new hub or a new rear wheel).

You can take out a link or two of chain if you need to, or you might just be able to adjust your tensioners for the slack.  If the old chain has been ridden much, have a shop measure it for wear or just replace it with a new one.  That way you won't prematurely wear out the new chainwheel and will be less likely to have skipping or derailling problems with the new gears.  

Hope this helps.   :o)