[gpick]

I am posting the following even though it occurred on my wife's Burgman 650 because I think the handling issue is similar to that experienced on my Goldwing. Also, since there are many experienced riders here with mechanical expertise, I hope I may get some feedback useful to all of us.

The complete thread is: http://burgmanusa.com/ipw-web/bulletin/bb/viewtopic.php?p=152502#152502

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Was riding 2 up with my wife to get some Mexican food about 6:30 PM. Slowed for the right turn into the parking lot, going about 15 m.p.h, 20 max, and wham, my front end hits something and before I could blink the bike is on its right side. We were both wearing jeans and jackets with CE armor. I wasn't hurt at all. My wife banged her knee, but she thought she was all right. I righted the bike and rode it into the lot and parked. I asked again if my wife was O.K. and she said her knee hurt but she wanted to eat dinner and she would get some ice in the restaurant to put on it.

So I walked back to try to figure out what bit me. There was a patched section of asphalt with some compression dips in it where you could see trucks had beat it down. There were a couple of those that were rolling, not sharp, and then at the far end of the patch there was a section that curved up about 4" at about a 45 degree angle. About a foot past the lip of this a black skid began starting out about an inch wide and tapering until it was about 4" wide. The entire skid was only about 6 or 7 feet long.

I am trying figure out how and why this happened and how I could avoid such a thing in the future. Any ideas?

P.S. One thing I have learned is that this protective gear is worth wearing. Both of us were well protected in our upper body. The jeans are better than nothing, but are no substitute for armored pants. My wife's knee would have had no injury at all with the knee pads in these pants and I have a very slight bruise on my right hip bone right in the middle of where the hip pad is located in my riding pants. I can see this gear is quite effective on a low side crash.

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Subsequent post from an English Scooter safety instructor:

Think Brian has it. If a front wheel is unloaded while turned, it can `skate`.
My guess from what you say and saw is that the front unloaded off the earlier small `ramps` in the road, each cpmpouinding the previous, so by the time the tire came back in contact after it hit the big lip at the end, the wheel was already locked or at the point of locking - as you wouldn't have felt anything precisely because the tire was unloaded, you wouldn't have noticed anything was wrong until the tire came back in contact with pavement - by which time the wheel was already locked and skidding.

An extreme case of the problem of braking over `stutter` bumps - those which have no run-up but just raise vertically in the road. Hit a couple of those one after the other and effectively the suspension gets out of phase with itself and it's still trying to deal with the effects of the first when it hits the second... it's what manifests itself as that `clunk` from the front end and a sharp pain through the wrist!

But don't over-analyse this: Apart from going slower, whcih isn't an option unless you want to crawl everywhere at walking pace, I don't see what else you could have done, to be honest. Motorcycles are inherently unstable, and the only point of contact is the black rubber things at front and back. At 15mph you were above the `rear brake only` zone, especially with a passenger and those ripple bumps can be invisible in anything other than the brightest light.

Just be thankful, as we are, that neither of you was hurt..! Wink

Simon Evans
AN650 K3 `Gonzo`
AN400 Burgervan, 30,000 miles and still going... nowhere.

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My Response:


Thanks all, for the feedback. Brian, there was no tar snake. The entire black mark was rubber from my tire and it really smeared a lot of it on the road.

Snave, I have thought about this a lot since I posted and I think what you described is right with one other element.

I am fairly certain that my bike had not yet begun the turn. I am sure there was no lean yet. One of the reasons is that a mini storage comes right up to the sidewalk and I was looking to see that it was clear. The important part is that I had just finished braking gently or was finishing, but I am sure that both hands were on the brakes. The key I think was surprise. Like Pete, I was almost knocked off the bike and what I think happened is that as the bike tried to buck me off I reflexively grabbed to hang on, thus locking the unloaded front brakes. There was no rear skid track. Then, when the unloaded front wheel came down a foot from the lip the small skid began. Small because the from wheel was straight and because since the unloaded wheel was locked it immediately began to skid as weight was put on it. As the weight increased the width of the skid mark began increase. First, because its contact patch was increasing and then widening to 4" as the front wheel turned sideways.

There were three or four compression bumps leading up to the lip. The ridges of these were about 30" with curved bottoms approximating the curvature of a truck tire. At my speed I think the Burgman suspension was capable of following these.

As I said, there was no time to react after I reflexively grabbed to hang on. Wham, thud. Less than a second I would say.

In any event a valuable but inexpensive lesson that could have been quite expensive in another place and time. Therefore, I want to make sure I gain full benefit of it. My wife's knee looks much better this morning. Most of the swelling has gone. My right hip is tender to the touch with the tissue just sore over the hip bone.

