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Bar-End Weight FAQs
Q. So why ever buy these, especially since there are pretty aluminum ones for cheaper?
Q. Why not for aluminum handlebars?
Q. How do bar-end weights change the resonant frequency?
Q. Will all that weight on the bar ends slow down the responsiveness of my bike?
Q. Can't I just tough it out and save money?
Q. So why ever buy these, especially since there are pretty aluminum ones for cheaper?
A. In a word, MASS. Almost all bar-end weights on the market are designed as sliders or decorations. Many kinds of bikes, especially modern inline fours, don't vibrate much in the handlebars. For bikes where vibration isn't bad enough to cause trouble with your hands, then decorating your bar-ends is something you can afford to do.
These weights are designed for the paint shakers- the twins and singles of every vintage, that make your hands go numb, or hurt, with long-distance riding. The extra mass is necessary to reduce the vibrations of these sorts of bikes. You can read how, on another FAQ.
A. Depends on which kind they are: |
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Hollow Tube Style weights (7/8" & 1")!!!MANIC Salamander bar-end weights are mounted with a direct metal-to-metal fit. No special threaded hole or other attachment point is required, just a hollow tube. Most weights on the market are rubber-mounted. Rubber-mounting is an inexpensive way to fit a large variety of handlebar sizes, but it compromises the resonant frequency reduction. I have taken great care to design a solid-mount that makes no compromise. These are the 300-pound gorilla of bar-end weights, and if they don't solve your problem, you should be looking for cracked welds, broken motor mounts, bent crankshafts, or failing engine bearings, not new accessories. |
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Bolt-on Style weights (6 mm & 8 mm)Bolt-on weights are designed for handlebars manufactured with a threaded hole in the tip, to attach endcaps or weights. Typically, they just bolt on in the same place where the factory one did. for some models, we carry General Purpose bolt-on kits, which have longer stainless screws you can cut down, and flatwashers to space the weight properly from bikes that have the right hole in the bars, but are not on our specific applications list. That is the most work you will have to do to install a bolt-on kit. |
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A. If you are the sort who loves riding vintage bikes far,
If you feel unnatural when you don't ride your Enduro or Dual sport TO the trail,
If you just can't get enough of your Yamaha XS 650, Harley Sportster, or Triumph, etc. and keep riding it across the continent,
If your hands feel bad from all the shaking,
These are EXACTLY what you've been waiting for!
Besides, they look super trick, and the chrome is sooooooo shiny!
There are a lot of newer machines that benefit from them, too. They are popular on Moto Guzzis, Harleys, Suzuki Bandit 1200s, and large dual sports, to name a few.
A. See the Bar-End Weight Compatibility list for a running list of applications. There are tons of others besides these, we just don't know what they are yet. Some generalizations: |
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Hollow Tube Style weights (7/8" & 1")Any bike with 7/8" or 1" steel handlebars, with 2.5" clear inside the ends of the tube. You need to see if your handlebar is the 7/8" or 1" size. All Japanese bikes up to the time in the early 80's when they started experimenting with cast and forged aluminum handlebars, will fit the 7/8" size. There are plenty of Japanese bikes since then that also work, you just need to verify that they have hollow steel handlebars. Almost all Japanese cruisers except Yamahas take the hollow-tube weights, in 7/8" or 1". Since about the 2003 model year, it has been all 1". But older models, like Rebel, Vulcan, Eliminator, may still be sold with 7/8" bars. Japanese sportbikes are more and more switching to clip-ons. They may fit the hollow-tube style, but they are probably made of aluminum, in which case we have not yet developed a fitment for them. All Moto-Guzzis I have tried fit the 7/8" size, too, though newer cruisers may have switched to 1". On Harleys, the ones with air suspension components in the handlebars are not compatible, and some models have a stub sticking out for the throttle to pivot on, which is also not compatible. Otherwise, they all take the 1'' size. Buells all take the 7/8" size, and it protects the bike a lot better in a get-off than the silly plastic nubs. Triumph's classic models (from the old Triumph) fit the 7/8" size. We do not have a unit that fits new Triumphs at this time. All custom cruisers with steel handlebars will fit the 1" size. Norton's, and Urals fit the 7/8" size. Most newer (2004 on) Yamahas do not fit our current offerings. Stay tuned, we're working on it. More and more often, OEM's supply Cruisers with fancy plastic and metal handgrips that wrap around the end of the bars. These are hard to install weights on, and we recommend purchasing normal, easy-to-grab rubber grips, so you can just slice the end off and be done with it. There is more to say, but those are the easiest generalizations. For more, go to the compatibility list. Here is how to tell if the hollow-tube style of weight fits your bike: To tell if the bars are steel, expose the end of the bar, and feel inside. The inside should feel gritty, probably reddish, and there should be a raised seam that goes all the way in, past where you can feel. If you can't feel that seam, the bar is probably aluminum. Also, a magnet will stick to any steel bar, but not aluminum. A magnet is not a good test for Stainless Steel, because it will stick or not depending on the alloy.
