"How fast can it go?" - Check here to find out!
#11
10-20-2000, 09:09 PM
Your formula is actually giving the theoretical (sp) top speed of the drive train. If you were to take your Quad and drop in a bigger piston better exhaust better carb ect without changing any of the components of the drivetrain and kept the rev limits the same yes the actual top speed of the machine wouldn't change. But if the modified Quad can get to that top speed in half the distance due to the change in power wouldn't most people consider the modified Quad faster?
I do think the info you provided is very useful though. If through another method one can determine their top speed they could work the formula backwards basically to ensure that their Quad is actually making it to the top of their RPM range.
Something else to think about say you decided to put 50 inch diameter monster truck tires on your Quad. If I did the math right your top speed would then be 97.17 MPH. But how many miles would it take you to reach that speed? :-)
I do think the info you provided is very useful though. If through another method one can determine their top speed they could work the formula backwards basically to ensure that their Quad is actually making it to the top of their RPM range.
Something else to think about say you decided to put 50 inch diameter monster truck tires on your Quad. If I did the math right your top speed would then be 97.17 MPH. But how many miles would it take you to reach that speed? :-)
#13
10-21-2000, 09:09 AM
#14
10-21-2000, 12:16 PM
The formula doesn't compensate for anything. It simply tells you that if you turn this many RPM's in this gear, you will be going this fast. We already know that just because a paticular machine is rated at a certain redline, it may not actually pull that RPM. This is just bench racing for the mathamatically oriented riders. If you want to know how fast you are going you will need to take a speed rating with some type of calibrated measuring device in the field. My suggestion is to just go ride and don't worry about it.
#15
10-21-2000, 12:35 PM
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#16
10-21-2000, 05:25 PM
No it is not flawed. Your 'formula' is simply a way to find the final RPM of the final gear basically in a set of interconnected gears knowing the diameter of each and the speed of the first. If you change any of the gears in the chain it changes the final speed of the last gear or wheel. So if you simply change the size of the final gear to a much larger size then in theory, which all your little formula is, the final circumfrence(sp) will be moving at a much greater speed inorder for the fist gear in the chain to spin at its top RPM.
Like we say in the plastic biz, "Good idea, too bad the stupid computer people can't make it work."
Like we say in the plastic biz, "Good idea, too bad the stupid computer people can't make it work."
#17
10-21-2000, 11:42 PM
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The formula is indeed theoretical, which I indicated in my initial post. The math is correct. Thus the formula will produce "theoretically" correct results for any mathematical permutation of engine RPM, gear ratio, and tire diameter.
However, if plugging in a numeric value for any of the variables previously mentioned results in an impossible, or nearly impossible, construct, then the boundaries of common sense have been exceeded and the premise upon which the value for the variable is based, is intrinsically flawed.
If 50-inch truck tires yield double the top speed, then 120-inch tires from a Euclid 320 ton off-road dump truck should nearly quintuple the top speed. But why should anyone go to all the trouble of mounting such monster tires when 100,000 engine RPM is even better because it yields better than an order of magnitude increase in top speed?
The formula will provide the "theoretically" correct answer in either case, but anyone with even a modicum of common sense knows that either premise is not physically possible. Common sense therefore tells them it can't happen.
The formula was designed to provide bench racers and the curious with a simple method of approximating any quads potential top speed, its potential speed in a certain gear at a given RPM, or what effect a minor gearing change might have. All are permutations which fall well within the realm of the possible.
Like so many other tools of modern life, this one functions admirably when used as intended. But when intentionally misused, it produces unusable and irrational results. Unfortunately, just like the guy who decided to trim his toenails with a chainsaw, and lopped his foot off, you seem overly anxious to fault the formula rather than the application thereof.
While you may find it entertaining, informative, or even productive to expend your time and energy in pursuit of irrational objectives, the vast majority of people find they are much better served pursuing common sense objectives.
While "theoretically" correct, the premise of 50-inch, or 120-inch, truck tires on an ATV is every bit as empirically flawed as the premise of 100,000 RPM engines, and one does not have to be Werner von Braun to arrive at that conclusion. Every day, garden-variety common sense is more than sufficient for most folks.
