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