As for 7/8" or 1", that refers to the Outside Diameter of the bars- how wide the circle of the tube is on the outside. Put a ruler to the end of the bar, and measure how wide the circle is. You should also check for any obstructions in the bars. The inside of the bars must be clear for 2 3/8" to be safe. Some bars have a nut welded inside, to attach weights with a bolt. Others have a stub for the outside of the throttle to pivot on. The weights I am offering first, will not work on these bars. You only need to check the throttle side. It it's clear, the other side will be, too. |
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Bolt-on Style weights (8 mm Kawasaki)Many Kawasakis from the '80's on take the 8mm Kawasaki bolt-on model. Any bike with a female 8mm-1.25 hole in the end of the handlebars, that protrudes from the tip of the bar a little, like this bike: Bolt-on Style weights (8 mm BMW)The 8 mm BMW bolt-on weight was designed for BMW oilhead or K-bikes with factory bar end weights mounted on posts that stick out past the grips, as shown here. Bolt-on Style weights (6 mm Yamaha)The 6 mm Yamaha bolt-on weight was designed for the Yamaha FJR 1300. Bolt-on Style weights (6 mm Honda)The 6 mm Honda bolt-on weight was designed for any Honda with stock bars that came from the factory with bolt-on endcaps or weights. This is the only fitment in our line that utilizes rubber damping. The reason is user-friendliness. The threads in the Honda bars are integral with a factory rubber damper system, and we can't really get around it in a bolt-on fitment. |
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A. If you have a bike that has another size of handlebar, and can make it to Minneapolis, MN, I may be interested in working with you to make a product to fit. That normally comes under custom work, but for the more popular applications, I would cut you a special deal, since I want the opportunity to fit the bike anyway.
PLEASE let me know if you would like these weights, but have an application they will not fit. I will come out with new flavors in the order of these requests.
Q.Why not for aluminum handlebars?
A. Fatigue resistance of the metal.
Steel has nearly infinite fatigue resistance within its elastic limits (meaning as long as the vibration never bends it so hard it can't spring back.) We made our weights as heavy as we could, while sticking out minimally, looking good, and above all, not overstressing any other part of the bike. We are confident that steel bars can handle the added stress.
Aluminum is another story. Aluminum has a finite fatigue resistance. This means that persistent vibration anywhere near the elastic limits, will eventually cause the piece to crack in two at the place with the most severe flexing due to the vibration. For this reason, Aluminum structures that are subject to vibration, or other repetitive dynamic loads, must be dramatically overbuilt, to keep the flexing way down.
I am sure the OEM's have done the extensive testing and sophisticated modeling to determine that Aluminum handlebars will not crack off in normal use. However, our first line of weights is pretty extreme. In some applications, you can feel that the tips of the bars vibrate less than the instrument pods. This means that the handlebars may be flexing MORE in some places, than they do without weights, just to take the vibration away from your hands. Thus the risk of metal fatigue goes up. It MAY be safe on Aluminum, anyway. But we have not done the testing, modeling, or calculations to determine whether it is, or not.
If we hear enough popular demand, we may make more conservative weights for Aluminum applications. Please write in to weights@manicsalamander.com.
AAAAAAyyyyy!!!
Bar-end weight theory:
As your motorcycle runs, the handlebars form a resonant mechanical system. That is, the bars tend to shake at a certain frequency. If this frequency is any component of the characteristic frequency spectrum of your motorcycle, then the bars start to flap away, bothering your hands.
More technical:
As your motorcycle runs, the handlebars form a resonant mechanical system. That is, the bars tend to shake at certain frequencies, in certain ways. The lowest frequency, or fundamental, is a motion you could call, "flapping." This is where the center of the bars, between the clamps, is motionless, and the tips of the bars are vibrating most. This is typically the strongest mode of vibration, and the first one you should attack. If this frequency is any component of the characteristic frequency spectrum of your motorcycle, then the bars start to flap away, bothering your hands.
There are three ways to solve the problem.
- Stop the vibration. Many aspects of motorcycle design can come into
play to check vibration at the factory. Details of crankshaft design,
firing order and angle, mounting location, and counterbalancers can
be used in concert to make for smooth running. If the engineers who
designed your bike were skillful and careful about these factors, as
they affect vibration, you can stop reading now- you don't need this
product.
- Dampen the vibration. From an engineering standpoint, dampening means
eliminating the resonant frequency of the handlebars. The proper way
to do this is with a precisely designed flexible attachment between
the vibrating part and a solidly mounted part, in other words, a shock
absorber. The flexible attachment must be tuned to exactly oppose the
specific frequencies of resonance, so vibration put into the bars will
not be allowed to build up in them and hurt your hands.
