How to Eliminate Handlebar Vibration
I filled my handlebars with rubber butyl sealer from a caulking tube/gun. The vibration went away, but be sure to completely fill the bars to eliminate moisture. Best way is to slip a clear piece of tubing over the caulk tip, then insert it into each bar end before filling. Make sure the tubing is at least half the length of the bars to ensure complete coverage.
A suggestion from another list (COG) is to fill the bars with birdshot, but the Concours has clip-ons so it would use a lot less shot. Filling the XS bars would probably be too heavy but a combination of James Ho's Caulking compound to reduce the space in the bars and then birdshot in the ends would work.
What follows is a thread from the XS11 mail list. It may be the most comprehensive discussion on handlebar vibration ever.
Dave Butler wrote:I can ride the bike for 2-3 hours with out the numb tingling coming on but my wife rides for 45 min and she starts to feel it and it gradually builds to pain mainly in the right arm, wrist. Im currently looking for a fix and toying with either or both of these options.
Anyone out there got a spare set of Gold Wing Handle bars, and setbacks/raisers they care to part with? Or a better option?
- handle bar raisers/setbacks
- Goldwing bars, this fix was once mentioned on this list.
JP Honeywell wrote:I got the Gold Wing bars and it helped with the weird wrist position that the buckhorn bars had but... they still vibrate. I want to try James Ho's Butyl rubber fix on my tech tips page. The vibration seemed particularly bad at 3,500 and another rpm (I don't recall at the moment). Made my fingers fall asleep from the buzziness.
Jeff Hall wrote:Has anybody tried weighted bar ends? I heard they are suppose to eliminate most of the vibration. Just a thought....
Michael Saar wrote:I used a set of bar ends and foam grips. No more buzz related finger sleepeezzz. Getting caught in a deluge in NC last week has however shrunk my gloves enough to make the fingers tingle after awhile tho'. I guess the leather will stretch back out.
John Higgins wrote:There are just a few ways to try to mitigate a vibration problem in general I think. You can try to dampen the vibration (rubber like material inside the bars?, lead bbs might be better energy eaters and would add beneficial mass). You can try to change the resonant frequency of the bars so that the bars do not respond to the external vibration at cruising speeds (stiffer bars will tend to cause the high amplitude vibration to shift to higher speeds, longer or weighted bars will tend to cause high amplitude vibration to shift to lower speeds), or you can try to isolate the bars or yourself from the vibration by positioning a soft--low frequency spring along the path of vibration (foam grips between your hands and the bars or something to isolate the bars from the rest of the bike at high frequencies--no ideas here). You might try some combination of treatments.If you put a really good engineer to work to try to solve your problem using modal analysis tools, he/she would probably spend as much time trying to figure an effective fix as you would by simple experimentation. The bike is a complex mechanical system and any one modification is likely to change several modes of vibration in the bike and give you an unintended result.
JP Honeywell wrote:You sound like you know what you're talking about so I'll bite the hook. Why would mass be beneficial? I'm thinking that unless you filled the bars from end to end with lead shot then there would still be part of the bar that would resonate. I'm also guessing that filling the bars with butyl rubber would completely dampen the resonance (eliminate sympathetic vibrations) and would eliminate all buzziness.Bar ends, I believe, change the resonant frequency of the bar so it vibrates at a different rpm but do not *eliminate* all vibration. In many cases, that's enough. If you can change the resonance to a frequency that the bike rarely generates or a rpm you are unconcerned about - fine. I was recently using rpms on a regular basis that one does not commonly use, i.e., 6,500 - 8,000.Unless I hear a good reason to try something different, I'll probably go with the Butyl rubber. I saw a 10 oz tube at the Home Depot for under $2. Even if I need 2 tubes for my taller Gold Wing bars, it's a cheap fix.
Doug Heinen wrote:I'll jump in for second here!The added mass will alter the frequency at which the bars will respond to vibrations that the bike emits. Example: most XS's have a distinctive _buzz_ around 3000 rpm. Some people have found that the exhaust system vibrates at this frequency. It is actually responding to the engine's vibrations and start to _resonate_ in harmony with those engine vibrations. By the same note, the bars will start to vibrate in harmony or _resonate_ with vibrations at certain frequencies emitted by the engine. Anyway, by changing the mass of the bars by adding heavy bar-ends, or loading the bars with silicone or butyl caulking and BB's you can easily change the frequency at which the bars respond to the engine. You can do the same thing with footpegs to eliminate buzzy pegs. However, most XS11's don't seem to have this. My old 750-4 Honda would tingle my feet to sleep in about 45 minutes!
