Noise with Side Cases

[RTmutter]

Hi all. Took my first road trip on my new to me 2015 R1200RT. I had a Givi top case and the 2 OEM side cases installed. At 65 MPH and above, a strange repeating sound occurred. It was a whomp, whomp, whomp type sound, similar to what can happen with a single car window open while going down the highway. It's wasn't overly loud but enough that I could hear it with my helmet on. It sounded to me like it was coming from the front of the bike. I first suspected the windscreen (stock) but tried various screen positions with no effect. I then thought an out of balance or out of round front tire may be the culprit, which was worrisome. After returning home, I took the bike on the highway at various speeds up to 85 MPH both with and without the side cases installed. To my surprise the whomp, whomp sound only happens at 65 MPH and above when the side cases are installed. I'm happy that the problem is not with a tire or worse but I am curious if anyone else has experienced this on their bike. Also, interesting that the sound is coming from the front or, if not, that is what it seemed like to me.  

[strataj]

From what you describe it does sound like it's the tires.  I hear this when I have Michelin Road 5 GT on the bike, I'm told the Road 6 GT do the same.  Love the tires, don't like the noise!  I ride a 22R1250RT.  What tires are on the bike? 

[RTmutter]

Michelin Road 5 on the front with about 1000 miles. Michelin Road 5 GT on the rear with about 4500 miles.

[dirtrider]

12 hours ago, RTmutter said:

Hi all. Took my first road trip on my new to me 2015 R1200RT. I had a Givi top case and the 2 OEM side cases installed. At 65 MPH and above, a strange repeating sound occurred. It was a whomp, whomp, whomp type sound, similar to what can happen with a single car window open while going down the highway. It's wasn't overly loud but enough that I could hear it with my helmet on. It sounded to me like it was coming from the front of the bike. I first suspected the windscreen (stock) but tried various screen positions with no effect. I then thought an out of balance or out of round front tire may be the culprit, which was worrisome. After returning home, I took the bike on the highway at various speeds up to 85 MPH both with and without the side cases installed. To my surprise the whomp, whomp sound only happens at 65 MPH and above when the side cases are installed. I'm happy that the problem is not with a tire or worse but I am curious if anyone else has experienced this on their bike. Also, interesting that the sound is coming from the front or, if not, that is what it seemed like to me.  

Morning  RTmutter

 

At 65mph+ that whomp, whomp, whomp sounds too slow to be a tire issue.

 

It could be related to the Givi top box disrupting the air flow causing a pressure disruption in the riders usual dead air area. Possibly in how the Givi top box air flow is interacting with the side cases.  

 

You might try with the side cases on but the top box removed. Or even try a different helmet as a test. 

[RTmutter]

dirtrider,

Good idea on running a test with the Givi topcase off of the bike while the side cases are installed. I have not tried that combination yet. Regardless, as long as the sound is related to airflow/pressure variations, I'm OK with it. The sound is enough to get my attention but not so loud as to be too bothersome while cruising down the highway.