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Blake
| | Posted on Sunday, December 16, 2001 - 06:03 am: | 
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Interesting topic from GDB.  |
Sportyeric
| | Posted on Friday, December 14, 2001 - 02:33 am: |
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Oh No. Jocklandjohn has revealed the Sportster's secret. But don't call it a tarmac roller any more please. |
Timmy2shoes
| | Posted on Friday, December 14, 2001 - 08:58 am: |
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Aaron,
no, not an engineer... A software developer, I am...
I am only drawing from my experiences, (i used to have a Rokon) and as I stated before (maybe on another board?) It would cut off power to the front drive when you turned the handlebars to a certain point. Before you reached that point though, the bike would try to "pull the front end" out from under you. felt like a near highside, everytime you encountered that situation. Of course, my Rokon was powered by a diveshaft that ran the length of the bike, with a chain drive powering the front wheel... it also had tractor tires, and no suspension. Not the best handling bike to begin with
I have no basis for argument other than my personal experience with 2wd bikes. (albeit limited to one perticular bike) I also think that if 2wd were desireable, wouldn't more manufacturers have tried to develop something before? I would consider myself a purist, who embraces technology, but technology, for technology's sake, is something I don't want (at least on my motorcycle. If it makes the bike better, then hellz yeah, you'll get my money, but on this 2wd sportbike.. my verdict wil still be out.
Any insight onto the benefits of such a system? Particularly in cornering? (at speed even). I could see where **possibly** corner exits (per your SCCA reference) might be improved, via less rear wheelspin.... but.... hmmm.... I dunno...
Tim |
Aaron
| | Posted on Friday, December 14, 2001 - 10:02 am: |
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Well, I've never roadraced a motorcycle, much less on a 160hp Superbike, but if it's anything like racing a 600hp Trans-Am car, yes, wheelspin exiting corners is a major issue, you really have to modulate the throttle to keep it planted, particularly on tighter turns. It's really a big issue on a street course, but even on relatively open road courses, it's an issue. You always want to get on the throttle earlier and harder, and available traction often limits you. Good rear suspension design (proper anti-squat) really helps.
I guess we'll see how much or little it helps a bike. Keep in mind though that even 1% improvements are huge. In racing, you typically get a 1% improvement by adding up ten .1% improvements, and each of those takes a lot of work and development. |
Jasonl
| | Posted on Friday, December 14, 2001 - 11:56 am: |
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Let me ask this:
If you had a two wheele cycle that could accelerate like a normal cycle would you pull wheelies? I don't think so. Most of a wheelie is an effort to accelerate away from a curve. Once you are at a certain wheelie point you will not accelerate any faster. But if you have 2 wheels putting power down it is possible to put more power to the pavement and accelerate faster without the need to wheelie since you have the traction you need without all the antics.
Also the rider in the article said the R1 was a handful to ride at the limit of adhesion. He states that a rider of an R1 has to balance wheelspin out of a corner with acceleration. He then goes on to state that since the rear doesn't "spin up" as readily he can accelerate harder out of a turn.
To me, that shows the system is worthwhile. It is crude right now but I'm sure it could be improved and lightened.
This is the future folks. |
S320002
| | Posted on Saturday, December 15, 2001 - 01:21 am: |
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BHRalf,
Don't forget about the third gyro, the engine flywheel.
Blake,
Countersteering in a corner will tighten the line.
If you prefer a more expert opinion ask Keith Code, he teaches it in his classes. If physics helps, consider what countersteering while leaned over does to the wheelbase.
Magazine test riders; the problem with many of these guys is that they spend too damn much time on the race track. Its like a Quantum Physics expert trying to teach Algebra. They've spent so much time way out on the edge of the curve they forget what the real world is like. After all if it doesn't have 180 hp and wouldn't scare the crap out of Ben Bostrom it couldn't be any fun on the street, right?
Greg |
Jim_Sb
| | Posted on Friday, December 14, 2001 - 01:17 pm: |
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Blake: Movable air foils are certainly an option. I would think you'd want to create additional downforce to keep the wheels planted and to help counteract the centrifugal (or as you say, centripetal) force of a high speed turn. Whether used to create lift or additional downforce, they ~will~ create additional drag. One doesn't come without the other...
2 wheel drive could be viable. With more weight on the front wheel and the front wheel pulling through the turn? Hmm... They told the Wright brothers they were nuts too...
Jim in Santa Barbara |
Jima4media
| | Posted on Friday, December 14, 2001 - 02:41 pm: |
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Mikej,
That was my feeling on the 2WD subject too. Until someone wins a motorcycling championship with one of these things, it is interesting, but not significant.