John Higgins wrote:The rubber caulk might be a real good solution for you bike--I did not mean to question that fix, I just don't know how effective rubber is in absorbing energy which is what a damper typically does. I was just thinking the lower resonant frequency for the bars might be a good direction to head since I find myself cruising a lot at high rpms (5000+).
JP Honeywell wrote:Sounds good so far. On my recent trip, in which I used lots or rpms and gears in the twisties, I felt a lot of vibration in 1st & 2nd gear at around 3500 rpm and other gears around (I think) 6500 rpm. The resonant frequency of my fairing is about 1600 rpm. I don't know how effective rubber is either but it is used in the engine mounts and is reported to be much less buzzy than previous engines which were bolted straight to the frame.
John Higgins wrote:If you wanted to compute the resonant frequency of your bars the mode shape would probably look something like the action of a tuning fork. This frequency would be inversely proportional to the square root of the effective mass of the bars--with weight at the ends of the bars contributing most to lowering the resonant frequency of the bars. It would also be directly proportional to the square root of the stiffness of the bars--imagine putting a winch across the ends of the bars, pulling them together slightly and measuring the force and displacement of the fork. The ratio of the force/displacement is the stiffness of the bars for the resonant mode shape.
JP Honeywell wrote:Still hanging in there - but just barely. If you start with calculus, I'm outta here :-)
John Higgins wrote:Anyway, longer bars, or bars with weaker walls which deflect more, as well as heavier bars with more mass concentrated at the ends will lower the resonant frequency, which might drive your bars away from the high rpm excitation frequencies drifting up from the engine.
JP Honeywell wrote:and possibly also the road. I'm currently using Gold Wing bars (fairly tall) and I'm looking for even taller bars. I'm *seriously* looking for 7/8" ape-hangers. Maybe they'll be tall enough for me to sit more vertically. Unfortunately, as you say, longer bars may lead to more vibration rather than less. The proverbial trade-off.
John Higgins wrote:Adding caulking can help damping, which is another story, but the caulking also adds mass which lowers the frequency of the of the forks also.
JP Honeywell wrote:uh, did you mean handlebars or forks - or tuning forks?
John Higgins wrote:With everything being under a square root function these types of change are not as effective as you might hope--cutting the stiffness to mass ratio by 50% lowers the resonant frequency only about 30%--but as you say, a small change could mean a lot of comfort.
JP Honeywell wrote:Okay. So that's why mass is beneficial. So let me really screw up the concept. What do you think about this: What if I fill the central "U" with butyl rubber and the ends with lead shot or lead shot AND rubber? Do you think having the lead shot loose is better (like a deadblow hammer)? Would the size of the shot make a difference? Or have we gotten to the point of arguing the number of angels on the head of a pin? :-)
Doug Heinen wrote:It really isn't possible to add _too much_ mass, except that the XS1100 engine may bog down when trying to push 1500 pounds of lead along!! But seriously, did you ever stop to consider trying to resonate or vibrate a brick or 20 pound chunk of concrete! This would require _enormous_ amounts of energy at a very low frequency. So adding 2-3 pounds of lead in your bars won't hurt a thing. I like the idea of putting a 8"-12" tube on the tip of the caulking gun and adding a wad deep in the bars. Then you load them with lead shot of any diameter and then seal that into the bars with another wad of caulking. This should deaden that bars really well!!
JP Honeywell wrote:Concrete! Why didn't I think of that!?! The only problem is that concrete allows (perhaps even encourages) metal to rust. Hmmmmmmmmmmmm. I wonder what other (non-corrosive), dense, hardening-liquid options there are. So it sounds like the trick is to alter the resonance to a point that it is difficult for the motorcycle to create. But the only way to do it is by trial and error, I guess.My thinking on the topic went something like this:a metal tube or pipe will "ring" like a tubular bell when struck (or caused to vibrate). The same tube filled with water will just go "thunk" when struck. That's why I thought the rubber filled bars would respond the same way (only without causing rust or electrical problems). A tube filled with lead shot would also go "thunk" but I was concerned with loose shot pouring out of the bars if you ever had to replace the throttle cable. I guess you could put a little caulk in the ends of the bar after they were filled to prevent that. Until Johns' explanation of the effects of mass on vibration, the lead shot didn't make as much sense. Now I see that it takes more energy to vibrate a heavy object than a light object. I get it. The trick now is to determine *how much* mass. Bar end weights are not *very* heavy so I guess anything more than their weight should suffice. But is there such a thing as *too much?*
Les England wrote:In nuclear plants we fill the primary shield wall with several tons of a mixture of grout and lead. This is good for attenuating high energy gamma radiation (i.e. very dense, like this reply) and the reactor buildings do not shake very much! Caulk + Lead sounds like a great idea to me. Some use a similar approach in the stocks of shotguns to reduce recoil.
