boardsNbikes
Well-known member
If you're ever in a Cheetos funk, use the brake lines as an extruder and run the lines by the right side, and magically, puff your own Cheetos :yahoo:
Gen I vs Gen II Comparison
- Thread starter ionbeam
- Start date
Help Support Yamaha FJR Motorcycle Forum:
hey! i resent that remark! more than one person has questioned my status as "people"!
05fjrBluedevil
Well-known member
Sorry could not resistAllow the following observation that might provide a new perspective.
What you state is correct insofar as those that wish to be competitive in these Long Distance events are absolutely going to add fuel cells, aux lights, hydration systems, etc. to their platform of choice. These are, in fact, critical items for what we do.
Fuel: Without 11.5 gallons of on-board fuel, you'll waste precious time refilling at the gas station, or worse, have to forgo crucial points when plotting your bonus-gathering route because you don't have the fuel to meet the necessary Time-Distance-Fuel equation to catch a ferry, get to a time bonus, etc.
Aux Lights/Water: These are actually critical safety items. At 3AM in the mountains (on a moon-less night, in the rain, etc) without powerful lights to spot the deer early enough for a controlled panic-braking exercise, you could find yourself in a Bad Way. Similarly, if you're blasting along in the 110-degree heat trying to reach Hell's Canyon for a photo, or blazing along Death Valley to get to Dante's View in time, etc, etc, if you don't carry enough on-board water keep yourself hydrated, you could start to have vision problems, or starting having issues controlling the bike, etc, etc.
So competitive Endurance Riders are GOING TO be adding these systems to their mount. This is simply a given.
The DIFFERENCE is.... even after adding all that gear, that 2006 AE rider is *still* going to have to haul around 45 additional pounds that the 2003 rider is not going to have to haul around.
Which could be very significant....
Unless said 06 rider weighed 50 pounds lighter :lol: :yahoo:
sprint_st
Well-known member
Although I agree with your final conclusion, I'm not sure I totally agree with how you got there. Yes, the theoretical braking force is dependant on the normal force or weight on the tire patch BUT the mass and velocity of the body in motion has to be overcame by that braking force. The size of the tire patch and it's coefficient of friction along with that normal force determine the total amount of braking resistance or force being applied to stop the mass of the bike at whatever velocity it is going. The brakes have a limit as to how much force they can generate to oppose the weight and velocity of the bike. The faster you go the more it takes to stop the bike and heavier it is the more force it takes to stop it. The weight of the brake components are pretty much insignificant when compared to the weight of the rider and total bike package. Also if you think adding weight helps to slow it down by increasing the braking force you must consider it is also adding to the total weight of the system meaning there is more weight to stop. And for some people who might think that is opinion, conjecture or BS, I would recommend they pick up a physics book.
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OrangevaleFJR
R.I.P. Our FJR Riding Friend
Were the riding tests performed by the same rider, or different riders? I wonder.
ionbeam
2 FUN
Sort of covered in post #7.
In the AE test, MCN says, "Interestingly, our first 2002 FJR wearing smaller front discs, stopped in just 117.8' without ABS. Yamaha clearly needs to rethink its ABS threshold to match or beat the [bMW] GT."
2006 -- heaver, linked brakes and perhaps a different ABS threshold. When the 2004 ABS was introduced one magazine (not MCN) noted that they could stop 17 feel shorter WITHOUT ABS. They said that they expect the same bike with/without ABS to normally have a 9' to 12' stopping difference and felt that Yamaha needed to make some improvements. Professional riders, same day, same track, same bike (ABS fuse in/out). As they tested various other bikes, experience showed them the 9' - 12' difference range to be industry norm. This is done on a closed course, no panic, no operator error, no dodging furry animals or Hummers, no surprise, no unexpected things like sand & gravel, or water covered painted lines, or wet leaves, or wet tar snakes........
