Sprocket Size vs. Performance

With more teeth/roller contact friction increases

Agreed.

The only advantage to this is reduced chordial rise, but chain wear increases. The chain will run slightly smoother.

Agreed. But we’re talking performance not wear issues.

#1 is true, #2 and #3 need clarification, #2 are you talking about friction, if not more force to the chain is a good thing. #3 the axle sprocket imparts torque in relation to the front sprocket it does not act alone.

2 and 3 are in comparison to a bigger driver/sprocket pair. I agree with your comment.

Larger is a weight increase, flywheel effect only applies to run down time, accelerating a weight and maintaining it's speed consumes energy, although they do store energy, no gain while engine is pulling. Less unsprung, rotating mass is always a good thing.

I think you agree the larger driver/sprocket combo consumes more energy in acceleration, and has higher inertia at equivalent speeds compared to a smaller pair.

this is a fictious force that acts away from the center point of a rotational object, what role does it play here, you could increase it by 200% it will not make you faster

Very good, it is a fictitious force, which I used to highlight inertia differences, but did I imply it makes you faster?

Show how you arrived at the sprockets producing these energy quantities and why did you add them together. Just not enough information to make an conclusion.

This is good place to start your own comparisons:
http://www.calculatoredge.com/mech/flywheel.htm

Thought experiment:

Let’s say we could run a 10T driver and a 10T sprocket vs. a 100T driver/100T sprocket-both 1.0 ratios. Still think the performance would be the same? I think it’s very myopic to conclude that the analysis of drive train performance simply stops at the ratio.
 
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Why do people keep asking the same question year after year? why not just try it and time it with your stopwatch? Also why with what is essentially marginal H.P. is frictional losses never mentioned? Try it , I did and I know.

Jack, You are trying to teach people something that don't want to be taught. You bet there is a difference..... Now, all of you Dyno Experts (and from what I have read so far, most of you have never seen a Dyno let alone run one for a lot of hours) put the smallest possible driver on your engine and make a couple of pulls. Then put the largest possible driver and repeat the process and watch what happens to the curve. If you don't see any change, get your Dyno repaired...
 
Jack, You are trying to teach people something that don't want to be taught. You bet there is a difference..... Now, all of you Dyno Experts (and from what I have read so far, most of you have never seen a Dyno let alone run one for a lot of hours) put the smallest possible driver on your engine and make a couple of pulls. Then put the largest possible driver and repeat the process and watch what happens to the curve. If you don't see any change, get your Dyno repaired...
You are stating simply change the drive gear?
 
Okay, here is the deal. I started this thread to gather opinions and I really appreciate the input. I want to state that I am of the ratio is a ratio school and my biggest concern when choosing sprocket combinations is ground clearance !! I race quite a bit and have a very good sense of where I am in regards to the competition. Last race I qualified 2nd with the two behind me within .004. Number 1 was .4 faster. Why? Part of it is that I'm at least 45 years older, at least 6 in. taller. We are both at the minimum weight (370). I have been running a 16/56 sprocket combo but this week will use a 18/63. I could care less what dynos tell me. Being a lifetime drag racer I know their value. In this case only on track performance means anything to me. I really don't expect to see a difference. Will be delighted to see a .3 improvement. ( Ha!) Will post results of the experiment ASAP. By the way, this is on a fairly high speed sprint track.
 
I have been running a 16/56 sprocket combo but this week will use a 18/63. I could care less what dynos tell me. Being a lifetime drag racer I know their value. In this case only on track performance means anything to me. I really don't expect to see a difference. Will be delighted to see a .3 improvement. ( Ha!) Will post results of the experiment ASAP. By the way, this is on a fairly high speed sprint track.
What would really be nice is if you could tell us the air density during which both tests were run. The temperature and the barometric pressure, (air density) do make a difference.
 
Okay, here is the deal. I started this thread to gather opinions and I really appreciate the input. I want to state that I am of the ratio is a ratio school and my biggest concern when choosing sprocket combinations is ground clearance !! I race quite a bit and have a very good sense of where I am in regards to the competition. Last race I qualified 2nd with the two behind me within .004. Number 1 was .4 faster. Why? Part of it is that I'm at least 45 years older, at least 6 in. taller. We are both at the minimum weight (370). I have been running a 16/56 sprocket combo but this week will use a 18/63. I could care less what dynos tell me. Being a lifetime drag racer I know their value. In this case only on track performance means anything to me. I really don't expect to see a difference. Will be delighted to see a .3 improvement. ( Ha!) Will post results of the experiment ASAP. By the way, this is on a fairly high speed sprint track.

Fairly high speed, that's scary fast. ... :)

I can't imagine you coming back and not telling us the 18/63 was better. IMHO, it will be better and I can't imagine it not being better.

I'd also think it would be great if you could report back to Al on the air density too.
 
You are stating simply change the drive gear?

No, I thought you could figure that part out.... Keep the same ratio.

OKAY, HERE WE GO.....

First Pull: 13 Driver 52 Axle

Second Pull: 18 Driver 72 Axle

Now, if you do the pulls one right after another, the temperature, barometric pressure, and humidity will not change enough that you will have to figure the corrected HP/Torq (Regardless the curve will still change it's location in the RPM range. With the small driver, it will be at a lower RPM at you max HP). The overall HP will not change much.
 
NO? ... on this forum we eat live and breath everything you say on here is gospel truth!
As we all with bated breath, await your definitive explanation to bring this to a clearly explained conclusion. Some of us will need you to type slowly so we can keep up.
 
Be sure and wear your lucky underwear and socks. But, I don't have to tell you how important that is. And make sure you eat that special meal the night before, and only drink the yellow Gatorade, cause the red will slow you down. If you test them back to back, the yellow is good for .2. We all know the red is for Jr drivers.
 
As far as air density, it's the same for everybody on track at the same time. It's over 105 deg. here, 5% humidity, this time of year our adjusted altitude is about 4000' ( actual elevation is 1200'). As I mentioned I'm aware of where I am performance wise compared to the field, improvement is what I'm looking for.
 
As far as air density, it's the same for everybody on track at the same time. It's over 105 deg. here, 5% humidity, this time of year our adjusted altitude is about 4000' ( actual elevation is 1200'). As I mentioned I'm aware of where I am performance wise compared to the field, improvement is what I'm looking for.

Rationalization. I don't have the air density gauge, cost/benefit is too low, ergo, I will guess. There is a track in Paris California, close to the desert, where I have seen the air density change seven points from late afternoon to early evening, when the sun went down. You cannot feel that air density change. Oh sure it cooled off after the sun went down, and you can guess that the air density went up, but you don't know for sure.
 
Rationalization. I don't have the air density gauge, cost/benefit is too low, ergo, I will guess. There is a track in Paris California, close to the desert, where I have seen the air density change seven points from late afternoon to early evening, when the sun went down. You cannot feel that air density change. Oh sure it cooled off after the sun went down, and you can guess that the air density went up, but you don't know for sure.

You are correct Al, but what part of "it's the same for everybody" did you miss?
 
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