Unfortunately, there is no proper way to dampen the handlebar motion, without a mechanical linkage from the outside of the bars to the frame of the bike, other than the bars. There are products out there which purport to dampen handlebar motion, but they can't technically "dampen" the fundamental frequency, since there is no linkage between the bar ends and the frame.
That is not to say they don't "work." I haven't tried them, but I know many who are quite satisfied with them. Why, if they aren't dampening the bars from flapping? The higher-order harmonics of the resonant frequencies should be effectively reduced by, say, inserting a combination of weight and viscoelastic material into the bars. Due to the physics of the situation, the higher the vibrational frequency, the less weight is required to disrupt the motion, and the less solid the mounting point of the dampening system needs to be. So having a heavy elastomer all the way through the bars would be great for the higher harmonics, with the internal motion of the elastomer discouraging the formation of standing waves in the bars. But that lowest resonant frequency, the flapping motion, is typically the strongest. For that motion, all that elastomeric stuff in the bars is only as good as its mass. In other words, it operates just like plain weights- it lowers the resonant frequency, and discourages the tips of the bars from changing speed quickly.
This brings us to the last means of vibration control.
- You could change the resonant frequency.
When operating in this mode, the closer the weight is to the tips of the bars, the more effective it is. Solutions that involve equal mass throughout the length of the bars, have only a fraction of their mass working for the cause. The rest is dead weight. As a rule of thumb, any mass between the first two curves of the bar from center, is dead weight, and any mass at the tips of the bars is fully effective.
That's why our bar-ends are designed to maximize weight just outboard of the bars. They are 12.75 oz. per side, and every ounce hits home.
Q. How do bar-end weights change the resonant
frequency and reduce vibration?
A. Resonant frequency is the frequency at which an object
"rings" if it is moved. When you hit a tube with a hammer, and
listen at the end of the tube, you are hearing the audible portion of
its resonant frequency spectrum. The "fundamental" is the lowest
note. In handlebars, this is the frequency made by the bars "flapping."
By flapping I mean that the bar clamps stay put, while the tips move most.
This fundamental frequency is typically the strongest frequency, thus
the first one to attack.
Weights on the tips of the bars reduce vibration by moving the resonant frequency lower, away from the frequencies generated by the engine. This happens for the same reason that a heavier guitar string sounds lower, under the same tension, than a lighter one.
Because the effectiveness of a weight in reducing vibration this way reduces to zero as the weight approaches the bar clamp, I was careful to keep as much weight outboard of the bar ends as possible. All the weight is concentrated where it is most effective- right near the bar-ends. All the weight is within 2.5" of the bar ends. There's no dead weight as with solutions that go all the way through the bars. By moving the resonance lower, it typically moves further from the frequency of the engine, which reduces the build-up of vibration in the bars dramatically.
The other way to look at it is in terms of inertia. By solidly mounting the weights to the ends of the bars, the bar-ends gain a great deal of inertia, which means that they are much more reluctant to change speed. Since the flapping motion involves the bar ends accelerating this way and that in rapid succession, any weight on the ends reduces this motion.
When you are trying to contain vibration by changing the resonant frequency, solid-mounting is the way to go. Any flexibility to the mounting muddies the effect of the extra weight, hurting the cause.
Q. Will all that weight on the bar ends slow down the responsiveness of my bike?
A. Theoretically, yes, a little. However, people typically report that responsiveness is not affected by measures like these. I have even heard of people pouring molten lead into their bars, filling them to the brim, (a few times the mass of our bar-end weights) and saying their handling was unchanged.
Why wouldn't you notice a slow-down in turn initiation? A way to understand this is with the concept of resonance, and its effect on the ability of the bar ends to change speed, discussed above. The fundamental frequency of the engine (67 Hz, for a single, operating at 4000 RPM) is at least 130x the frequency of a rider's steering input. (0.25 - 0.5 Hz.) That means that a weight which is sufficient to seriously discourage the engine resonating with or flapping the bars, is inconsequential to the much lower frequency involved in steering the motorcycle.
Q. Can't I just tough it out and save money?
A. Maybe. If you are lucky, you have very good circulation, well-routed nerves, strong wrists and hands, and you can tough it out. But long days in the saddle can wear you down, and in the long run, it's best to take care of yourself. Depending on you and the bike, vibrations can get seriously harmful to your health. Vibrating bars can worsen carpal tunnel syndrome and arthritis, aggravate circulatory problems, cause numb or tingling hands, etc. If this happens to you, take it seriously. Most of these problems get aggravated more, the more they get aggravated. Give your wrists a break!
See our article about Hand Trouble for more information.