John Higgins wrote:I want to come back to a point I glossed over earlier, which is the distinction between vibration mitigation by damping and mitigation by adjusting the frequency response of the bars. The bars all by themselves have about 2% critical damping, which means that if you whack them with a steel hammer they will vibrate several dozen times, each time with a little less amplitude, until they stop vibrating enough to be felt. If we fill the bars with pookey, or just touch the bars near the ends they will stop vibrating much sooner. The reason for this is that the damping, or ability to absorb vibrational energy and convert it to heat, has been increased substantially.In my discussion I tried to focus on means for preventing either the handle bars or the rider's hands from picking up much vibrational energy from the rest of the bike. One way to do this is to change the resonant frequency of the handlebars so that they don't match up so well with the frequency content of the bike vibration which is the root of the problem. If for whatever reason, you design handlebars that vibrate at a lower frequency they just will not pickup as much vibrational energy from a high frequency bike vibration.
JP Honeywell wrote:So let me check something with you. Using my previous "tubular bell example, a longer tube [bell] would produce a lower tone, i.e., vibrate at lower frequencies. That by itself would reduce buzziness, right? Using that (unverified) logic, my Gold Wing bars would be better than stock bars. Wait, I think I know the answer already. The length doesn't matter as much as mass because if the frequency wavelength is one foot and I have a problem with a two foot bar, I'll see the problem again at three feet. So the length of the bars is a factor in resonant frequencies but changing the length just changes the frequency, not the damping. So that brings us back to mass.
John Higgins wrote:The idea about adding something which sloshes around like lead bb's, maple syrup, or maybe silly putty is interesting and in fact will take some of the energy of vibration out of the bars. But if you think about hands and forearms acting as dampers on the bar motion also, they are probably more effective energy eaters than almost anything you can put inside the bars--and we already know that they're not effective enough to suit our comfort threshold. That's why I think you might want to focus on preventing vibration buildup in the bars, rather than trying to take it out by adding damping--that's just too late in the game.
JP Honeywell wrote:I agree, my hands on the bars does a great job to dampen the vibration but, of course, the point is to prevent the vibration getting that far up the line. The reality is it doesn't matter if the vibration is eliminated (not terribly likely) or just brought below threshold (perhaps possible). A plumber friend told me in jest, "any leak that evaporates before it drips is not a leak." Vis a vis, any vibration that is reduced to the point below detection is not a vibration.
John Higgins wrote:My guess is a good way to decrease the frequency of the bars "enough" is to double the weight of the bars and focus the weight change near the ends of the bars. I like your thoughts about locking lead bb's in a fixed location (near the ends of the bars) with rubber sealant.
JP Honeywell wrote:Doubling the weight of bars is not hard with lead shot in the ends. In fact, it may be hard to *only* double the weight. The question now (since we're deep into the theoretical) is how loose or tight the lead shot should be packed. Keep in mind that the down-turned part of the bars will receive most of the shot even if a 10 oz cavity is filled with 5 oz of shot.
John Higgins wrote:I am just saying what I would try if I were bothered by vibrating bars. My situation with the Special is that my head is so buffeted by the wind that helmet vibration leaves me too addled to feel my hands or much else -- which isn't all bad. ;)
JP Honeywell wrote:Well, in all honesty what is a "problem" for me might not be a problem for most other folks. I experienced the "problem" after riding several days for 10 or more hours per day. Vibration, like noise, causes fatigue over time. It's a cumulative effect which produces a "saturation" kind of fatigue. My bars are nowhere near the problem of, say, a Harley. In all likelihood, my bars are no worse than (perhaps even better than) any other XS11. But after very long days of riding - especially hours of aggressive riding in twisties where the rpms are higher than "normal" - they cause my hands to become sore and my fingertips to become numb.BTW, I really liked your boat analogy. It made a lot of sense.