Jim
X-2.5 |
Jasonl
| | Posted on Friday, December 14, 2001 - 03:40 pm: |
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How many of you are driving AWD cars now? Wouldn't it stand to reason that if you couldn't experience the difference between an AWD car and a 2Wd car that you may underestimate the differences between a reg cycle and one that is 2Wd?
Besides that how many of you are reserving judgement on a FireBlast until you ride one? How is this cycle/situation any different? |
Doctorgorpon
| | Posted on Friday, December 14, 2001 - 04:08 pm: |
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Regarding two wheel drive.
There have been moments when I've had my bike on the track where I have started to have the front end wash out on me, and I have thought to myself afterwards if only I had drive from the front wheel I could drive the bike out of those situations. When the front wheel comes lose at extreme angles maybe power on the wheel would allow it to power through the lean as opposed to slipping. Other than this sort of extreme application I don't see any day to day benefit for TWD. |
Blake
| | Posted on Friday, December 14, 2001 - 05:13 pm: |
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Jim: Yeah, downforce relative to the tarmac, but when leaned over at 60 degrees from vertical it'd be more of a side force relative to the bike right? Depends on your frame of reference. Downforce on the exit would be a good idea too, something to help keep the front end planted and the rear tire in good grip. |
Blake
| | Posted on Friday, December 14, 2001 - 05:21 pm: |
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I've heard somewhere that at 180 to 200 HP GP bikes are pushing the limits of grip, so any more power is simply not usable. Seems like some downforce mechanism would be real useful with the new engines coming out. Of course the wider powerbands of higher HP engines will always be an advantage. Tuning a 200 HP engine down to 180 HP but increasing it's low end power will go a long way to winning a race. |
Jim_Sb
| | Posted on Friday, December 14, 2001 - 05:45 pm: |
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Blake: Regarding Downforce, an airfoil does not care in which direction it's resultant force is applied. The "V" Tailed Beech Bonanza (around for more than 50 years now) is proof positive. We also know that the resultant force from an airfoil will be applied perpendicular to the placement of the airfoil.
Airfoils could be attached to a bike that would force down both the front and rear tires. They could be fixed such that the force is always parallel to the bikes vertical axis, such that in a straight-away they push the bike straight down while in a curve the push down on the bike's vertical axis into the tarmac.
They would cause additional drag of course. They would need to be mounted high enough up on the bike (or centrally located such as on the front fender) so as not to limit lean angles.
I can't believe this hasn't been thought of and tried by someone. It seems very plausible to me...
Jim in Santa Barbara |
Sarodude
| | Posted on Friday, December 14, 2001 - 06:33 pm: |
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Jim-
As the bike's vertical axis leans over, your 'into the tarmax' downforce would also be working to push the bike sideways. Someone wanna figure out the net results?
All that aside, AERO DOWNFORCE IS A BAD THING FOR RACING. It's in the best interests of EVERYONE to keep bikes reatively pure rider / machine combos.
One of the many things gone wrong in 4 wheeled F1 world is braking distances which have shrunk beyond reason making passing difficult. Even in the day when I thought I'd NEVER own a street bike I watched bike racing 'cause it's infinitely more exciting that most high level auto road racing.
The other techincal challenge / blockage comes from 99% of motorports calling for 'no moveable aerodynamic devices' or some similar intent.
My limited aero knowledge states that the best way to make downforce on a racebike is likely already happeneing. Think of the shape of a fairing if you look at an upright bike from above. Symmetrical airfoil. Now lean it over. The 'top' side is seeing the aero effects without some containing surface which would limit the amount of the Bernouli / Venturi (I get those two mixed up) thing. The 'bottom' side would be damned close to the ground - greater speed delta, lower pressure, downforce? If so, it would be DOWN (at least mostly) force, not DIAGONAL force...
-Saro |
Newfie_Buell
| | Posted on Sunday, December 16, 2001 - 07:55 pm: |
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I have found an interesting web site on a two wheel drive dirt bike.
