For months I've been testing different tire pressures, checking front and back wheel alignment, trying to chase down the gremlins that cause speed wobble and all this time the cure was for me to eat more pancakes !
Both times I have had issues, it was caused or partially caused by the road surface, when they mill grooves in to the surface for ice, snow, and a bad front tire. Pretty sure my Heritage has a bad front tire because of a super bad road pot hole. I think it has a bad cord, that broke on the belts itself..
I crashed due to weave when I was younger on a pedal bike. It left me injured and with a bad memory in my head on riding bikes in general, powered or petal. The fear of suddenly loosing control for no reason in a seemingly unrecoverable fashion kept me off my bike for awhile, and even now with me riding miles each day on my bike and participating in mountain biking, I never push it too hard because of the fear of sudden weaving for no reason and crashing hard. I know it's cheesy and a bit dumb to have the fear, but I simply forgot the isolated incident after awhile. I always felt a nagging fear when riding at speed that made me never keep it up too long, but I havn't been able to pin it down (or even recognize it) until I saw this video and recognized the problem they described. So yeah, thank you. You've helped me solve a childhood mystery and put to rest a trauma I didn't even know I had. By watching this I feel alot less nervous pushing it on my bike, because I know what scares me, and I know how to solve it if it does happen. I really needed to see this and I didn't even know it. Thanks for posting this dude.
Same boat chief. The pushbike encouraged a wiggle by yours truly while at speed. Knocked my front teeth out of line and smashed my face on a kerb. 30 years later. Still got thegap in my teeth to prove it. and a built in fear of speed wobbles. I spent the rest of my days on 4 wheels.
I've watched many self acclaimed experts on you tube trying explain for 30mins with other peoples footage. This is by far the best. Clear concise with actual riders demonstrating at speed.
These guys are bad ass as well. Making the bike wobble on purpose looks frightening. This is my biggest fear with motorcycles. Well a lot of things like poor road conditions, which is common in my area make me fearful.
I used to own a step through Honda melody 49cc shopping moped and that thing always developed a speed wobble at 2mph which turned into an absolutely terrifying tank slapper at 4mph. I had chassis engineers weld on supports to stiffen up the frame, tried out every available tyre on the market and had the suspension overhauled countless times but nothing helped. I finally found the solution after fitting bigger after market racing baskets. Not only has it completely cured the wobble and weave, i can now carry more of my favourite soups when going shopping. Other bikers may scoff and laugh as i pass them at 180mph whilst racing home to warm up my chicken and vegetable broth with extra croutons, but i just stick one finger in the air and shout swivel on that suckers! I ain't no basket case.
This explains why in the Death Wobble videos you see on YT so few people recover. They all do what they are supposed to not do, and that's they sit upright when it starts to wobble when they're supposed to stay laying down. All we get told in the MSF is to roll off the throttle and hold steady.
@@PaulMappud funny how modern riding schools teach how to reduce the effects then isn't it. But you wouldn't know that as you probably haven't ridden a motorcycle since 1940.
@@razgriz380 : This vid is the best part of 50 years old, that's half a century Chuggnutt, since the mid 2000's bike and tyre tech has moved so far away from your Brough Superior's cross ply tyres and knicker elastic suspension your brain can't comprehend it, modern bikes DON'T do this...
I rode most of the motorcycles featured in this video and rarely experienced any of the problems displayed here despite the fact that I never weighed anymore than 9 stone. In the few cases I did experience weaving a top box was often fitted perhaps the worst I experienced in this case was a 250 MZ I also remember riding a Z1300 which weaved at 45mph at that speed its sheer bulk meant it had a mind of its own and it would take you all over the road.
I had a CB750 Honda (running Dunlop K81s) at the time this video was made. I never experienced anything like this wobble and weave other than on a grooved road surface. The most common problem I remember from that time, causing weave, was wheel alignment. The Yamaha XS650 was particularly sensitive to misaligned wheels. Those tyre pressure charts are a starting point for finding the best settings not necessarily the best for performance. Great conclusion!? If you have a top box which takes weight off the front wheel, this makes the problem worse. If you lean forward and put more weight on the front wheel it helps stop the problem. But we can't figure out what's happening here!!!
Reason I'm watching this is because a mate of mine has a '29 Norton 500. It's capable in theory of close to 100mph - although a major weave sets in at a little over 60mph - and I'm 14 stone and probably the lightest person who's ridden it. It does it to everyone. This video will give us some interesting things to try out I think - and if the lying flat stops it dead then we might actually be able to find out how fast it will really go. (Although we don't want to be blowing it up really - bits of it are kind of irreplacable).
