I have a 28 teeth sprocket and need to know what size to equal it out with free wheel?

Question

I Have A Redline BMX And I Need TO Equal Out My New Sprocket So I Dont Pedal So Fast, But I Dont Have Any Tools But A Chainer Breaker, Master Link, And The Basic Vise Grips And ScrewDirvers Ect. I Also Need To Now How Many Teeth (12-18) And Last Of All Do I Just Need A http://www.danscomp.com/461054.php?cat=PARTS

Answer 1

actually you should run a 10t in the back 9ts would be better with a 25t chainwheel heres a good chart that should help you out  http://www.danscomp.com/serve.php?serve=...

Answer 2

The short answer would be a 9 tooth cassette (for a standard setup) however it's all a matter of taste really and you'll need to do a little math to work it out. Here we go:

Divide the number of teeth on the front cog (chainring) by the number of teeth on the back cog (freewheel or cassette) and see what you get.

eg 33T on the front 12T on the back equals 2.75

If you take 2.75 as the "average" value as a lot of stock bikes have this. It basically means that it's not too hard to pedal and you get a reasonable top speed.

Flatlanders like to pedal very easily and don't need a high top speed so they would reduce the number of teeth on the front cog whilst keeping the back cog the same (eg 23T front 10T back). Then if you do your sums you will have a value of less than 2.75.

If you're doing jumps and carving then you may just need a little pedal to get going then your momentum will do the rest (gear ratio less than 2.75), or you may like to get even more speed after a push off down a ramp with extra pedaling (gear ratio more than 2.75 but not more than 3.2 as you'll really struggle higher than that)

I personally like to go fast and currently have 36T on the front and 12T on the back equaling a value of 3. To save weight I'm changing my cogs down to 30T and 10T, I'll have smaller cogs but the sums still make 3 so my bike will have the same acceleration and top speed. A sum of 3 is a less popular but although I found it difficult to pedal at first, my legs were used to it in a week and now anything lower that 3 (I have a 2.75 bike too) doesn't feel fast enough!

See if you can go down a BMX shop (with a calculator) and have a test ride on some different gearing setups.

Sorry for the long post but I remember the stress I had trying to work out gearing for the first time! It also seems you're not alone as I've copy paste and modified my gearing post quite a few times.

I hope this helps you but if you're unsure before you change anything just go to a probike shop that sells good BMX parts.

Good Luck

Answer 3

i would agree with the previous poster. try the ten tooth, any bigger and you wont be going anywhere.

when dealing with such small sprockets one tooth in the back makes a huge difference.

28 - 10 = 56 (which is as about average)

28 - 9 = 62.2 (which would be pretty tough to pedal and especially out of gates)