In this case, the truth of the statement, "Garbage In, Garbage Out" is entirely self-evident.
Army Man
However, if plugging in a numeric value for any of the variables previously mentioned results in an impossible, or nearly impossible, construct, then the boundaries of common sense have been exceeded and the premise upon which the value for the variable is based, is intrinsically flawed.
If 50-inch truck tires yield double the top speed, then 120-inch tires from a Euclid 320 ton off-road dump truck should nearly quintuple the top speed. But why should anyone go to all the trouble of mounting such monster tires when 100,000 engine RPM is even better because it yields better than an order of magnitude increase in top speed?
The formula will provide the "theoretically" correct answer in either case, but anyone with even a modicum of common sense knows that either premise is not physically possible. Common sense therefore tells them it can't happen.
The formula was designed to provide bench racers and the curious with a simple method of approximating any quads potential top speed, its potential speed in a certain gear at a given RPM, or what effect a minor gearing change might have. All are permutations which fall well within the realm of the possible.
Like so many other tools of modern life, this one functions admirably when used as intended. But when intentionally misused, it produces unusable and irrational results. Unfortunately, just like the guy who decided to trim his toenails with a chainsaw, and lopped his foot off, you seem overly anxious to fault the formula rather than the application thereof.
While you may find it entertaining, informative, or even productive to expend your time and energy in pursuit of irrational objectives, the vast majority of people find they are much better served pursuing common sense objectives.
While "theoretically" correct, the premise of 50-inch, or 120-inch, truck tires on an ATV is every bit as empirically flawed as the premise of 100,000 RPM engines, and one does not have to be Werner von Braun to arrive at that conclusion. Every day, garden-variety common sense is more than sufficient for most folks.
In this case, the truth of the statement, "Garbage In, Garbage Out" is entirely self-evident.
Army Man
#18
10-22-2000, 01:46 AM
"The formula was designed to provide bench racers and the curious with a simple method of approximating any quads potential top speed" -Armyman 10/21/2000
"The result of these “top speed” discussions has always been a great deal of seat-of-the pants speculation supported by very few facts" -Armyman 10/18/2000
So lets see, in one statement it seems that "seat-of-the-pants speculation" is too unfactual for you. So you decide to provide us with some formula that can "approximate" it instead. Nifty.
I simply pointed out the limits of using a formula (which I did in a somewhat jesting fashion but I quess people in the "computer biz" don't understand what ":-)" means) to try to arrive at real world results. Other people have also pointed out that problems with using the formula.
I also would be willing to bet money that if you did infact put 50 inch tires on your quad and had a long enough flat paved road it could indeed reach a speed of 97 MPH. Is it impractical? Sure. Are Quads impractical? For about 90% of the owners probably. Humans ingeneral are an impractical species. So what? Does that mean that everything impractial is garbage? I don't think it does.
Oh and to answer the question you had about why not using a 100,000 RPM engine instead of the big tires its really simple. The 100,000 RPM engine isn't counterbalanced so it vibrates like heck.
Garbage in Garbage out blah blah blah
"The result of these “top speed” discussions has always been a great deal of seat-of-the pants speculation supported by very few facts" -Armyman 10/18/2000
So lets see, in one statement it seems that "seat-of-the-pants speculation" is too unfactual for you. So you decide to provide us with some formula that can "approximate" it instead. Nifty.
I simply pointed out the limits of using a formula (which I did in a somewhat jesting fashion but I quess people in the "computer biz" don't understand what ":-)" means) to try to arrive at real world results. Other people have also pointed out that problems with using the formula.
I also would be willing to bet money that if you did infact put 50 inch tires on your quad and had a long enough flat paved road it could indeed reach a speed of 97 MPH. Is it impractical? Sure. Are Quads impractical? For about 90% of the owners probably. Humans ingeneral are an impractical species. So what? Does that mean that everything impractial is garbage? I don't think it does.
Oh and to answer the question you had about why not using a 100,000 RPM engine instead of the big tires its really simple. The 100,000 RPM engine isn't counterbalanced so it vibrates like heck.
Garbage in Garbage out blah blah blah
#19
10-22-2000, 08:28 AM
