How is Overdrive % calculated?

[Panther6834]

Well, DRED805 has had more then enough time to reply, but he had chosen not to...possibly because he's not willing to "back up" his claim of "the other formula", possibly because he's worried that said other formula will be proven 'false', possibly because he no longer cares. Whatever the reason, no worries, and I accept his choice. It wouldn't be the first time something believed by many to be 'true' was (eventually) proven 'false'...and, I'm sure it won't be the last (there are still lots of things in this universe believed to be 'true' which might not be). And, no, I'm not talking about religion (tho, I could have). Think of Theranos, and all the people who truly believed Theranos was capable of providing exactly what they claimed. I'll leave the rest of that one alone.

Anyway, I've decided not to wait for DRED805's answer. If he's willing to accept the "challenge", great...the video is already done, and has been uploaded for everyone to view. If he's not willing to accept the possibility that the 'formula' he (and others) have believed to be accurate could actually prove false, that's his choice...but, the undeniable proof is now available for everyone to watch. For those who want to watch it, go for it...in fact, I encourage you to watch it. That way, no one can try and claim that I might have "fixed" the results.

https://youtu.be/oV88h_Oxgw0

And, for those who don't feel the need to watch the video...for those willing to accept the facts proven in the video...here are the results:

The T-case in the video has a 20T pinion (the "driving" gear, also turning the rear output shaft), and a 14T spur (the "driven" gear, turning the front output shaft). With the rear-output/front-input shaft rotating 100x, the front-output shaft rotated just under 143 times. That is indisputable proof that the front OD is just under 43%. As such, the 42.85714286% I mentioned in a post earlier this morning would be 'correct'...and, the 35%, as determined by the 'other' formula, is proven to be inaccurate. Again, NO 'formula' was used to make this determination...it was simply counting rotations in the above-linked video...and that figure IS indisputable.

Now, it is possible that the reverse is accurate...that the UD to the rear (compared to the front) is 35%. IF that's the case, then the formula presented by DRED805 would still be correct...except that said formula would be correct for calculating rear UD, and not front OD. Honestly, I do not know, nor am I interested in determining such, as rear UD was never what I was interested in determining. In the matter of a 20T/ 14T combo, the front overdrive IS (approx) 43%, not 35%.

The 'downside' of all this is that I now have to go back over all 46 potential front tires, calculate the potential "rear tire circumferences" matches based on a 42.86% OD, and then determine which of the 19 potential rear tires would work. Work the previously-known OD percentage possibilities (15%, 27%, 30% & 33%), there were 295 possible front/rear tire combos that could have worked. With this 42.86% OD possibility, whoo knows how many more potential front/rear tire combos will be added.

--------------------

I'm going to say this one last thing, and then I'm going to leave it be...especially considering the video I just posted a link to is all the "proof" that's needed.

Just because "someone in the industry" came up with a 'formula'...any formula...does not mean, or prove, that said 'formula' is correct. Throughout time, there have been countless formulas, as well as theories, that were believed to be "true", and people would even fight (sometimes physically) to prove the formula's/theory's 'validity'. It can get too a point where people blindly follow a formula/theory, without actually bothering to fully verify it's accuracy. It's no different than all the people who blindly follow Trump, refusing to accept things said against Trump, even when undeniable proof has been presented.

There was a time the people of the world believed Earth was flat. They'd been told, over & over, and were even presented with 'proof', that Earth was flat...and anyone who attempted to prove otherwise was ostracized. Thankfully, there were enough intelligent people who, over time, continued providing proof that Earth was NOT flat. No one knows (because they're long-since dead) how dumb those "flat-Earthers" must have felt when they finally *knew* Earth wasn't flat.

I remember one of my university courses many years ago...an astronomy class...where, one day, while giving a lecture, the professor stated something (honestly, I no longer remember the specifics...but, I do remember the general nature of what what said) having to with the curvature of Earth's surface, and the curvature of the moon's orbit. Throughout most of the remainder of that lecture, I kept thinking to myself that the data the professor gave was wrong...but, I didn't know "how", or "why".

At the end of class, I went up to the professor, and questioned him on it. Like the others in this thread, who keep telling me to 'accept' the formula, the professor was astonished that he was being questioned on this. After all, he was teaching something that had been taught to him, and by an astrophysicist of some notoriety. However, to (I'm guessing) "keep me happy", he told me that, if I could prove him wrong, he'd present the data to the class.

I spent a good part of that weekend testing formulas (which wasn't easy, as I was having to combine decimals with fractions that had no finite decimal equivalent). I was NOT trying to prove the professor "wrong". In fact, I NEVER wanted to prove him "wrong"...I just wanted to know what the "right" answer was. Come the following week, after trying my best, I presented what I had come up with to the professor. I told him I was unable to figure everything out, due to the decimal-fraction matter...but, that I knew my results were off by no more than a few percent...and, at the same time, that what I came up with was drastically different than what he had presented the previous week.

As promised, he presented my work to the class (without giving me credit for the work, which I never wanted). Even better, he spent the next could of weeks trying to obtain a more accurate answer, to which he succeeded. The point is, in the end, something that was believed by thousands (possibly hundreds of thousands) to be "correct" was, ultimately, proven wrong...and, thankfully, the TRULY correct answer was discovered. However the ONLY reason this was achieved was because someone 'challenged' what had been previously (and falsely) believed, and because a LOT of time was spent to determine the TRULY correct formulas, and the accurate answer

The point of everything above is this - I am NOT, nor have EVER, been trying to prove DRED805 "wrong". All I have been trying to do is determine what the correct answer/formula is. I presented data that, even with the most basic of mathematics, proved that the 'formula' couldn't be correct. I was NOT proving DRED805 was wrong...I was proving that the 'formula' was wrong

Believe whatever your want...of the formula, of me, of anyone who contradicts you..."right", or "wrong", you are free to believe whatever you wish. As for me, it matters not what you choose to believe - think the best of me, think the worst of me, I could care less. Why? Because opinions are like...yeah, you all know the remainder of that saying, so no need for me to finish the quote.