The rider's body is acting as an air scoop. The faster you go, the more the wind pushes on you, reducing downforce on the front tire. Leaning forward gets you out of the wind to apply more downforce on the front tire. A big windshield that scoops air up and over making a still-air pocket would fix it, but reduce fuel efficiency.
I'd disagree about the fuel economy thing. A nice, clean aerodynamic shield is going to resist less than a big sail of human chest. IMO I don't even understand why motorcycles exist without windshields, I'd never buy one without one or at least a bike that has an aftermarket one available. All of these 1000cc nakeds are the dumbest thing ever IMO.
@@potatojake197 lol motorcycles are horrible when it comes to aerodynamics. The bike has to push against air moving across a human body on it anyway. It’s a pointless topic.
I've owned 7 motorcycles in the past 11 years, all different, from sports to big adventure bike. I've never once experienced anything similar on any bike at any speed, and im only 65kg. I think we take the modern tech for granted.
I have 2018 MT09.I experience wobble at 180km/hr, I weight 60kg，I try to change my riding position, I found that when I lie down on the fuel tank and the wobbling got away, the front got heavier and more stable than before.
This is mental, I rode motorcycles for years! I never experienced such a bad speed wobble as you are showing? Tyres like that old Avon speed master, which we called, skid-master, used to make your backside pucker a bit!? This was due to being square so when you banked over, you were running on a thin edge. I think that wheel balance and frame flex causes most of the problem, also the fork angle is better, if it is slightly steeper than normal.
I think motorcyclists and motorcycle engineers get this wrong. It has more to do with resonant frequency. Have a quick watch of a 'Tacoma Narrows Bridge' video to understand the concept of mechanical resonance in structures. Also watch some video on 'Resonance - forced mechanical vibration' or similar. Structures all have a degree of flexibility. They are mildly elastic and they have hinged components and elastic tyres full of compressible air.. Suspension with no damping will cause oscillation of a wheel at its resonant frequency. Steering with no damping will have a resonant frequency. Some damping is required. This can often be the rider's arms. In this very old video: 'Dunlop Wobble & Weave', one can observe 'low speed wobble' and 'high speed wobble'. Low speed wobble occurs when the hands are removed from the handlebars. Thus, the arms are the damper. High speed wobble is not corrected with the arms, but changing the weight distribution of the human by lying on the tank eliminates the wobble. Although the human is not 'wobbling', weight distribution alters the dynamics of the structure. My analysis is that some damping is required. It may be that a very mild damping would be enough to eliminate the wobble. Maybe a headstock full of grease might suffice, maybe with a baffle inside the headstock to create a mild pumping action. Sure, tank-slappers (high speed wobble) could be eliminated by altering motorcycle geometry, but that may take the bike out of ideal geometry. The wobble has more to do with resonant frequency of the combined effect of: - headstock/wheel/handlebar mass - the front tyre/road forces - the frame flex - the rider/frame mass distribution and flexibility - rear tyre shape/flex - swing arm flex Changing any one of the list has the potential to change the high speed wobble characteristics or to change the speed or frequency of vibration. Using a mild damper will remove sufficient energy to prevent the wobble in the first place. Studying engineering at university, I remember calculations of frequency of vibration of multiple masses on springs in series. If you change the any one mass or any one spring, the frequency of resonance changes. So, if you design a motorcycle, it will have a resonant frequency. This frequency will be unknown until you ride the motorcycle. The solution is either to modify the mass or flexibility or add a damper to remove energy. As an extra, some riders report that if you hold the handlebars too rigidly, a tank slapper is more likely to ensue. Thus floppy arms and a loose riding stance are likely to remove the high speed shake. When racing, I try to be relaxed on the bike and avoid being rigid so that I flex with the bike as it lurches around underneath me. I can use 'body instinct' to handle wheel breakouts or what have you. Some riders report that 'giving it a fistful' can 'lift' you out of a wobble. Braking has the potential to make the wobble worse. Certainly, when riding on dirt, acceleration can 'keep the front light' and help to ensure that any wheel break-away occurs at the rear wheel. Both front and rear wheel breakaway can be rapidly counteracted if the body is not tense from holding onto the bars and seat with all your might. Some riders report that high speed wobble is more likely to occur under braking. Again, this is caused by the change in relationship between the masses of wheels/frame/engine/rider and the flexibility (or spring action) between the multiple components including the rider. It is of interest that the forces on the front tyre fluctuate from side to side as the front wheel goes through a high speed wobble. These forces are capable of maintaining the state of resonance. Although we say "high speed wobble" the frequency is actually quite low.
