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-   -   Are modern sportbikes engineered too close to the edge? (http://www.motorcycle.com/forum/godzilla/2818-modern-sportbikes-engineered-too-close-edge.html)

Pinkslip 06-01-2005 03:49 PM

Re: Are modern sportbikes engineered too close to the edge?
 
With the exception of Kawi's struggle to rebuild its rep for poor build quality, I've never been terribly concerned with the reliability of any Japanese sport bike. In the same breath, though, I would like to note that I would never expect a CBR, GSXR, YZF or anything of the like to last as long as a BMW motorcycle.



Race bikes are meant to handle all the extremes of racing.... for one season. Next year, there will be a fresh, new, improved bike in pit lane.



The fact that the cracked frame of the GSXR made such a big stink speaks volumes for the general structural integrity of those frames. If the bikes were built that poorly (like the frames on the old TL1000's) we would probably have seen more signs of it by now... or we will be very shortly. I doubt the crap frames of the TL's were so... crappy... to save weight- that bike is a pig.



In the end, unless every 201st Gixxer is cracking a frame, this isn't going to keep anyone from buying one.

brax4444 06-01-2005 03:50 PM

Re: Hear hear.
 
Was this from experience perhaps?

BMW4VWW 06-01-2005 03:53 PM

Re: Are modern sportbikes engineered too close to the edge?
 
My 15 year old BMW air head has 128,000+ miles on it, I ride like Batman (or would that be Robin?) and it still will blow the doors off of any car at an intersection. It still handles well, gets reasonable gas mileage, and is a piece of cake to maintain. I often wonder how many new fastest bikes of the week will still be around after that much time, abuse. VWW

Fenton 06-01-2005 03:54 PM

Re: Are modern sportbikes engineered too close to the edge?
 
Any advancement in frame, engine, brake and suspension is a wonderful blessing on our sport. The trickle down affect from racing is a much easier jump (cost wise) for motorcycles than other motor sports. You won't find the latest F1 engine and brakes in the new $26k Mustang any time soon.

Having the access to and exploiting the technology becomes the largest feat. I may find the frame flex difference between the R1 & the CBR interesting, however, I can't detect flex in a 883 Hugger. I could go buy a '97 YZF750 and never know it wasn't the new GSXR750.

Calling last years supersport a sled, when pitted against the "new" one, makes great copy but really doesn't apply to 95% of the people who buy them.

I have been turned into a spectator of motorcycle improvements since about the '88 ZX10. That doesn't include the sneaky leaker.

jungkvist 06-01-2005 04:05 PM

So far so good!
 
Yes, the new bikes are too close to the edge. As a matter of fact, I think that they are beyond the edge - way out past the reaches of Stupidity City. So, I canÂ’t imagine that there wouldnÂ’t be the occasional component-failure. Putting all the blame on the manufactures, when all theyÂ’ve done is build the exquisite machines that we keep demanding, is absurd!



The Japanese have done an amazing job engineering and building bikes that cater to the U.S. market. ItÂ’s not their fault were crazy!


dsouthard 06-01-2005 04:12 PM

Re: Great topic!
 
I agree with a lot of what you said, and yet....
<ul>[*]Does that high-reving I4 with tall gearing really
have more roll-on power when driven at legal speeds?[*] Can you really panic stop faster and safer without ABS?[*] Is "monkey humping a football" really the best posture for surveying the traffic?[*] Given that race bikes often get new fluids, fork service, plugs, etc, etc after every race, how much "longevity" is designed into the components for use with
a more mainstream maintenance schedule?[/list]There's no question that the current sport bikes are amazing
feats of engineering. But they were engineered for the track, not the street. I think a design targeted as the optimal solution for the latter environment would look a little less like a gixer and a little more like a CityX with ABS.



But modern race replica sportbikes are still way cool.


jungkvist 06-01-2005 04:41 PM

I want an SV Hurricane?
 
It probably would be the perfect-blend of high-tech and reliablity, but here's my idea of the "perfect" bike...



In the latest issue of Walneck's (on page B-4) there's a bike that they're calling a 1972 Triumph "Hurritwin" w/tracy bodywork. It's a conglomeration, but it's gotta be the most beautiful bike I've ever seen. (you guys should really check-it-out). I want an SV, dressed-out to look like that bike - with a top-of-the-line suspension and a small fairing.




Fenton 06-01-2005 04:43 PM

Re: Are modern sportbikes engineered too close to the edge?
 
There's that '04 R1150R abs, heated grip, 1500 mile bike at my dealer talking to me again. Maybe a Gobert tatoo will keep me away from those weenie BMWs.

dylanmo 06-01-2005 05:30 PM

Re: Are modern sportbikes engineered too close to the edge?
 
Everyone chip in and buy MO one of these. Put 100,000 miles of bad roads on the bike in a week, and see what's left. Manufacturers let magazines do that with new bikes, right? So, no problem.

Vlad 06-01-2005 05:56 PM

Too close to the edge?
 
The comments have engaged my relatively primitive metalurgical skills. I would like to point out that a frame's ability to survive a race, or a dozen races, is no indicator of how it will handle the stresses of 20 or 30 thousand miles. Aluminum is very light for its strength, but it is a brittle metal that is prone to stress cracking when subject to vibration over long time periods. Steel, on the other hand, is not prone to that kind of failure since it is more ductile. Aluminum frames can't be designed to handle the kind of flex that can be engineered into a steel frame, at least to my knowledge.



I know that reputable sources who are familiar with Ducati frames have said that the male slider fork assemblies that the boys at Ducati are so fond of have less flex. Therefore the frame needs more. I also know that Ducati's engineers design the amount of flex in the frame.



Steel trellis frames are essentially built by hand and are expensive. Aluminum frames are cheaper and retain the same lightness and strength of trellis frames. A steel frame can't be as strong and light as an aluminum frame without going to a trellis type construction. Which is more bucks.



Are we reaching the point that the aluminum frames have pushed the envelope too far? We won't know unless people start riding these bikes for thousands of miles. It does worry me that mighty Honda has had problems with the (aluminum) frames on the Gold Wings.



Engineering is an art that, by its nature, pushes the edge. The old joke about bridge design is "keep making it lighter until it falls down, then back off a notch." During the 50s there was an over engineered airliner which had the minor problem of losing a wing at a certain point in its life due to vibration cracking. It took a while to figure out the problem since it was hard to do an extensive analysis on metal that had failed, then fallen 20,000 feet, before it could be examined.



I know there's a lot of knowledge out there in the MOron community. I could be full of it, but I certainly wouldn't want to plan doing much touring on a bike whose frame was designed without consideration for vibrational stresses. You simply can't escape vibration on a motorcycle with an internal combustion engine.



Maybe these failures are only insufficient engineering. Maybe they are due to some special stress the bike received before its sale. Or maybe the engineers are chasing "light" a little too hard.



Francis


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