So on to lessons learned thus far:

1. I cannot anticipate the unexpected, but I can require ATGATT. Neither my wife or I would have had any injuries whatsoever from this fall had we worn riding pants. My mesh ones would have been fine. I can see why so many serious injuries occur near home. They are not purposeful rides. The temptation is just to jump on and go. I have always required the jackets and boots, but have accepted jeans. No more.

2. Change the suspension. A dirt bike would have sucked this bump up without notice. Ironically, I rode the Burgman because the 12MM hex bit I had ordered had been lost by UPS. Otherwise, the forks would have been removed and taken to Race Tech to replace the damping rod with their cartridge emulator valves. This suspension may not have eliminated the bump but I am quite sure it would have reduced it a lot. I get the same harshness coming into my driveway 1 1/2 inch lip at 10 or 12 mph. My Goldwing felt the same unti I replaced the damping rod suspension. Now I cannot even feel it. I have to run an errand this morning. I think I will take the Wing and run over this bump a few times to test it. Slow and careful at first.

3. Upon reflection I find that I am much more cautious riding my Wing than the Burgman, because I know I cannot out muscle the weight of the Wing. I ride the Wing with more of the attitude I used to fly with. I was riding the Burgman with more of the attitude I had driving the Miata I used to own.

4. This last one, for now, is a question. Would ABS have been able to avoid this skid?

 

[richard h]

I am always concerned about hitting diesel fuel spills. That is the one thing that you may not see that is the most dangerous.

I encountered a diesel fuel spill on a freeway ramp. It was hidden by the recent rainfall. Fortunately, because it had been raining, I wasn't on my GW. My car lost traction on the front and headed for the guard rail. When the tires got out of the diesel spill they regained traction and I recovered.

If your front end of your GW looses traction like that you are probably going down! The only hope that you have is that you are not in a turning situation and that the spill is a small one.

Riding in or after a rain is always hazardous. Hidden potholes that only look like wet spots on the roadwy are like land mines. Best to slow down and go around those spots.

 

[dicepilot]

From my dirt bike riding days, I use the front brake strong while moving straight and very, very light when in a turn to keep the front tire rolling and in contact with the ground. If the front was applied moderately while the front tire 'ramped' into the air, it would probably lock up/stop while in the air and skid once back on the ground. Especially on wet pavement, gravel, or the accumulated debris at the edge of the road going into a parking lot.

Glad you and your wife are OK.

 

[gpick]

If the front was applied moderately while the front tire 'ramped' into the air, it would probably lock up/stop while in the air and skid once back on the ground.

I think that is the key and is what happened and this happened before I began to turn. I had only begun to think turn, not turn, when I "ramped up." The pavement was dry asphalt, no gravel. If I had just been cruising through I would not have been covering the brake levers and when I reflexively gripped I would have only gripped the bars. The gripping occured because the jolt even at slow speed was so severe as to throw my hands off the bars, hence the gripping. Also, if the shock had not been so severe I would not have grabbed the bars and with them, the brakes.

I doubt very seriously that I can retrain my reflexes and there are many situations where the gripping would be the correct one. My takeaway is that is one of probably a number of scenarios where lack of springing and damping can cause a loss of traction and even a skid. The Burgman has about the same 4" travel and hydraulic locking tendency that the Wing has, so I think the same scenario could have occurred on my Wing.

I have not had time to go back to this bump yet, but I am going to do so and test it with my Traxxion equipped Wing to see the difference.

I hope someone who is familiar with ABS can tell me how ABS would behave if the brakes were applied when the front wheel "ramped up" and became unweighted. I also suspect that if an unweighted wheel is stopped by a brake that it may skid when it recontacts the pavement, even when the same force if applied when the wheel has constant contact with the pavement would allow normal braking. We don't have as many potholes in California as other states because of our lack of rain, but after seeing what can happen I am reevaluating my riding strategy. It is one thing to hit a jolting bump, even one which could cause a bent rim. It is quite another when that bump can cause an unavoidable crash. We are not going to be able to see all of them.

 

[Gordon Frank]

A very experienced rider friend and MSF instructor had a serious fall on his silverwing... culprit was the center stand hitting a bump/rut in the road.
did you go back and check to see how deep the situation was ?
always smart to understand what might have caused any accident and determine if there was any way to have avoided it.
be well ya'll.

 

[Guest]

Gpick,

I feel you could have avoided this crash. Everything discussed here has been about the reaction "AFTER" the front wheel hit the road patch. In your description, I took it that you were surpised by the front wheel hitting the patch, basically, that you did not see the patch prior to the crash. You stated that you had to walk back to the crash site to discover what you had hit.