What we have today that they didn't have in the '70s is dirt cheap compute power, permitting the following benefits: - detailed CAD geometry of the entire bike - widespread use of CFD for drag reduction; occasional use for identifying potential unsteady problems (unsteady simulations be 'spensive!) - ubiquitous use of FEA for: -- linear static analyses (to skookumfact and weight-reduct) -- nonlinear static and dynamic analyses (looking for weird sh!t like yielding behaviour, effect of thermals, etc.) -- modal analysis (resonant modes, stiffness, dynamic deformation charactetistics) - full-assembly rigid-body and flexible-body (enabled by the modal analysis) dynamics (what-fer identifying and fixing further weird sh!t) Much of this you can do on a workstation laptop nowadays, whereas even just a decade ago you really did need a cluster of some kind. Anyway, with all of these shiny new tools and a hefty dollop of good engineering judgement it is indeed now possible to calculate the bike's resonant modes, take away any sources of excitation and add the requisite damping during the design stage, such that this sort of self-exciting wobble has largely become a thing of the past.
I production raced a Honda CB750/4 back in the early 70's. In those days everyone was shouting about NIKKI tyres, they had the same tread pattern as the DUNLOP TT100's but were half the price. My mates who transitioned to these tyres all wore out their arses on the track, especially if the track was wet! [Apparently, they had a high Nylon content and were a "hard" compound]. I stuck to DUNLOP TT100's and never regretted it. A few years back, I bought a 79 CB750/4 from a guy who said he just couldn't ride it; too scary! My first outing on it also scared me so I started investigating, tyre pressures, alignment, fork oil, tyres - and the tyres worried me. It had a square profile rear tyre - like the old AVON tyre. I swapped out the tyres for a new set of DUNLOP TT100's and it was a totally different bike! I could take my hands off the handlebars and simply steer it using my arse. The issue with high-speed weave is the wind pressure. Lie down, slow-down and then sit up. The same issue occurs when towing with a car, if the trailer starts wobbling - do not hit the brakes, rather accelerate out of the wobble and THEN lift your foot off the accelerator and let wind pressure slow you down to when you can apply the brakes. Really cool video, makes me wonder how we ever rode those bikes!!!!
My very first road bike was a 1981 GPZ750R1... It had a hinge in the middle of frame at 90.... My next bike a 1984 GPZ900 A1 was like night n day in comparison. My current MV Agusta Dragster is absolutely awesome.
Don’t ever remember my 71 Commando Combat doing that in the 70’s. Nor any Triumph , and we didn’t used to hang about! Only time I’ve seriously experienced it is quite recently on my CB1300 after a magpie flew into my shoulder at the sedate speed of 130kph. Felt like I’d been hit with a baseball bat and still hurts after 2 months. Induced one hell of a tank-slapped and I thought I was going to drop her.
Ive experienced this and reduced the effect with bolt on steering dampers. Later on in life I became fond of one brand of tyre that seemed to cure some of this. A matching pair of Metzelers
I've noticed every single one of these old bikes has a super thin front tire, some of them in the rear too.. Willing to bet that a larger tire helps reduce this.
I let go of the handlebars on a 2014 BMW C Evolution at 20 mph and handlebars wobbled. I chose sail mode and decelerate from 50-40 and wobble. It is restricted to 75 mph. Great video I have 1988 Honda CBR400RR fortunately lie over tank. Thanks for posting.
I stumbled across this old Dunlop film when looking at a post about Steering Dampers on the VOC ( Vincent) Forum. It is so far 19 pages long. There is so much to this subject about tank slappers, wobble weave that seems not to be addressed here along with other variables like steering head angle, trail ( front wheel axis to line of fork) and other meaningful stuff. Frankly this old 45 year old causes me more worry and willies. This is an early explanation of the subject.
My old Bandit 1200 had a bad weave, but I finally figured it out as the fork settings were completely wrong (too hard)- once dialled in it never as much as twitched after that.
