Math Question ...

#1
My friend has a math question on a test .... anyone know the formula?

Information given:
Sprocket = 24 teeth
65 Mph
2000 RPM

What will the speed be with a 25 tooth sprocket?

Thanks!
Kevin
 
#5
Not smart.....all things being equal, a 1 tooth difference on the sprocket always equates to a 2 MPH difference at 2000 RPM. No formula used.
 
#9
I told my friend I thought you would need wheel diameter to complete the formula but he said that was all that was given.
Seems to me that if the wheel diameter was say 30 inches the speed difference would be different for a 10 wheel with the 1 tooth gain.

Been years since I was in college.
 
#10
I had my friend Randy look up this question online.
It reads verbatim:

"Ratio and Proportion. A 24 tooth front sprocket on my motorcycle gives a speed of 65 mph at 2000 rpm. Calculate my speed at that same rpm with a 25 tooth front sprocket."

He needs to know how to calculate this.


Thanks
Kevin
 
#12
We know it will go faster with the 25t front sprocket, so the ratio is 25/24 x65=67.7 mph

Man, this stuff is hard. College was 55 years ago, but I think I'm right. Simple % change, 25/24
 
#13
Simple algebraic formula , what ever you do to one side you do to the other !24 over 65 is equal 25 over X .cross multiply then divide.
 
#15
RPM doesn't make a difference in this case, it's constant in both variables.
Chipper is right, just set it up as a ratio and cross multiply
 

Bikerscum

Active Member
#16
We know it will go faster with the 25t front sprocket, so the ratio is 25/24 x65=67.7 mph

Man, this stuff is hard. College was 55 years ago, but I think I'm right. Simple % change, 25/24
Doh! I missed the front sprocket part, but I think the approach is right.
 
Last edited:
#19
useng1 and chipper: Randy lit right up when he reviewed your answers and how they were explained.
He is a fixture building apprentice and just started his Machinery Handbook 29 class and this was on a test.
When he gets his result I will post it here.

jbrocks you and I are on the same page! I am a die maker and went through all the apprentice classes and got mostly A's and one B, my only C was in math!
 
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