In this month's MCN they have a bio on everyone in their staff. Fred Rau, contributor, author of the column Contact Patch says his all time favorite bike is the Yamaha FJR1300. Perhaps he was one of the test riders doing the braking test -- personal specs: 37 years riding; Height 5'10"; Inseam 29"(!); Weight 268 lbs.
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NSFJR
Well-known member
In this month's MCN they have a bio on everyone in their staff. Fred Rau, contributor, author of the column Contact Patch says his all time favorite bike is the Yamaha FJR1300. Perhaps he was one of the test riders doing the braking test -- personal specs: 37 years riding; Height 5'10"; Inseam 29"(!); Weight 268 lbs.
I guess my 06AE will stop a little quicker than Mr. Rau's, as I am exactly 100 lbs lighter than him in full riding gear, hehe. Seriously though, my impressions of the brakes on my 06 versus my 04 ABS, without the benefit of formal tests, is that the 06 SEEMS stronger.
I guess my 06AE will stop a little quicker than Mr. Rau's, as I am exactly 100 lbs lighter than him in full riding gear, hehe. Seriously though, my impressions of the brakes on my 06 versus my 04 ABS, without the benefit of formal tests, is that the 06 SEEMS stronger.
mcatrophy
Privileged to ride a 2018 FJR1300AS
Yes, given "enough horsepower" and the grip on the tyre you can accelerate just as quickly. Here in the UK, there are several small car companies that make very light cars that boast motorcycle accelerations. In the 'States, you achieve similar accelaration in a car weighing several times as much, a so-called "muscle car"."SAY WHAT?" Some numbers, please.... I suppose, if you got enuff horsepower -- you can accelerate same as a light weight vehicle, too? And, how about changing direction? Don't the 'Laws of Physics' apply anymore?
As for ABS -- it's a response to skidding tires and hyway users' inability to learn to stop (w/out skidding) -- it's not about 'better brakes'. Remember when the highway patrol used to measure skid-marks at the crash scene? It was good to have skid-marks, then!
Get "skilled", please....
We weren't talking about changing direction, but similar laws apply. Absolute cornering is all to do with exactly the same physics as braking, available grip depends on the force pushing the tyre vertically into the road. That force comes from the vertical weight. OK, a heavier vehicle won't be as "flickable" as a light vehicle (but you can help by concentrating the weight in the middle of the vehicle, one of the advantages of a "mid-engined" sports car).
As for my skill, I at least recognise that my riding ability is not perfect. And I defy ANY rider to get the best out of his bike's brakes at any time on any road surface under any weather conditions EVERY TIME. My ABS does this to probably 95%. Every time. All I have to do is squeeze. Which is what any of us will eventually do in that real, unexpected, "Oh, sh*t" moment. Incidently, my conversion to ABS came this September with my FJR, and I really am a convert.
When I came into modern motorcycling (after a 35-odd year gap), I was taught to listen for the front wheel beginning to squeel (or some other sign of complaint). I could and did practice this. In the dry. On a clean road. In the wet? On a mud (or worse) strewn country lane? That's where much of my pleasure riding is done.
OK, it's just physics.
With simple friction (say a block of wood sliding on a sheet of metal), the friction force is a function of the coefficient of friction (normally less than 1) and the normal force (that is the force pressing at right angles) acting on the wood.
The formula is Friction_force = Coefficient_of_friction times Normal_Force.
A tyre on the road is not simple friction, but near the limits (maximum braking on a dry road is something like a 5 or 10% slippage) it's not far off. And a tyre's coefficient of friction to a good road surface is likely to be a little over 1.
If you want to bring contact patch into it, my FJR's instructions say to keep the same tyre pressures regardless of load. The contact area is easily calculated, it is the weight (more exactly the force pushing the tyre down) divided by the tyre pressure (ignoring sidewall stiffness). So if you add 20% to the weight, you add 20% to the contact patch (or very nearly).
