I'm assuming you're talking about a BMX here, which use the words a bit different from the rest of the cycling world.
So it's the size/tooth count of the freewheel that you're asking about.
And then it's just as much about what you want as what you need.
When you change the sprocket/freewheel size you change the gear ratio.
A big sprocket and a small freewheel lets you go fast, but you'll have to push harder.
A bigger freewheel will cost you some top speed, but will make it easier to get the bike moving.
A very common combo is 25t front and a 9t rear.
if you mean your gonna have a 25t chain wheel and a 13t rear sprocket then go for it, I'm about to do it.
25t means that there is 25 of the little spikey teeth on the outside of the sprocket :]
yes it has a 26t sprocket
The chain length needed is determined by chainring size, sprocket size and the design of your frame. There's no way of saying that you'll need from the sprocket alone. On top of that there isn't much to choose from when it comes to half links. They are all of the same length and in width there are two options 1/8" or 3/32". You need one the same width of your chain.
if you are looking for a 25t sprocket then you need a 9t rear driver other wise it going to feel like you a pedaling forever and not going anywhere there are websites or just look online for proper bmx gearing ratio's also you may need spacers for your cranks
well if you have a 8 tooth rear driver you will need a 23t sprocket, if u have a 9 tooth rear driver you will need a 25t sprocket, if u have a 10 tooth rear driver you will need a 28t sprocket, and if you have a 11 tooth rear driver you will need a 30t sprocket
If the driver/freewheel isn't too badly worn you can keep using it even if you replace the sprocket.
Yes, and 3 piece cranks.
Yes Pretty much all 3 piece cranks should fit any sprocket you buy for them.
That's like asking if a size 10 shoe is better than a size 11. You need one that fits, that's all, what size it is isn't that important. I'm assuming here that you are talking about a BMX, and the sprocket by the pedals, and that you're planning to keep the "driver"/rear sprocket. If you feel that you're too slow off the start, then going from 32T to 25T will make you quicker to get going. The downside is that with the 25T you will lose a bit of top speed on account of not being able to spin the pedals any faster. If you think you'rfe doing OK from standstill, then replacing the sprocket will make you slower w/o anything good to trade for it.
The chain length needed is determined by chainring size, sprocket size and the design of your frame. There's no way of saying that you'll need from the sprocket alone. Chains are pretty much always bought a tad too long and then cut to length during asssembly on bike.There isn't much to choose from when it comes to chain width for single-speeds, they're either 1/8" or 3/32" with 1/8" being the most common.
25T 9T rear driver ive got one orders for x-max its coming in about 70 days :|
i wouldn't say its big but a 22sprocket is the smallest you can get from gtrider