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Discussion Starter #61
Since the original post, I have had a chance to test out some different scenario's with the bike and I experienced dramatic differences in stability over various situations. Again, this is with a B running 42lbs of air and an 18"Jurock in down position.
To be clear, I never used the word "cure" for this. I asked what more experienced K bike riders did to "mitigate" it - reduce it. Secondly, I never said it was something I didn't feel like I could handle. Finally, the dirty air situation I am referencing is when I am riding in multi-lane heavy traffic at highway speeds. i.e. 4-5 lanes in your direction at 65-75mph surrounded by cars and semi's. "Riding free" of this is not an option because when an opening is created another car inevitably moves into it. There is a stretch of interstate near my house that is one of the highest traffic flow areas in town and nearly always has this type of traffic. That was my test area.
1) worst case scenario - 1 rider, suspension at 1 up, cruise, with SHAD 58 top case on and collapsed, moderate wind (10-12mph). This was the ride that motivated my post. Pretty wild. I read the term "gummy worm" used somewhere. I would not want to have to ride any amount of time in that situation. I may have been gripping to hard(?) but still it was hands down the worst I have experienced. This was my first experience riding in this type of traffic with the top case on.
2) After getting some input here, I removed the top case, put a 20lb dumbell in each panier, and rode that heavy traffic route again. First in 1up suspension, then in 2up suspension settings. Removal of the case had a significant impact, essentially back to my previous experience w the bike. Moving to the 2up suspension pre-load gave another dramatic improvement. Frankly, any buffeting with this setup was fairly minor even in the heavy traffic.
3) Put the top case back on w/suspension in 2up/road. I could definitely feel the buffeting again on the bike but no where near the levels previously when riding in 1up/cruise mode. Making sure I was light on the grips it was really pretty manageable.
4) Riding all week in the mountains in NC last week 2 up with the top case. Didn't experience unusual instability riding 2up. Most riding was mountain twisty's and occasional higher speed stretches, but we did ride I40 from Black Mountain back to south Asheville. First third of that ride was in light rain as a storm passed and still had moderate wind. Bike rode great, and had no unusual buffeting with 2 up on the interstate.
My conclusion, tire pressure up, screen down, suspension on 2up/road, and top case off is the best scenario for riding 1up in heavy traffic - no unusual stability issues. Ducking down a bit behind the wind screen also seemed to help a bit as did making sure I kept the grip loose. Top case adds little instability as long as there is a passenger taking up the air pocket in front of it.

This may be old news to many on here but its the info I was trying to get to as I get better acquainted with the bike. Appreciate the constructive suggestions on ride setting, etc...Big difference between making these adjustments vs "that's the way it is, if you don't like it [can't handle it] go ride something else".
 

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Since the original post, I have had a chance to test out some different scenario's with the bike and I experienced dramatic differences in stability over various situations. Again, this is with a B running 42lbs of air and an 18"Jurock in down position.
To be clear, I never used the word "cure" for this. I asked what more experienced K bike riders did to "mitigate" it - reduce it. Secondly, I never said it was something I didn't feel like I could handle. Finally, the dirty air situation I am referencing is when I am riding in multi-lane heavy traffic at highway speeds. i.e. 4-5 lanes in your direction at 65-75mph surrounded by cars and semi's. "Riding free" of this is not an option because when an opening is created another car inevitably moves into it. There is a stretch of interstate near my house that is one of the highest traffic flow areas in town and nearly always has this type of traffic. That was my test area.
1) worst case scenario - 1 rider, suspension at 1 up, cruise, with SHAD 58 top case on and collapsed, moderate wind (10-12mph). This was the ride that motivated my post. Pretty wild. I read the term "gummy worm" used somewhere. I would not want to have to ride any amount of time in that situation. I may have been gripping to hard(?) but still it was hands down the worst I have experienced. This was my first experience riding in this type of traffic with the top case on.
2) After getting some input here, I removed the top case, put a 20lb dumbell in each panier, and rode that heavy traffic route again. First in 1up suspension, then in 2up suspension settings. Removal of the case had a significant impact, essentially back to my previous experience w the bike. Moving to the 2up suspension pre-load gave another dramatic improvement. Frankly, any buffeting with this setup was fairly minor even in the heavy traffic.
3) Put the top case back on w/suspension in 2up/road. I could definitely feel the buffeting again on the bike but no where near the levels previously when riding in 1up/cruise mode. Making sure I was light on the grips it was really pretty manageable.
4) Riding all week in the mountains in NC last week 2 up with the top case. Didn't experience unusual instability riding 2up. Most riding was mountain twisty's and occasional higher speed stretches, but we did ride I40 from Black Mountain back to south Asheville. First third of that ride was in light rain as a storm passed and still had moderate wind. Bike rode great, and had no unusual buffeting with 2 up on the interstate.
My conclusion, tire pressure up, screen down, suspension on 2up/road, and top case off is the best scenario for riding 1up in heavy traffic - no unusual stability issues. Ducking down a bit behind the wind screen also seemed to help a bit as did making sure I kept the grip loose. Top case adds little instability as long as there is a passenger taking up the air pocket in front of it.