So long as your brakes are adequate, they can provide all the force necessary for any weight Yamaha says the bike can carry. OK, overload the bike and you may have trouble pulling the lever hard enough, and they will start to fade. We as riders may have physical limitations (a heavy pillion passenger pushing us forward), but the bike can still decelerate just as well (ignoring any raising of the C of G).
Certainly the faster you are going when you start to brake the longer it takes to slow. But regardless, you can expect something like a 1 G deceleration on a reasonable surface whatever speed and whatever weight, again, assuming your weight distribution is reasonable and your brakes don't overheat and fade.
Your heavy truck can't slow down as well, not because "it is heavier" but because its weight and its braking effort aren't distributed properly. When the rear wheels lock up, they can provide no more braking effort, in fact the braking from a locked wheel is less than just not locked (see later). Compare that with a bike where the rear gets very light during very hard stops, which is why the rear brake contributes much less than the front during hard braking, but we can alter the braking front and rear to suit that weight transfer. Also a large truck's tyres are required to last many tens of thousands of miles, they trade grip for longevity. It is also possible (but I expect the manufacturers will deny this) that the brakes are not really able to provide sufficient braking effort on their drums (do trucks still use drum brakes? I bet many still do).
As for skids being a "good thing", they may be for police investigating an accident, but for anyone else involved, they are definitely bad. A locked-up wheel on a dry road has less than 80% of the best braking available. On a wet road it's less, depending on how much water there is under the tyre. A locked up wheel also has no directional stability. (Nor has a wheel that is at the absolute limit of braking, it has to share cornering and braking grip. ABS allows some sharing of this, at least in a car, I've not seen any reports of trying to steer a fully braked ABS bike).
If you still don't believe that weight makes no difference to fundemental braking ability, remember that almost any normal high performance car weighs many times the weight of a bike, but its braking ability is very similar to a bike. And you can take a light car or a heavy car. If it's properly designed for performance, its braking will be always within a few percent the same. And the same as a decent bike. And, yes, a few high performance cars have motorcycle acceleration, even though they are heavier. They just lay more power down.
Just to add, I know a dragster slips its tyres during its maximum acceleration. Things are a little different here, it's laying down near-molten rubber that is providing "stiction" rather than friction. This also means the normal friction laws don't apply, lighter can be better. And I don't see a dragster doing several thousand miles on a set of tyres. While motorcycle tyres are a bit stickier when warm, they don't actually melt into the road surface.
Sorry if this is a bit lengthy and disjointed (preparing for general flaming), but I hate to see these beliefs propogated. It's a bit like the "drop a cannon ball and a feather down an evacuated shaft". Instinct says "The cannon ball is heavier, it will fall faster". But it doesn't, they fall with the same acceleration. 1 G. Instinct can be deceiving.
KUDOS to MCATROPHY for his completely correct informational post regarding bike weight versus stopping distance.
The idea that bike weight is tied to stopping distance is a great example of the fallacy of 'conventional wisdom'. 'Conventional wisdom' becomes such because it is easy to believe and is promoted widely. Not because the underlying 'wisdom' is true or correct.
For more proof, compare braking distances of heavy touring bikes to much lighter 600cc sportbikes.
Regarding the ABS distances, as previously mentioned, it all depends on the threshold that the system is set to activate at. If the systems takes over at .8 G, it is impossible to improve the distance the bike stops in (on that day/tire/weather-road condition) no matter what the rider does. The rider can lengthen the stop by releasing brake lever pressure, but he/she cannot increase braking beyond the .8 G as the ABS is at that point cycling the braking pressure. And the ABS system doesn't cycle the pressure to a level beyond its' threshold. A well-trained rider on a non-ABS (or the ABS turned off) bike, with the same tires, road conditions etc., could beat the ABS bike as long as the ABS threshold is below 1G (the accepted max for deceleration on today's tires).
Jed
The idea that bike weight is tied to stopping distance is a great example of the fallacy of 'conventional wisdom'. 'Conventional wisdom' becomes such because it is easy to believe and is promoted widely. Not because the underlying 'wisdom' is true or correct.
