Sorry, your very right.
Coefficient is kind of like the defining a variable as final in some programming languages. They never change and can't be changed at anytime within the program itself. The friction is increased between the rubber and the surface because of the width of the tire and also possibly the tread pattern and depth. All in all that has awlays been one of the downfalls of a dirtbike. Well all of them except the old Yamaha 200 bike.

 

Historical maybe but deffinately hysterical [img]i/expressions/face-icon-small-smile.gif[/img]

Maybe dirt liars could have got more desirable results if they just pulled the plug wire on the YZF.

How can anyone buy into the idea of a better suspended, considerably lighter and more powerfull machine being beat, I cant wait to hear the screams!

 

Physics is physics. 100 foot jump is plenty for me. After that, going to the ER might not even save you if you go down.

 

100 feet is definately plenty.

 

I thought this has already been addressed plenty of times. A MX bike can not beat a top of the line MX quad in cornering. Light is good for the purpose of nimbleness, and flickability, but weight is counter productive when your dealing with traction. The less something weighs the less traction it gains. There is a balance between weight to power ratio. If you get to light it would be like putting a 50hp motor on a 10 speed bicycle. The bike would do nothing but spin the tire and you wouldn't go anywhere. An ATV deffinately has the edge on the MX bike in traction. A point to ponder how many 60-80hp MX bikes do you see out there? How about none! Thats why I say bikes have met there time and they really can't gain any more in R&D that is going to substantially change or revolutionize the industry. ATV's on the other hand, give some time they will surely surpass dirtbikes soon in the industry.

 

No.

Weight is never counter productive to traction unless you are on a material in which you need to "sink down". On say, pavement or gravel, less weight will also be better.

Yes, on a light machine the normal force is less, but you are overcoming less inertia.

If you aren't convinced, I would recommend going through the calculations. Start with "F=ma".

(Not that a quad wouldn't have the edge in cornering, but it's not weight that does it.)

 

Ok, so dirtbikes have "met their time" cause quads have more traction. Yeah, ok. Give it up man. You are wrong. Just live with it.

Because quads have a bigger "contact patch" and they are better in cornering. That will be the demise of bikes. LOL Oh, and bikes can't get any better then they are now.[img]i/expressions/face-icon-small-confused.gif[/img]

 

Overcoming inertia via smaller engine parts and less mass has little to do with the acceleration and traction. Another words it makes vary little difference when dealing with over all performance. The big factors are contact surface, and hp/torque curves. Don't think just because you can use the terms inertia and "F=ma" that it makes you sound any more intelligent. Force can be looked at in the aspect of hp/torque requirements and getting the power to the ground, but your example has little to do with transfering the power to the ground. Getting the power to the ground has everything to do with contact, tire specifications. Anybody can build a super hp motor. What difference does it make if you can't use it. Again, have you ever seen a 60-80hp pro MX bike? Nope! Have you ever seen a 60-80hp MX ATV? yep! I have one in my garage.

Another point I would like to make...you said "Weight is never counter productive to traction unless you are on a material in which you need to "sink down". "

Although vary vague and I'm not sure what your trying to say here, I have been in the race industry for many years, and there are many factors in racing, but if your trying to say that to little weight can not be counter productive in regards to traction your vary wrong. In drag racing, if your car is to light and your turning to much hp and torque, you will literally sit still while your tires are turning at 9,000 revolutions per second without going anywhere. This is a big problem even in sport bikes racing. You ever here of counter stearing? This is a fairly new technique involved where your laying into a curve you literally twist the throttle and spin up the back tire until it heats up and spins up and catches traction and you literally get slinged out of a corner. IT used to be pretty uncommon but now almost every AMA SBK racer uses the technique, at least in the full liter bike class.

Now, to much weight obviously can create traction problems too, but so can to little weight. Thats why I stick to my guns and think other than changing composite materials and tweaking suspenions there is very little to do with dirtbikes, and I don't see any major changes in the near future that are going to completely revolutionize the dirtbike industry. Its pretty much peaked out. Now ATV's on the other hand, we are light years behind technology and what we can do. Just wait until an ATV version of the sport bike is allowed on the streets. Could you imagine a 160hp ATV set-up running against a gsxr 1000? I'm sure its only a matter of time. The dirtbike days are pretty much numbered.