Stephen Burns wrote:There is also be an effect caused by the frequency of the bars. Vibration is caused by a wave moving through the vibrating object. The more rigid (and simple) the structure the better a wave moves through it without dissipating. Pipes, bars and tight wire (guitars, pianos) carry a wave best. Soft materials (rubber, caulking compounds, cloth) carry a wave the least.Vibrations in the same direct will accentuate each other and in opposite directions cancel each other out. One result of this is a standing wave. A standing wave is a vibration whose wavelength matches the length of the handle bar (or any bar or pipe, etc) or where multiples (2,3,4...) of the wave length match the length of the bar. The vibration moves along the bar reflecting off the end and traveling back up the bar. As the waves meet they either accentuate or cancel each other. Waves of the right frequency always cancel each other out at the same point(s). The visible effect of this is that the wave appears to stand still rather than travel up and down the bar.The closer to a standing wave you get the greater the size of the vibrations as they feed each other rather than cancel each other out. I believe a suspension bridge in the US tore itself apart because of this.If you get a vibration generated in the frame at a frequency that matches a standing wave frequency in the handle bar then the bar will resonate. The closer to the standing wave frequency, the greater the resonance and the more the bar will vibrate. If you change the frequency of the handle bar to one not generated on the bike then the vibration will be lower. Alternatively if you change the bar so that it won't hold a standing wave the vibration will also be lower.Changing the length or shape of the bar (even by a small amount) will change the frequency of the standing wave. Alternatively filling the bar with rubber or epoxy or whatever will absorb some of the standing waves energy and dissipate it without resonating to it. Lead shot will do the same thing. The more random the vibration the better as this tends to result in vibrations canceling each other out more.To decide which has the most damping effect I suggest a short experiment. Get a two foot (about that anyway) metal pipe (copper perhaps) from the local hardware store, drill a small hole in one end and hang the bar by fishing line, like a wind chime. Gently strike the pipe with a piece of metal (hammer, iron bar, whatever) and listen to the sound it makes. It should be a nice clear note. Next add the filling compound to the top ½ of the bar and when set strike it again, the note should be significantly muffled. Next add lead shot (small like bird or rat shot) to the rest of the bar and cap it with some more of the filling compound. Again strike the bar to hear what the effect has been. I think smaller shot would be better as this give more contact between the shot and the bar and the greater number of pellets would create more random vibration.Finally remove the plug, take out the shot and re add it mixed thoroughly with the filling compound. again wait till it sets and listen to the change in sound. I suggest the combination giving the dullest note would vibrate the least.You may want to try tape recording the sounds so you can replay them and hear them all at the same time, to remove some of the subjectivity.OK who wants to give this a go. I can't do it here as, over here, lead shot is ammunition and I need a gun licence to by it (no threads on guns etc. please).
John Aghajanian wrote:I've been think about this and finally decided to throw my 2 cents worth into the frey. All your ideas are wonderful but only if you have a source which produces a vibration of a constant frequency and amplitude. Since one cannot ride at a constant/unchanging speed/RPM's or accelerate/decelerate at a constant rate, or even ride constantly over a uniform, flat, straight (no hills or curves) surface: the frequency and amplitude of the source of the vibration essentially is changing constantly. Therefore, one must determine what conditions cause the most offending vibration frequency (or frequencies) and dampen/control for those specific conditions and, of course, live with vibrations under alternative conditions. OR one could come up with some sort of variable dampening control with, perhaps, a dial-in control that would move a mass along the length of the handlebars or a computer-controlled automatic variable dampening device (it IS the 90's you know).Just my thoughts on an interesting subject.