For more proof, compare braking distances of heavy touring bikes to much lighter 600cc sportbikes.
Regarding the ABS distances, as previously mentioned, it all depends on the threshold that the system is set to activate at. If the systems takes over at .8 G, it is impossible to improve the distance the bike stops in (on that day/tire/weather-road condition) no matter what the rider does. The rider can lengthen the stop by releasing brake lever pressure, but he/she cannot increase braking beyond the .8 G as the ABS is at that point cycling the braking pressure. And the ABS system doesn't cycle the pressure to a level beyond its' threshold. A well-trained rider on a non-ABS (or the ABS turned off) bike, with the same tires, road conditions etc., could beat the ABS bike as long as the ABS threshold is below 1G (the accepted max for deceleration on today's tires).
Jed
fun watching this: :argue:
And just to add: I think it matters what brand of brake fluid is in your ABS system......
That should get a new argument going.....
Iggy, pass the cheese. TWN, Brewskies and finger san'wiches coming up!
And don't sit in my favorite chair. :nono:
And just to add: I think it matters what brand of brake fluid is in your ABS system......
That should get a new argument going.....
Iggy, pass the cheese. TWN, Brewskies and finger san'wiches coming up!
And don't sit in my favorite chair. :nono:
RacinRay
Living The Dream
:drinks: Can't we all just get along? :drinks:
What's next...questioning the legitamacy of one's birth?
What's next...questioning the legitamacy of one's birth?
fjrchik
Just a girl in the world, having rode 3 FJRs
jeez. why the hell did i read all that?
sprint_st
Well-known member
Where in the hell do you guys come up with this stuff. The cannonball analogy is totally out to lunch because it has to do with the force of gravity and is totally different from the problem of mass traveling at a velocity being opposed by frictional forces. Also the original comment had to do with the weight of the brake components NOT the weight of the bike. The weight of the components is statistically insignificant. The weight of the bike/rider system is at the heart of the matter. I will readily admit I don't design ABS systems but setting ABS threshold on a deceleration factor such as 1g doesn't make sense to me. The object is to make the brakes not lock up. Sensors do that by sensing the rotation of the rotors not measuring deceleration.
twowheelnut
R.I.P. Our Motorcycling Friend
fjrchik
Just a girl in the world, having rode 3 FJRs
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Errm, the ABS system compares the speed of the rear tire and the speed of the front tire, if the two do not match within the margin of error the system engages by pulsing the brakes, since the brakes don't completely lock stability is increased.
I still want to hear about Warchild's R1, bah.
JS
I still want to hear about Warchild's R1, bah.
JS
Bustanut joker
Well-known member
Jeezus Ke-rist
What did all that bitchin accomplish 'cept to get a few guys drunk and cheeze fartin' :stink: :stink:
Just ride the fukers :glare:
Hell I lost half an hours ridin time just readin this sillyness B)
:jester:
What did all that bitchin accomplish 'cept to get a few guys drunk and cheeze fartin' :stink: :stink:
Just ride the fukers :glare:
Hell I lost half an hours ridin time just readin this sillyness B)
:jester:
FJRay
Well-known member
If you are good, you can get in a pretty good nap in the three pages of educated pontification in this thread. Thank you very much
Warchild
Benevolent Dictator
Soon as I recover from laughter at this thread..... ooooo, my sides hurt.... :lol: :lol: :lol:
Bearly Flying
Well-known member
Bustanut:
She ain't over yet, pull up a chair. These Guy's are smarter than old Isaac. (E=mc2)
Can't wait to see what other " Conventional Wisdom", Old World misconceptions we've been hanging onto.
She ain't over yet, pull up a chair. These Guy's are smarter than old Isaac. (E=mc2)
Can't wait to see what other " Conventional Wisdom", Old World misconceptions we've been hanging onto.
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