Weird & concerning handling

[Shadowofshoe]

     So I was running on I-71 and passing a Semi on its right prolly about 80ish +/-, and the C-14 began to wallow,low frequency, but feeling like the beginning of a tankslapper--been there paid for it.  I rode for about an hour before, I think, I figured it out--my OEM top case on because of ride w/ wife sunday. I thought well ,not much experience with it, though I think it caused an airflow issue with one lightweight guy and the airflow back on to the case.
 
   I have the OEM Givi Mono and am wonder if anyone has experienced this ? I chuckled when I read the 80 MPH caution, but really?

      Mike

[Bob]

I have encountered some severe turbulence from passing a tractor trailer many times. Not to the point of a tank slapper, but pretty severe. For what it's worth, I pass them as reasonably quick and as far in my lane away from them as I can. I do not pass them on the right. I have a CDL for TT, and will tell you that visibility is much less on that side. They may not see you, which could be bad! 

[overthehill]

Top boxes have been the culprit for many of your symptoms.  Top boxes for ST1300's have not been available in the US, only overseas.  Police bikes have been the barometer for these types of problems.  Tank slappers have been experienced by all brands of police bikes except Harley's.  Won't go into that.  I have personally seen this on a Connie10.  Of course they did not test that bike in a wind tunnel.  Top boxes create a whole new aspect of tubulence.  They also generally fall outside the bike's "load triangle".  I don't have mine on unless with a passenger, or loaded for a road trip.  Dancing is great, just not at 80 mph+.

[stevewfl]

I've went in excess of xxx miles per hour with my huge E55 top box.....  and leaned over in the sweepers.  No issues to report.

maybe i just don't notice it cuz compared the the kneedragger bikes i'm used to this C14 is a big huge behemoth of a bike that feels not only planted but like the tires are digging into the tarmac

[overthehill]

Most reports that I am aware of happened in a crosswind situation.  Did you have that when you experienced your unstableness.

[overthehill]

Sorry, reread your post and you were next to a big rig.  Absolutely, that's the stuff that can happen with the top box.  Wyoming and MSF have the diagram of the turbulence from a TT.  Game changer.

[Shadowofshoe]

     Thanks for the feedback....I tried to recreate it on the way back to no avail (yea stupid but I wanted to know) when have ya'll noticed it with your top cases were the same situations going on.....I'm surprised at that speed.
   By the way with my wife on the bike was solid at 100+ although it then creates a bigger foot-print.

      Mike

[overthehill]

We were behind a one of my riding partners on a C10 with a 55.  NB on I-25 with a good crosswind, we could see his line change about 6-8 inches.  Stong crosswind from the west.  His bike is dead solid without the topbox and no problems with either a passenger or gear in front of the top box.  Yes, this time, it is the bike, or really, the top box.

[VirginiaJim]

The only handling problems I've had is running the stock shield on my 08.  Get a little back and forth every time I get close to a semi.  I'm running the Shad 46 which doesn't have that high a profile.  All of that virtually disappears using my CB Euro.  I run the stocker in the summer for the most part and use the CB in the cooler weather and when my wife is on the bike with me.

[koval68]

I'm running with Cee Bailey's Ultra Tour Dome windshield and Givi E52 top case with no handling issues to report at the moment.

[Rawman]

I have a VStream and a Givi V46.  Absolutely no issues in 22,000+ miles.  I leave the top box and bags on 98% of the time.  I have been WELL north of 100 mph with bags and trunk loaded, single and 2 up.  I am usually at 80 MPH on the superslab with the windscreen up about an inch with all different types of Tractor Trailers around.

BTW, I am 220 lbs, 6'2" with a 33" inseam.

[ninjawarrior1400]

I got passed by a F-16 in the 5th turn at Deals Gap last year....and he shook the extra tall Cee Bailey Shield a bit when he hit afterburner for a few seconds....so I just shifted into 7th gear for the 6th turn and passed him, and had no more issues with flopping of my shield~

Ninja

[YoDoc]

<snip>  Tank slappers have been experienced by all brands of police bikes except Harley's.  <snip>

Even the Harley cop bikes use a slimmer version of the stock box.

[Shadowofshoe]

The only handling problems I've had is running the stock shield on my 08.  Get a little back and forth every time I get close to a semi.  I'm running the Shad 46 which doesn't have that high a profile.  All of that virtually disappears using my CB Euro.  I run the stocker in the summer for the most part and use the CB in the cooler weather and when my wife is on the bike with me.

  The day before I was riding w/wife and experienced no problems at speed (she likes going fast and I am an accommodating husband )  I have noticed a little turbulence passing semis on this bike,either direction, but not the wallow. Anyone think its the windscreen as opposed to the case as thats seems to be most mentioned here? I am still leaning toward ...skinny guy and gap to a non-wind tunnel tested add on.

     Mike