~ More peace, love, laughter, & kindness would make the world a MUCH better place

[Fricker08]

You obviously got enough time on your hands while I know for a fact [mention]DRED805 [/mention] is working
“swinging a hammer like an idiot” and that’s why he hasn’t responded. So enough with the attitude, you made your point. Now move along.


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[Panther6834]

Originally Posted by Fricker08

You obviously got enough time on your hands while I know for a fact [mention]DRED805 [/mention] is working
“swinging a hammer like an idiot” and that’s why he hasn’t responded. So enough with the attitude, you made your point. Now move along.


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Today is my day off...the first day I've had off in almost two weeks...and, tomorrow, I'm back working. As for the "swinging a hammer" comment, you seem to have (purposely?) ignored his comment which led to me comment. Also, his comment was squarely targeted directly at me, whereas my comment was (somewhat) "generalized". If you read the comments, you'll notice who started with the 'attitude'.

As for the "moving along", I plan to...have easy to many calculations to make to waste time commenting to someone (not referring to you, obviously) who refuses to look at things from more then one direction. To successfully make it through life, one needs to learn to "look at things from multiple points of view"...oh, yeah, and "have a good sense of humor" (also important to making it through life successfully).

~ More peace, love, laughter, & kindness would make the world a MUCH better place

[ScaleLifeNewbie]

This guy has to be trolling by now. I refuse to believe anything else

[ferp420]

but the only thing that matters is having fun right

[Panther6834]

Originally Posted by ScaleLifeNewbie

This guy has to be trolling by now. I refuse to believe anything else

I don't, nor do I have any reason to, "troll". My initial question...which is the title of this thread (created by someone else)...was an honest question, needing an accurate answer. And, the video provided said answer. Besides, IF I was "trolling", WHY would I have bothered going through all the trouble (and time) to create & post the video?

Originally Posted by ferp420

but the only thing that matters is having fun right

Got that right.

~ More peace, love, laughter, & kindness would make the world a MUCH better place

[DRED805]

Holy moly.

I didn't read any of your novels, and I don't know what the challenge is supposed to be. But you're the worst.

[Fricker08]

Originally Posted by DRED805

Holy moly.

I didn't read any of your novels, and I don't know what the challenge is supposed to be. But you're the worst.

Holy moly! I just realized you can block people on here! I don’t have to see anymore of his posts… it’s Christmas in August!


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[OSRC]

Originally Posted by Panther6834

I'll also bring the "project" that this whole OD situation was about. The reason (as stated in another thread) for knowing the front OD has to do with running different diameter front-rear tires. The front will be running smaller diameter tires on 1.9s, and the rear will be running larger diameter tires on 2.2s. The 'problem' (all along) has been to help determine what those tire diameters need to be, as I don't want to "drag" the front OR rear tires.

JFC, as explained multiple times in that thread, calculate the gearing and tire circumference front and rear - problem solved. It's not complicated and it has nothing to do with the ratio front to rear. You don't need them mean, the average, percentage, or any of that crap, just gear teeth, tire circumference and basic math. I even spent 45 minutes doing the math and working on a formula for you as an example, and you flat ignore it, and then set out to explain why the method you came up with is superior somehow. Then why ask? Nothing infuriates people than putting out a thread asking for feedback or help, and then frankly pissing all over that feedback. And now you still say you don't know?

Good luck with your project.

[Kemora]

This all comes down to percent change vs. percentage difference. Standard way to calculate overdrive is percentage difference. Both Vanquish and Axial do it this way.

Good explanation from Math.net:

"Percent difference, percent change, and percent error
These three measures, though similar, are not interchangeable. They are used in different contexts.

Percent difference

Reference value: neither value has any obvious precedence over the other, so the reference value is the average between the two.
Example: if we have two sticks, one with length 100 cm, and another with length 50 cm, we can calculate the percent difference between their lengths.
Percent change

Percent change assumes that there is an "old" and a "new" value and compares values relative to the old value. So, the reference value is the old value, and percent change is used to determine whether the new value is the same, an increase, or a decrease, relative to the old value.

Reference value: old value.
Example: if we have a plant that grew to being 60 cm tall from 55 cm tall in some time period, we can calculate the percent change in the plant's height over that time period with 55 cm being the old value, and 60 cm being the new value.
Percent error

Percent error is mostly used in more scientific settings. In the context of experiments, percent error is used when there is some known/theoretical value being compared to an experimental value.

Reference value: expected value
Example: Say we have a factory manufacturing a part that is supposed to have a length of exactly 10 cm. If a part was manufactured that had a length of 9.5 cm, we would use percent error to measure how large a difference there is between the expected length and the length we actually got.
So, in all three measures, we are comparing the difference between two values to some reference value. The difference between the three is what the reference value is, which affects which of these measures we choose to use."

[Fricker08]

Kemora, that’s a whole lot of reading that I’m sure makes sense to way more people than me. All I know is the start of this post was to figure out where vanquish came up with 33% od when it it seemed like much more. They have since openly admitted they screwed up but did not change any product info on it


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