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Discussion Starter · #1 ·
Hey guys. I'm new here. I have a 2005 zx-6r completely stock with exception of my flushmount signals.

I've only been riding for a few years, and I'm curious. What are the pros/cons of magnesium wheels or lighter wheels in general? I've searched the forums a little and found minimal information, and I have had trouble on google as well. I've read that they are prone to cracking, and that's about all?
 

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Less unsprung weight spells numerous advantages, most of them can only be truly exploited on the track though. Less drain on the drivetrain means more horsepower to the actual contact patch, less lost in moving the actual wheel, also due to the weight loss there should be an increase in turn in, lending to a feeling of easier transitions into and out of corners. On the street theres an improvement, on the track a more exploitable one. Lighter weight whether it taken from the wheels, or your beerbelly, will increase tire life, gas mileage, decrease engine wear/strain, ect.. Lighter weight is awesome! Observe Stoner, literally living proof. Mag wheels definitely increase the bling factor on the street! Although I have heard of mag's having longevity issues...
 

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This bike is practically made of magnesium!



Not to destroy the thread but this bike is awesome! Saw it when I was looking at Mg products. Please continue on with explanations about MG's benefits and drawbacks.
 

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Discussion Starter · #6 ·
Thanks old green machine, and others. That was the kind of explanation I was in search of. It might be a little more frugal to shed some pounds off of my frame, instead of my bikes - heheh
 

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Reducing rotational weight is an interesting concept. The faster you're going the more weight you're technically saving. Basically rotating mass will cause the bike to travel in a straight line. By reducing rotating mass you're going to make it substantially easier to turn at spee... you know what, someone far better then me has a writeup on this.

ab420 said:
One of the greatest performance modifications you can do to your bike, is to put on lighter wheels! I know, you see that these wheels weigh like 10 pounds less than stock, so you're thinking, 10 pounds isn't gonna justify paying all that money for nice light rims. But the question is not how much weight are you saving, it's where is the weight you're saving?

Lighter wheels will make a major difference in the handling of your bike. They will also greatly improve the acceleration and deceleration “braking” of your bike for the following reasons.

Non-Rotational Weight: One ounce reduced from the wheels total weight, is equal to 4 ounces taken off another part of the bike. Magnesium wheels will normally weigh at least 10 pounds less than your stock aluminum wheels. This is equal to 40 pounds of weight reduction on the bike.

Rotational Weight: This is the weight reduction on the outer rim of the wheel and this is where the weight reduction makes a HUGE difference. At 100mph, each ounce of weight reduced here, is like having 25 pounds of weight taken off the bike!

This is real weight that must be turned, accelerated, and stopped, and likewise, it will improve turning, acceleration, and stopping.

At any speed the reduction is relative to the velocity of the bike. As you increase your speed the weight savings will increase exponentially.
ab420 said:
No, I'm saying that 10lb. lighter rims at 100mph, is the equivalent of saving 250 lbs. of non-rotational weight off the bike. This sounds insane, because at certain speeds, the amount of weight you would "virtually save," can even be more than the bike weighs. How is this possible? Remember, we are not talking about weight really, we are talking about the performance you can achieve from different weights. So, say you lost 20 lbs of rotational weight, thats like losing 500lbs off the bike. Now if your bike only weighs 450, how does that work? Obviously, this will not make your bike weigh nothing, it just means that the performance you gain, would be similar to the amount of performance gained by reducing the weight by 500 lbs, even though the bike doesn't have 500 lbs to lose anyways!

Hope that helps.
 

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Thanks old green machine, and others. That was the kind of explanation I was in search of. It might be a little more frugal to shed some pounds off of my frame, instead of my bikes - heheh
I remember when I was a little kid my dad and I used to go down to the track and it was loads, but a memory that still stands out in my mind was this "overweight" gentleman who was bragging about his titanium exhaust for his Corvette, I can't remember the exact numbers but I do remember that he could have lost that weight off his "tire" and saved the thousands he spent on his "Ti" system. I knew that was bull even when I was a kid. Get out and ride... a bicycle!

I'm not sure I understand the logic behind the explanation of the wheel weight loss at speed, I would say that the benefits begin to taper off the more weight you lose, but I'm no race engineer either. All I know is what I've read (which is quite a substantial amount) and know that Mg wheels are a wise investment if handling is an important factor to you. I also know that something that sounds too good to be true is probably just that. Losing 500 lbs. off a 450 lb. bike? So at 100MPH that would mean your riding a bike that weighs -50lbs and has 150 or so HP? Even if it's obvious that the bike weighs the same, your not going to get that kind of performance just by slicing wheel weight. IMHO sounds too good to me, but like I said before, I'm live in suburbia, not the racetrack, but in my defense, I do have a brain, and that sounds like a Marchensini rep trying to make a quota to me.



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Ehh, I think it's excessive as well, but remember that a spinning object basically generates it's own momentum, the heavier it is the tougher it is to alter the momentum.

So a lighter wheel will increase your turn in, and basically make it much easier to ride around the corners. I suspect the numbers he was using were basically made up. But the point holds firm. Lighter wheels will affect handling in a huge way.
 

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Ehh, I think it's excessive as well, but remember that a spinning object basically generates it's own momentum, the heavier it is the tougher it is to alter the momentum.

So a lighter wheel will increase your turn in, and basically make it much easier to ride around the corners. I suspect the numbers he was using were basically made up. But the point holds firm. Lighter wheels will affect handling in a huge way.
I concur!
 

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Ehh, I think it's excessive as well, but remember that a spinning object basically generates it's own momentum, the heavier it is the tougher it is to alter the momentum.

So a lighter wheel will increase your turn in, and basically make it much easier to ride around the corners. I suspect the numbers he was using were basically made up. But the point holds firm. Lighter wheels will affect handling in a huge way.
Yeah I think there's a confusion here talking weight when it should be reciprocal mass or something. Can't remember the exact physics but it's something along the lines of momentum x weight therefore less weight saves more reciprocal mass and reduces gyroscopic forces as speed increases.

As others have said the lighter wheels will improve handling and reduce the physical rider input required to shift the bike from side to side. On the road the difference will be noticable at speed but the true benefits will only really be appreciated on the track. The downside is that they may not stand up to excessive use on regular bumpy roads. For an idea of what can happen look for a video of Robert Dunlop at the Isle of Man a few years ago when his rear wheel collapsed :scared . Others have had similar issues with wheels cracking on street circuits. They sure look good though!
 

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All Heil Joey Dunlop! Anyways, I personally prefer a heavier wheel for serious street riding. I think if I went to a track and rode all day I'd appreciate a pair of mags but on the street heavier wheels to me mean more control, it's more work and requires more strength and energy but it also allows me to modulate the bike with more control. Sure it's exhausting but it's also reassuring. Just my 2 cents. I've rode a small handful of bikes and have noticed on twisty roads I prefer heavier wheels.

Please note: this is only in the case of short sprints on the roads in my area where fast corners most definitely mean suicide (gravel, potholes, tractors, animals, ect.)! I'll move to the track someday!
 
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