Rick Jemison wrote:This has been an interesting thread and I've thought about it quite a bit. I have an '81H full dress (Vetter fairing, bags, etc) and have made a discovery I thought might be worth a mention (it was a discovery for me anyway). For comparison, I have what I'm assuming are standard handle bars for this motorcycle. They come up about 4 inches and pull straight back as adjusted. Bar ends are at an angle of about 40 degrees from an imaginary line running from the steering head back bisecting the tank/seat (sorry if that isn't clear). I'm trying to say the angle between left and right bar ends is about 80 degrees. The angle from the bar center section to the bar end is about 115 degrees. These angular measures are "eyeball" so take with a grain of salt. I'm just trying to describe the bars so you all know what I'm dealing with (boy a pix here would be good!).I took a little ride through Illinois over the weekend (about 300 miles total). I have been having some numbness that I attributed to handle bar vibration on my bike. I have aftermarket grips (my son calls them Mad-Max grips). They are chrome steel (approx 1.5-1.75" dia) with raised rubber inserts running lengthwise down grip (about a half dozen around the grip). Whew!I noticed my left hand didn't suffer from the vibrations, only my right. I hadn't noticed this previously. I just assumed it was handle bar vibration. As I rode this day however I was trying to concentrate on the particulars and realized my left hand didn't hurt, only my right, which was getting numb and tingly. As my left hand wasn't really being affected (I rode for over 2 hours straight without any pain or discomfort) I felt that:
The difference between the two sides, of course, is the throttle mechanism. I reasoned that perhaps the grip being on the throttle sleeve was not allowing the grip to isolate the vibration on the right (and this might really be happening). In an effort to keep my hand as comfortable as possible I was trying to rest it on the grip, coast down the road periodically while resting my right hand on my leg, allowing it to stop tingling. At one point I sat up straight and just held on to the bars holding on with just my fingers wrapped around both grips (actually, I think I did this several times before I realized what was happening). I had no pain or tingling due to vibration. The long and short of this story is that I was leaning on the grips. This along with the slightly different angle on my right wrist, due to throttle position was making my hand go to sleep! I started sitting up straight and except for really gripping the grips tight (which still results in tingling) I have no more pain. It seems my pain was rider induced. Actually I don't notice much vibration through the handle bars (I'm a veteran of Triumphs/BSAs (both 650s), Hondas (450, 750) and Kawasaki's (500-700 triples)). Any of you familiar with these bikes knows what handle bar vibration is! My '81H does not have much handle bar vibration! I realize I may have a really good bike - but I don't believe that. I consider this machine typical of the species. That being the case, you might consider your riding position, grips, etc. I think one person mentioned having foam grips and was satisfied with them. I tend to grip them too tightly eliminating any dampening effects they might offer. But for others....
- there was no significant vibration in the bars or
- the grip on the left was dampening the vibrations out but the grip on the right was not.
Doug Heinen wrote:One variable you left out is the fact that we grip the throttle tighter in order to maintain the same throttle position and engine speed. (except for those riders with throttle lock mechanism-this won't apply) The tighter the grip the better the transfer of the vibration to our little hands!
JP Honeywell wrote:I have a throttle lock - and it still applies
Sid Hansen wrote:The more forward my riding position, the more weight on my hands, the faster they tingle and go to sleep. My solution...I put on the ram bars (on my standard) for more of a sitting straight up position, and foam grips. I now have a throttle lock for the highway also. The only draw back of the ram bars is the wrist angle, but I have become used to it.
Lanny Marshall wrote:I took a little ride through Illinois over the weekend (about 300 miles total). I have been having some numbness that I attributed to handle bar vibration on my bike. >> If your hand is going numb it's probably carpal tunnel syndrome. I can't ride any motorcycle for more than 30 minutes at a time without a cruise control.
Rick Jemison wrote:Don't even think it! My wife had both her hands done 2 years ago. She feels great now but, wow. I'm not into surgery. Maybe I can develop a handle bar that replaces the sissy bar!
Dave Butler wrote:Rick the proper position biomechanics wise is a 35 degree lordotic forward curve to the lower back and the neck should be a 45 degree curve, if you slump in the seat like a typical Harley rider not only do you increase the gravitational pressure load on the lumbar discs but you also increase the load on the cervical brachial plexus (nerves from neck into arms and hands ) by increasing the forward head posture and forward weight bearing of the cervical spine. Try this: sit up real straight and move your neck forward and back, it should move fairly easily without restriction. now slump back from your lower back like your sitting in your recliner feet up watching television, try moving your head forward and back, you should notice that it will bunch up or be restricted in the backward motion, now hold it there for 4-5 hours, see if your arms tingle. Many people that have been diagnosed with repetitive stress syndrome are actually the victims of their own faulty posture. When I get my %$@#$% scanner figured out I'll post some easy exercises you can do on and off the bike to reduce the stress of long distance rides.
