I'm still very new to the concept of gear inches, and I'm needing some help figuring out how this stuff works.
I'd like to give you folks a rundown of my math and methods, and then I've got a couple of questions for the group.
My bike has three front rings, 28, 38, and 48 tooth count.
I also have five rear sprockets, 14, 18, 21, 24, and 28 count.
I am using a 26 inch drive wheel. (This is an approximate; I forgot to measure the actual overall diameter).
The formula I found is Drive wheel diameter x front count divided by rear count, rendering a little table that looks something like this;
Gear Inches 28 38 48 14 52 70 89 18 40 54 69 21 34 47 59 24 30 41 52 28 26 35 44
For those following at home, the numbers across the top are my front rings, the numbers down the left side are my rear gears, both represented in tooth count. When referring to a gear I'll give the front ring followed by the back ring like 48/14.
Okie dokie. I've counted out my cadence, and a comfortable cadence for me right now is 64 roughly. I can sustain that speed without gassing myself out. Another formula I've found to calculate speed is gear inches x cadence divided by 336. This renders another tidbit; with this bike in high gear (48/14) my top speed at 64 cadence should be roughly 16.9 to 17MPH which I realize is hilariously slow for most of you. I can do short 'bursts' of cadence, but for just cruising, 64 is where I am right now.
First off, is my math right? Have I wasted a lot of time with formulas which are faulty? I double-checked my work a couple times and got the same answers each time, but we all know of the famed JIJO phenomena.
Second, is the gear set I have a fairly good combination front to back? It is a mountain bike, and while it will eventually be a street bike, I'd like to know if the 'jumps' are too large for somewhat efficient riding or if there are other flaws.
Now for a technique question. I know it's never good to have the chain 'crossing' at a sharp angle, like from the largest front ring to the largest rear ring. With this in mind, if I were only to use the lowest three gears on the 28 ring, the middle three on the 38 ring, and the upper three gears on the 48 ring, that means that this 15 speed bike is functionally a 9 speed bicycle, and I'm never going to have a massive effort required to get to top speed. Am I right in my thinking here?
Thanks for the help
I'd like to give you folks a rundown of my math and methods, and then I've got a couple of questions for the group.
My bike has three front rings, 28, 38, and 48 tooth count.
I also have five rear sprockets, 14, 18, 21, 24, and 28 count.
I am using a 26 inch drive wheel. (This is an approximate; I forgot to measure the actual overall diameter).
The formula I found is Drive wheel diameter x front count divided by rear count, rendering a little table that looks something like this;
Gear Inches 28 38 48 14 52 70 89 18 40 54 69 21 34 47 59 24 30 41 52 28 26 35 44
For those following at home, the numbers across the top are my front rings, the numbers down the left side are my rear gears, both represented in tooth count. When referring to a gear I'll give the front ring followed by the back ring like 48/14.
Okie dokie. I've counted out my cadence, and a comfortable cadence for me right now is 64 roughly. I can sustain that speed without gassing myself out. Another formula I've found to calculate speed is gear inches x cadence divided by 336. This renders another tidbit; with this bike in high gear (48/14) my top speed at 64 cadence should be roughly 16.9 to 17MPH which I realize is hilariously slow for most of you. I can do short 'bursts' of cadence, but for just cruising, 64 is where I am right now.
First off, is my math right? Have I wasted a lot of time with formulas which are faulty? I double-checked my work a couple times and got the same answers each time, but we all know of the famed JIJO phenomena.
Second, is the gear set I have a fairly good combination front to back? It is a mountain bike, and while it will eventually be a street bike, I'd like to know if the 'jumps' are too large for somewhat efficient riding or if there are other flaws.
Now for a technique question. I know it's never good to have the chain 'crossing' at a sharp angle, like from the largest front ring to the largest rear ring. With this in mind, if I were only to use the lowest three gears on the 28 ring, the middle three on the 38 ring, and the upper three gears on the 48 ring, that means that this 15 speed bike is functionally a 9 speed bicycle, and I'm never going to have a massive effort required to get to top speed. Am I right in my thinking here?
Thanks for the help