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Old 04-21-2003, 11:18 AM   #21
jmeyn
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Default Apple vs. orange

Camry/Miata comparisons aren't very important but in fact, the two can brake at the same rate given the right tires, hardware and rider skill. The contact patch area is nearly exactly a function of weight and tire pressure; the maximum braking force depends on the coefficient of friction of the tires. For practical (as opposed to impractical sticky drag race surfaces) purposes the best any bike or car can do is about 1 G. This scrubs off about 21 mph per second.
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Old 04-21-2003, 11:42 AM   #22
F451
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Default Data Hooey

Don't need it or want it. Why? Manufacturers' are prone to slight or even major changes that affect hard data during the life of a motorcycle model. Much more interested in the year-to-year changes; the safety of the motorcycle; the long-term rants and raves of a model; don't care about resale, horsepucky, or riding clothing styles.



Other than that I look for the journalist style and rider reviews that best suit my interests and riding style and follow his or her journalism. And my main concern with any motorcycle is whether I personally like it or I can't wait to get rid of it. Hard data be danged.
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Old 04-21-2003, 11:48 AM   #23
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Default Re: Why don't motorcycle journals present hard data?

Even more so than with cars, bikes seldom spend any time at constant cornering mode (125 gp bikes might be an exception) -- they are braking deep into the turns, usually almost to the apex, and almost immediately past the apex, the rider is starting to roll on the throttle. It is the bikes ability to corner and brake simultaneously, or to accelerate and corner simultaneously, to provide the best feedback to the rider so that he/she can find the limits that makes a great-handling bike.



You do mean at the track, don't you Bob? I hate to count the cost in good people of riding like that all the time.



The line you describe above is not the ideal line used for 125 and 250 cc racing. They brake from straightaway speed to max cornering speed, transition from braking to pure lateral acceleration in the corner, hold that mode past the apex to the outside of the track and transition back to pure forward acceleration.



Anyhow at maximum cornering speed for a given radius, any force applied to the rear wheel whether braking or accelerating causes the wheel to spin. It's during the transition from straight line to full cornering speed that simultaneous power delivery happens. The time spent in transition goes up with weight; both 125 and 250 cc GP bikes can approach the "ideal line" (See Keith Code) but heavier, more powerful bikes use more complicated high exit speed lines to make up for their slow transition speeds.



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Old 04-21-2003, 11:54 AM   #24
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Default Re: Why don't motorcycle journals present hard data?

Bike tests in MCN are the reason I subscribe to them. Between MCN, MO and Rider I find I can get as much usefull information as possible without actually riding the bike. The other print mags are pretty much flash and ego-stroking for the editors. The info I value is the dyno charts which tell where the power and torque is, the braking tests, the roll on acceleration test and any comments on undue vibration or weird ergo's. The chart in MCN test that show the bar, peg and seat measurements is handy also. Any other info such as strip or track tests are, for me, pointless as thats not how I ride and the results are too subjective to be any real use anyway. I do see the value of track comparo's of sportbikes for people who value performance over anything else, I'm just not one of them.
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Old 04-21-2003, 12:00 PM   #25
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Default Re: Why don't motorcycle journals present hard data?

I'm thinking that some poeple are just dog lazy. Within 5 minutes of looking around the MO site I was able to (and I'm using the R1 and R6 mentioned above as an example)


[*] find out how fast they go with regards to top-speed, 1/4 mile, road course lap times, and race course lap times.
[*]more numbers representing their wet weight, displacement, stroke, bore, geometry, etc... than I'll ever need to know.



What on earth are you on about? Maybe you can get your mom to help you navigate the site while she's spoon feeding you your dinner. [i]"Open up, here comes the airplane! Brrrrrrrrrrrrrrrroooom."[/b] Good boy.

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Old 04-21-2003, 12:19 PM   #26
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Default Re: Why don't motorcycle journals present hard data?

Because most subscribers aren't data junkies and certain timings, braking, skid pad and top speed in particular can cost lives.



As a junkie myself, I wish manufacturers would determine and publish corrected top speed and rear wheel dyno figures because my spreadsheet can use them to calculate aerodynamic drag coefficients. I can't seem to find anyone else who cares.



Oh well...
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Old 04-21-2003, 12:45 PM   #27
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Default Re: Why don't motorcycle journals present hard data?

I do like the Idea of a more consistent format.
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Old 04-21-2003, 12:58 PM   #28
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Default Re: Why don't motorcycle journals present hard data?

While what I describe is most applicable to a track setting, and clearly can be pushed closer to the bike's limits in a track setting, it is true of most street riding as well -- at least the way I ride. Hard trail-braking on the street is not highly recommended, but some, light trail braking is normal -- even on a cruiser. Almost everybody I know does accelerate out of the corners.



The ability to use trail braking can be a real life saver, when you encounter an unexpected obstical in the road -- pretty tough to have to go with an either/or approach -- either try stop before you hit it, or swerve around it without slowing. The ability to do both can get you our of many jams. Of course, if you were already trail braking close to the limit, ya got nothing left.



My point was that even on the street, even riding a cruiser or touring bike, you seldom are cornering in a totally neutral mode: you are usually also using a little brake (or engine braking) or are also on the gas.



Especially on a track, cornering lines are a compromise -- the highest cornering speed would be acheived by doing all your braking early, while nearly upright, taking the largest possible radius for the turn, and not giving much throttle until you are one again nearly upright. This, however, also "wastes" a whole bunch of the straight.



What I was taught (for cars, many years ago) was to adapt the riding style for each corner to where you are on the track -- linked corners, or those with only short straights connecting then are taken with light trail braking, with an apex at close to the midpoint of the turn with gentle throttle out of the turn. If the turn is at the end of a real straight, you use heavier trail braking and an early apex, to effectively extend the straight as much as possible. Conversely, for a corner leading into a straight, you would brake early and use a late apex, getting on the gas hard as early as possible.



I believe that most 125 and 250 racers also use the same approach I describe -- the difference is in the proportion of available traction being used for acceleration/deceleration vs cornering. As a result, their lines are much closer to the classic, while some Superbike or MotoGP riders almost square off the corners, while coming to a much slower midcorner speed. For these very powerful bikes, this has the advantage of leaving most acceleration with the bike more nearly upright, on the fattest part of the contact patch (also has the advantage of being less wheelie limited).



The best riders are able to use a variety of styles as is required to pass or to adapt to the tires going off. That is where Rossi is so brilliant. Sometimes he can look like he is still on a 125, and other times like he is flattracking.



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Old 04-21-2003, 01:54 PM   #29
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Default Reliability Data?

Now your talking. Consumer Reports pays for itself a thousand times over (well, maybe a few hundred times over) when they publish data on the reliability of various models of cars. Short of searching the owners groups yourself, there is no similar collection of reliability data for bikes or listing of common problems. Does the average rider not do enough miles to ever find problems? Such a source of data would have saved me a lot of time spent researching various models of bike prior to my last purchase.
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Old 04-21-2003, 01:57 PM   #30
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Default Re: Why don't motorcycle journals present hard data?

I think it is an interesting topic and I was just thinking about it. I have been trying to pick my next bike and I like the Sprint RS but I cannot find any numbers for it. I found only one test that had it at 117 in the quarter, which sounds way slow considering how fast everyone says it is.



I really don't accept all the bull about rider weight/elevation/temperature/barometric pressure/rider temperament- I read these reviews to get opinions AND NUMBERS! Other magazines do it. The numbers appear in the magazines. Really- what gives???
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