JP Honeywell wrote:Well, I got my new handlebars. These are sort of low-ish ape-hanger bars that I bought from Flanders in California. Flanders is a company you've probably never heard of unless you're in the motorcycle industry. They have a good reputation in the industry. Here's why I wanted different bars. The original buckhorn bars were uncomfortable to me (and just about every moto-journalist who wrote about the bike 20 years ago). I rode thousands of miles with them and really made my wrists sore. I also didn't like having to reach for the handlebars. I like to sit straight up and I guess my arms are short. I bought a set of handlebar risers from Kevin Brady (whose arms are definitely *not* short). This moved the bars up and back about 1 inch in each direction. That was a *little* better in terms of reach but still did nothing about the weird angle of the grips.So finally, last year, I got the (used) Gold Wing bars. These bars alone would have made the reach *very slightly* better than the stock bars but combined with the risers was even a little better than the previous combo. The weird angle was gone and the reach was pretty good. Not perfect, though. Another inch or two back would be better. The problem is that I can't use the risers with my new bigger gas tank (more on that in another email). The risers wouldn't allow the handlebar to be turned more than a few degrees before it hit the tank. A local machinist (retired fellow) told me he could make me a taller riser for about $80 in a few months. I figured there had to be a better way.After a bit of searching and many telephone calls, I found Flanders. (800) 423-4438. After telling them what I was looking for, I got a fellow there (Juan) to fax me a page from their catalog. After seeing what I was buying and with some help from friends here on the list to measure the stock bars to make sure they would fit, I ordered my ape-hangers. I talked him down from over $50 to about $34. Shipping brought it back to about $47-48.These may not be something that everyone wants, but I was looking for three things:
Here's some technical details.
- a bar that didn't make my wrists hurt from a weird angle.
- a bar that allowed me to sit erect instead of hunched over
- a bar that didn't buzz as much as previous bars I had tried.
^ ^ |
/ \ / \ |
/ \ / \ |
/ \ / \ |
\ / D
\ / |
\ / |
A = the distance at the outside of the tubes where they go vertical
B = the distance between the highest part of the bars
C = the widest part of the bars
D = length of riser to highest point
Going just by the numbers, you can see that the Flanders bars are a bit wider at the grips. Not uncomfortably so but it is noticeable. The other thing that's kinda weird is how narrow the bars are at the mounting bracket. There's no problem getting them to mount, however. It's just a big difference from stock.
|Gold Wing (I think) bars
from local boneyard
|A = 11"
||A = 10"
||A = 9"
|B = 17"
||B = 13"
||B = 15"
|C = 27"
||C = 29"
||C = 33"
|D = 8.5"
||D = 10"
||D = 15"
From bottom to top, Stock XS11 Special "Buckhorn" bars, Gold Wing bars, Flanders Ape hanger bars.Notice below that the stock bars for the Special pull back quite a bit - to the point that the bar ends are holding the risers quite a ways off the ground. The end of the Buckhorn bars grips wind up at about the same place as the Gold Wing bars but they take two very different paths to get there.The Buckhorn bars are wider at the bottom (where they attach to the triple clamp) than the Gold Wing bars and come out kinda like a wheelbarrow. The Gold Wing bars are narrower and the riser is more perpendicular to the mounting piece. Then the grips come out from the risers.
From the other direction you can see the difference in grip angle between the Flanders bars (bottom) and the Gold Wing bars (middle)
I put my buckhorn bars on the ground next to my "Gold Wing" bars. In this photo, the risers are flat on the ground with the grips in the air.
You can see that the rise is significantly greater with the Flanders bars than with the Buckhorn bars.
There is also a greater rise with the Flanders compared to the Gold Wing bars.I've ridden about 80 miles with these new (Flanders) bars now and I am pretty happy so far. It was about 80-something degrees F the other evening and I took a two hour ride. Here's what I noticed. There is a noticeable buzz between 3,000-4,000 rpm. I think the birdshot in the bars trick will kill it. It's not very severe. [Slight digression to talk about vibration.]
The frequency of the vibration puts the buzzy part at different places along the handlebar.
_--_ _--_ _--_
_- -_ _- -_ _- -_
-_ _- -_ _- -_
-- -- --
__-- --__ __--
You can see from these drawings that at different frequencies (rpms) the wave crosses the centerline at different places. This would mean that at one rpm, the bar might be buzzy on the riser but not at the grips. I did notice this phenomenon.[end digression]
I also noticed another interesting effect. I was riding while wearing short sleeves. Because the grips are a few inches further out than the other bars, I was getting a nice breeze on them. (That might be a problem in the rain.) When I stopped at a light (after about 1-1/2 hours without stopping) my arms felt like ants were running up and down them. All tingly. As soon as I got rolling again and the wind was on my arms, they felt normal again.