Old bonnies I've had used to fish tail and were notorious for most people found the bsa frame was the best solution the triumph swing arm was to flexible by design it made no difference what tires you tried but it was fun all the same
Most weave at speed can be eliminated by wheel alignment. 60's and 70's bikes were notorious for having poorly referenced chain adjustment marks. Any motorcycle can be improved by using string, eye, or angle iron methods to make sure the bike is actually single track.
Weird. I rode big bikes of that era as fast as they could go (and I was John's weight) and never had either the wobble or the weave. Perhaps because I never fitted Dunlops? ;-) Actually K81s were known to have low directional stability and swapping to Metzelers, with high directional stability, would often rectify issues - we're talking racing speeds though. But really, this kinda beggars belief, can you imagine Kawasaki selling a Z1 knowing it would go into a death wobble well before hitting top speed? I can't.
When I bought my guzzi lemans I worried that the knackered steering damper might cause a huge weave . It never did and now I know it was due to me being a huge and heavy bloke . Thank god for bacon rolls .
If the wobble gets worse when you add weight to the rear, it seems obvious that lying on tank moves the weight to the front (and the drag also decreases which also takes the weight from the rear) and that cures the wobble. Having passenger in the rear increases weight significantly enough to remove that factor.
When I rode 900 lb. Suzuki cavalcades, they would do this when front tire was cupped. Loved the bikes, no problem at all after I started running Metzler tires. Dunlops were the worst. The only time I have this happen on my Harleys is when they have Dunlops.
Used to happen to Me al the Time on My Z1b in 1978 Worse than any of those situations, used to do it for fun after a while and scare my mates. wish I'd known at the time to duck down a bit. turned out to be a dodgy back tyre, regarded Quality Dunlop Red arrow. I always wondered why My tyres arrows were not painted red and had no red line on the sides till I changed the tyre and saw the regarded quality stamp.
It could be leaning forward moves more weigh to the front wheel, curing the imbalance. Modern bikes as I understand it have stiffer fork springs fitted, and stiffer frames, but still can suffer from it.
I`ve beenriding for 50+ years and only experienced a tank slapper once -- swing arm pivot was worn. I use a Royal Enfield 650 as an everyday ride these days and have not experienced any of these problems . Could it be that I am a fat sod ( 15st ) or just bloody lucky
So they have a idea, but nothing conclusive more Pan Cakes seems to help but transferring weight forward appears to also work, Drive carefully, the life at risk is yours!
I wonder if the bikes favoring the heavier person was a result of the average suspension setup of the time and therefore could have been adjusted to be stable for the lighter rider.
They add a passenger and weave doesn't occur. They add a heavy box in the same location and it gets worse. So it's not simply mass. The human body offers dampening as well.
Calvin Hulburt You're right about body being a dampener, but that heavy box and passenger aren't exactly the same thing. Box weight is behind rear wheel. Passengers isn't.
jothain Yes the farther to the rear the weight is placed, the greater the effect on oscillations. The box weight is much smaller than the passenger weight however and the passenger and rider are not rigidly coupled to the frame. Passenger mass will be out of phase. There is a paper with similar experiments done with a title something like, A solution to the front end flutter problem.
Cool piece of nostalgia but, a bit outdated. With 20+ years of riding (the first Kawasaki super bikes) I never experienced this unless my tire(s) was out of balance or the bearings were worn. Me and my friends would race at 100+ mph through the hills of Austin in the late 70's (oh, the things we did when we were young 🤦♂️). Also, I graduated AMI Daytona Beach in '82 so I definitely challenge this info. If it wobbles there is something wrong mechanically. Side note: the Kawasaki didn't wobble even when forced to. Thanks for the trip of nostalgia.
I haven't had any wobble problems at high speeds from my Z1 Kawasaki or the 650 BSA Lightning. Both bikes were fitted with TALL and FAT rubber on both ends. At a 140 mph, you don't need this wobble. It could be deadly.
These modern peanut looking superbikes will be long forgotten, as most of them already are, before the Kawasaki Z series fade from memory. They are just so beautiful to the eye.
MY 2009 KLR,STARTS AT 60,COWASOCKIEE OF KOREA, LOTS OF PROBLEMS,THERMO BOB? DOO HICKEY? STARTER SYINDROME? SUB FRAME BOLTS,SNAP AND FALL OUT, CABLES+WIRES RUB THROUGH? EATS BATTERYS? NO RECALLS? BOUGHT TO RIDE,NOT WORK ON? BIG HEAVY, SLOW COW,