When approaching a turn off of the roadway, make a quick but thorough check of the pavement entering the turn and where the expected path into the parking lot is. "IF" there is any kind of unusual road conditions, such as potholes, uneven or stepped entrance, gravel or whatever, then adjust to avoid these areas completely, even if it means aborting the turn and make another attempt at another entrance into the parking lot, or make the block and make the turn at a better angle.

I feel that if just for a second or two, you let your concentration down, and then next thing you knew, you were laying on the ground.

 

[gpick]

No question that I could have avoided this if I had seen the bump. I would have anticipated the jolt and absorbed it with my arms. But I didn't see it. I will certainly be more alert to road conditions, but I am operating under the assumption that there are going to be times when you simply don't see something you should see. Night, twilight, riding into the sun, potholes in the rain (I don't ride in rain in California. No reason to.) all can produce the possibility that I might not always have a desired view.

My wife and I were talking about this this morning. She confirmed that I had not yet leaned into a turn because she always leans with me and had not done so. So this accident happened going straight at less than 20 mph. It happened so quickly that she did not know what happened either. So my concern here is that if a vehicle cannot transition such a bump without causing the rider to instantly lose control, I need to research how I can change the bike to improve my odds or, if that is impossible, change bikes as to one with ABS.

I already knew that the front suspension was deficient and many board members have acknowledged this as well. This is true of almost all lower cost production bikes. Damping rods are at best a compromise and the only reason they are in bikes is because they were cheap. I just did not know it could contribute to such a sudden loss of control and this is just one of many other conditions where the suspension could have made a difference. Loss of traction under hard breaking on uneven surfaces is a common condition caused by suspension that is not compliant and it is very common to have compression bumps at intersections frequented by large trucks, yet this is precisely the location good braking is often needed to avoid a t-bone. It seems to me that ABS brakes only as good as the suspension that supports them. The ABS can keep the tire from skidding, but that does little good if the suspension causes the wheel to become unloaded.

Keep in mind this is my wife's bike and she is a new rider who has not ridden on the street yet because I want her to take the MSF course first. If I am going to turn my wife loose on a bike I am going to make absolutely certain that I have done everything I can to make it have the best handling it can possibly have.

Suspension for many people is only about comfort. That is the byproduct. The main purpose of good suspension is to maintain the best possible contact with the road with this tiny contact patch we have on each wheel.

As I have mentioned, I dramatically improved both the ride and handling of my Goldwing by putting in a state of the art suspension with springs calibrated for the weight of the bike and rider.

So it appears to me that my crash was caused by my failure to identify a hazardous road condition which the bike's normal handling capabilities could not overcome.

 

[Teaser 1]

dumping bikes

Gpick, Don't be offended because I don't know you or your experience level. But just a reminder of fundamental riding technique: You do have to counterlean a bike at very slow speeds or it will dump like a ton of bricks. This is vital with a Wing and being alone or 2 up.

 

[gpick]

No offense taken, I have 10,000 miles on a Wing in the last 12 months. I have plenty to learn. Only 500 on the Burgman. I do understand that when one is going slow enough that the bike does not counterstear, that you do not lean with the bike in the turn. This is not applicable here. This happened BEFORE the turn began. There was no lean yet, period.

My wife says she leans when and where I lean. I think it would be better if she just stays put. Isn't that right?

 

[Teaser 1]

No offense taken, I have 10,000 miles on a Wing in the last 12 months. I have plenty to learn. Only 500 on the Burgman. I do understand that when one is going slow enough that the bike does not counterstear, that you do not lean with the bike in the turn. This is not applicable here. This happened BEFORE the turn began. There was no lean yet, period.

My wife says she leans when and where I lean. I think it would be better if she just stays put. Isn't that right?

Nope, to keep her in the proper position she should always be looking over your shoulder in the direction of the lean.

 

[gpick]

to keep her in the proper position she should always be looking over your shoulder in the direction of the lean.

Which lean, the bike or my counterlean? I understand the above for a normal turn with countersteering, but you had been talking about counterlean in a slow speed turn. What should she do then?

 

[Teaser 1]

to keep her in the proper position she should always be looking over your shoulder in the direction of the lean.

Which lean, the bike or my counterlean? I understand the above for a normal turn with countersteering, but you had been talking about counterlean in a slow speed turn. What should she do then?

The answer is, at both times. If she leans the opposite way or doesn't lean at all, you will have to counterbalance her as well as the bike. More or less depending on which position she takes. Remember her seating position is higher than yours and that raises the center of gravity somewhat. Don't get me wrong you can do it alone and 2up, it will just be more difficult. You should never have your passenger's leaning weight and balance working against your leaning weight/balance or even neutral to it. I have found it always puts the passenger in the proper position to tell them to look over your shoulder in the direction of the lean.