Check it out.
http://home.mira.net/~iwd/2x2x2/index.html |
Bullitt
| | Posted on Monday, December 17, 2001 - 12:40 am: |
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There is an article in this month's Motorcycle Consumer News on this very subject, with a good (well, for me, that means non-engineer/aerodynamicist) description of how the various aero forces come into play. It was an eye opener for me, especially the part about front end lift and the weight transfer that takes place at speed - speeds that are not necessarily all that high. |
Blake
| | Posted on Sunday, November 16, 2003 - 11:53 pm: |
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Two quite years go by and...
http://www.gizmo.com.au/public/News/news.asp?articleid=2351
I wonder how much weight the system adds when implemented on a 100+rwhp sport bike. |
Koz5150
| | Posted on Monday, November 17, 2003 - 12:00 am: |
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Check it out. Pretty wild stuff
http://www.gizmo.com.au/public/News/news.asp?articleid=2351 |
Nevco1
| | Posted on Monday, November 17, 2003 - 05:40 pm: |
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Personally, I can't wait to take one for a test ride. The concept is awesome. I bet the engineering staff working on the project is as excited as can be with the product finally coming to fruition.
Can you imagine the effect that would have on a BattleTrax or SuperMotard course...Not to mention ice racing. Oh Lord...Please put me on the list for one now!!!
Can't wait to read the initial reports from the MC Press. Especially, since they aren't all that motivated by developments like linked and ABS brakes. |
Blake
| | Posted on Thursday, November 20, 2003 - 07:53 pm: |
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I'm not seeing how it would benefit Battle Trax. |
Nevco1
| | Posted on Friday, November 21, 2003 - 08:00 am: |
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On conventional street bikes it probably would not. I was only thinking that the additional front end control would benefit those that ran it on track prepped supermotard type bikes.
The supermotard guys I saw this summer were pushing so hard it seems logical. Don't recall their times, but they took B-Trax to a level where there was no competition. Was like putting you and your bike against Nicky Hayden and his factory ride on the track. Nolo Contendere! |
Blake
| | Posted on Friday, November 21, 2003 - 11:17 am: |
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Nicky Hayden could probably whup me even if his bike had flat tires and was firing on three cylinders, LOL. |
Spiderman
| | Posted on Friday, November 21, 2003 - 11:26 am: |
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I could see where it would. I don't know how effective the front wheel turns IE as well as the rear
BUT In Drag racing you want As much dead weight to the rear an above the tires for better traction.
NOW stay with me here,
If you are in BT where you are constantly transtioning from corner to corner loading up the front suspension. That is a lot of weight on the front wheel an with it actually driving the bike will pull a little bit better. It isn't gonna increase your times an astonishing rate but I can see it happening. Heck even the article said the 2 wheel drive R1 was pullin 5 sec better lap times than a single drive R1 ( I believe that was the time) |
Nevco1
| | Posted on Friday, November 21, 2003 - 12:36 pm: |
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Blake...Glad you saw the humor in the comparison.
Spidey, et al...was thinking of the chicane and circle sections for the supermotards. They were slippin' and a slidin' both ends in these maneuvers.
I had a better view than the rest of the field did as I was on the course playing flag boy at two events this year and watched them from the side lines at a third. They did not participate in the fourth event I watched this year.
I can tell you one thing for sure. No entrant on a street bike could possibly do that they were doing on a BattleTrax course, at least not any of the four I saw set up in Wisconsin this year.
Is also the reason why I feel strongly that BattleTrax is not a warranty voiding issue. Buell's are excellent street bikes for the event, but to generate any stress on them that could be considered race abuse is virtually impossible without wiping out. The course layouts are just that tight.
At the Hal's event, I got there early to help set up and Reg explained the process of how he reads a lot and sets up the courses. He had two folks with him that were BattleMasters-in-training and the discussions were free flowing. A few weeks later, I had the same privilege with Doug and Dave from Waterloo HD/BMC.
Bottom line is the courses are designed to keep things slow, safe and sane. The technical stuff like chicanes, circles and switchbacks are used to control speed and avoid hazardous conditions in the lot.
Apologize for getting long winded and slightly off subject. As Reg pointed out the key to winning BattleTrax events is smooth riding techniques that will allow you to gradually pick up the pace during the day. Considering, this I would think that the two wheel drive bikes would benefit from the additional traction and tracking abilities which could make the event even safer and more confidence inspiring.
Hey, what do I know. I am just a sucker for new technology and two wheel drive seems like a neat thing. |
Spiderman
| | Posted on Friday, November 21, 2003 - 12:49 pm: |
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Ummm nev that is basicaly what I said. But not as long winded 
Weight=Traction an if your front suspension is compressed weight is trransfered an the power transfers easily to that tire. Like the Subaru wheels that slip stuff. |
Nevco1
| | Posted on Friday, November 21, 2003 - 03:05 pm: |
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Sorry, not an engineer/mechanical type and still whining about the B-Trax issue. |
Spiderman
| | Posted on Friday, November 21, 2003 - 03:22 pm: |
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LOL Me too I love to void my uhhh i mean Run Battle Trax!!
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