This may be old news to many on here but its the info I was trying to get to as I get better acquainted with the bike. Appreciate the constructive suggestions on ride setting, etc...Big difference between making these adjustments vs "that's the way it is, if you don't like it [can't handle it] go ride something else".
I'm sorry you felt that "it's the way the bike basically is" advise was unconstructive. That wasn't my personal intent.

From your comprehensive description above, I don't see where you really found a magic bullet. Even if you want to, possible relief actions such as removing cases and changing suspension settings are impractical or impossible to do on the fly. That's important because "dirty air" situations can be hard to replicate and anticipate. The bottom line is that the normal body and screen adjustments that you'd make on any bike are your tools on the K16.

What I did find interesting in your analysis is that things get better in the 2-Up/Road setting. It's counterintuitive since the setting raises you slightly higher. Last summer when I rode with my wife in 2-Up/Road setting through horrific Wyoming prairie wind blasts, I felt no relief, just panic and religion. ;)

Thanks for sharing your findings.
 

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"There is no low pressure area on the top of the floorboard as soon as you put your foot on it so it will not act like a traditional wing"
__
You may be onto something........ what if there were curved surfaces at the bottom of the floorboards, lol
 

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All kinds of shapes can act as a wing creating lift and drag. Just look at a modern F1 car or even a MotoGP bike for examples. It's something to think about when you're considering putting a windscreen on a bike that's the size of a barn door or other farkles that hang out in the relative wind.
 

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I will apologize in advance if I am lighting a fuse - hopefully not. I have read through some pretty contentious threads here related to this. It seems to be generally accepted that the K bikes (especially the GA and B) get pushed around in dirty air. This is not meant to debate the extent of that -- I'm interested in feedback re: what setup has been most effective in reducing it.
I have an '18 B. Fairly new PR4's, 7Jurock 18" screen, and just added a Shad 58 top case that I run collapsed unless its parked w helmets in it. I have found the bike to be absolutely rock solid in any situation other than 65+mph in multi lane traffic. In dirty air, it literally becomes a different bike. As has been mentioned, it is not felt as a "wobble" in the bars but the bike just demonstrates a side-to-side "twitching". I had the same issue prior to adding the top case.
Running the screen down and tires near max inflation seems to help but its still there and becomes an issue if ambient wind picks up any amount. I don't normally heavily grip the bars but maybe as this thing starts to wiggle around I do it unconsciously so will keep that in mind. Also per threads here, will try riding with more pre-load on suspension.
I love this bike and don't typically have to ride in multi lane interstate traffic, but its hard to avoid it some times so I'm looking for suggestions to manage it better.

What has proven effective for others in reducing the effects of this? Screen width, tire pressure sweet spot, anything short of strapping a duffel bag on the pillion?
having come off 2 Ultra classics _ they were rock solid in dirty air. They were also over a thousand pounds loaded- the k is much b lighter and much more fun
 
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