And don't get me started on ATV's out braking MX bikes because of there larger contact surface...

 

Ever heard of the CR500 or KX500? Modded, each will EASILY produce better then 60 HP. My modded YZ250 got over 50HP.

Do you see quad races selling out 60,000 seat stadiums? Nope. Maybe I'm not looking close enough, but I haven't seen a single quad race on tv. I don't see any pro quad racers doing TV commericals, do you? Event money (supercross, moto-x, x-games, gravity games, etc), sponsorship money, tv coverage, and rider salaries have never been this high. Ever! And they keep going up. If quads are so much better then bikes, how come they are not dominating the industry? Funny thing is, they sell more quads then dirtbikes. Yet the bikes are still more popular. Maybe with the "intelligence" you gathered from your years in the racing industry you can fabricate some scientific BS reason for that.

No doubt ATVs have come a long way and are progressing even further every day. But to say bikes are going to be phased out and "their days are pretty much numbered" is beyond ignorant. And how many bikes have you seen banned lately? None! How many quads have been banned recently? Hmmmm, the Banshee comes to mind. Phased out by 2006 IIRC.

 

OK OK OK OK LMAO I give in and will be trading in my quad for a heavier underpowered one to lower my lap times ASAP [img]i/expressions/face-icon-small-happy.gif[/img]

I know what you are talking about with contact area and proper weight distribution etc but lets accept that no one wants to add a few hundred pounds to their race machine no matter what type it is. The trick is properly setting it up to use the weight avail and cause the transfer of that weight to where its needed at launch but then were not talking about pro stock or top fuel here are we.

Though the added contact area of the wider and additional tires will have a deff effect on traction and handling this as noted before will mostly only be prevalant in the corners (I do agree that a quad does or can have an advantage in cornering) or on certain more slipperly surfaces, and will not be a benefit to the other aspects of a MX or XC race.

The added weight of the quad and added unsprung weight of the heavier front end, swing arm, axles and extra wheels etc is a deficit to acceleration and handling thru whoops and ruts etc. and this is why (and especially if you ride stock suspension) if you ride with any newer bikes that your friends whisp past you in the deeper whoops and other riugh sections waving while you hold on for your life.

A quad and a bike are very different machines (more so than I ever believed before owning a quad) and sadly we get the short end of the stick over and over. Dont believe me then go out and purchase a new pair of them and see which one is better prepared to ride hard or race in stock condition. I think I have spent more time preparing my quad to handle or ride thru the rough stuff more like the way my old CR did than anything else. It just not right that we spend more $$$ and then get our ***** kicked thru the rough sections that would have been no problem on the two wheeler. Then add in the lower tech and poorer power to weight ratios and we get the honor of spending thousands of dollars to get out quads to perform properly (well as close as the industry will allow us since a lot of the info on getting this all right is either very expensive or not being shared with us).

I didnt and still dont want to get into the "why" a dirt bike handles and accerates so much better issue but was just pointing out that we cant believe most of what we read and need to use our brains that god gave us to read between the lines and see what is advertising and what is possibly fact.

What kind of a comparison was this mess anyhow? I wondered when reading this since they gave up that they removed most of the course from being used that how much more was changed to affect the outcome that we didnt hear about. I just hate the "pretty" tests that are done and seem to overly favor the major advertizers in the wording and results, and its borderline shamefull how its sometimes done.

Now I have limited experience with both these machines but I can tell you that they are both excelent and rank in the tops of their markets. Yamaha has outdone themselves with the new quad and it hopefully will re-spark the interest in making a trure high performance quad that Cannondale started, and the only winners here are us as we will be truely getting much more for our $$$ and possibly sometime in the future not need to immediately drop thousands into suspension and motor mods to make them right (sorry but the YFZ still needs both these mods) but when is still to be seen.

Sorry for the long post but I saw that my short one left to many questions [img]i/expressions/face-icon-small-smile.gif[/img]