ARB Base Rack - Destroying my Sunroof (2 Viewers)

[RyanR]

It's been a few months since I installed the ARB Base rack, and I will say that while the design of the mounting rails and the rack itself is EXCELLENT their weird inverted air deflector is an awful bit of design.

When the rack has nothing on it the air deflector drives air straight into the front/top of the sunroof glass. I can take some photos if you want to see exactly how it sits and where the wind is directed. The problem with this is at higher speeds (And we're talking 45MPH+ not Autobahn speeds) it creates enough pressure on the sunroof that it starts to compress it downward into its seals. Then once you hit 55MPH or so the buffeting starts. And this buffeting is interesting in that it does not create much audible noise... but your sunroof glass begins to vibrate so you now have a ceiling mounted subwoofer directly over your noggin. It can create some impressive SPL! As you can imagine this vibration is less than good for the longevity of your sunroof mechanism and seals.

When I have stuff loaded onto the rack this problem goes away. In the summer the rack is generally empty 90% of the time as keep it clear to strap a 12ft raft with frame, oars, the whole kit to my roof and drive it all over Idaho. Now this looks like it would be awful but its actually incredibly quiet and smooth, more so than my Yakima cargo box I keep up there all winter for skis and gear. When I have the cargo box up there the buffeting and "Sub-roof" phenomenon cease. Just normal wind noise.

Anyone else with this rack experiencing the same issue with the inverted deflector? I have the cargo box on for the winter now so its not bothering me at the moment, but I will be working on a new wind deflector for next summer.

 

[jdha777]

I also have the full length rack with inverted diffuser. I haven't noticed this issue on mine, however I haven't been specifically looking for it. Did you observe this phenomenon from inside the cabin with the shade open?' ll look for it next time I'm on the interstate.

 

[RyanR]

I also have the full length rack with inverted diffuser. I haven't noticed this issue on mine, however I haven't been specifically looking for it. Did you observe this phenomenon from inside the cabin with the shade open?' ll look for it next time I'm on the interstate.

Yes, it is primarily apparent with the shade open. And I will say it was not something that was really detectable early on... I could feel a little "bass" pressure at certain speeds but it wasn't apparent that the sunroof was actually vibrating I thought it was just exterior buffeting, and it may have been the case. However over time it seems this pressure has begun to wear down the tension and seals on the sunroof to the point where placing my hand on the sunroof at 75MPH is like placing your hand on the cone of a subwoofer. I think there was a "break in" period where the mechanism and seal rubbers were too stiff for the glass to really get moving.

 

[nwfl4runner]

Their older style rack had the same inverted piece and I removed it instantly as it was doing the same thing, so you aren’t imagining things.

 

[TNLNDCRZR]

I have this rack in my garage but haven’t put it on yet. Buffeting would be a major problem. Can anyone else speak to this? Is this to be expected? Not interested in damaging my sunroof.

 

[bryson]

I've had the full length Base Rack on my 200 for a while now and I've never noticed ANY noise or buffeting coming from the sunroof. Mine is empty 95% of the time.

 

[jdha777]

This past weekend I took a long road trip and did not notice any excess vibrations or buffeting at speeds up to 85 mph. There were small vibrations that were similar to what you could feel throughout the rest of the headliner surrounding sunroof and I was not able to feel any excess 'give' as I pushed on the glass.

 

[RyanR]

Their older style rack had the same inverted piece and I removed it instantly as it was doing the same thing, so you aren’t imagining things.

Good to know others experienced this as well.

For the first 20,000 miles I had zero complaints, the racks was about the same as my previous Prinsu, super quiet. I believe over time the buffeting on top of the glass beat up the sunroof mechanism to the point that no longer has the upward tension to counter the downward pressure.

For those who are not exhibiting this issue try opening the sunroof but leaving all the windows up and driving down the highway. Just below 50MPH and right about 65MPH the buffeting and pressure hit's a painful level for me, to the point it is blasting my head so violently it blurs my vision. Maybe there is some resonant frequency that happens if things are aligned just so and a couple millimeters further forward or back in the install and you never see this issue? Maybe my IronMan bumper changes the airflow enough that it is responsible?

I am curious if the wind deflector with the lightbar cutout does not exhibit this issue as it takes very little change to the aerodynamics up there for this issue to totally go away. Strap on a few 2x4s, cargo box, bikes, firewood pretty much anything I put on the front 1/4 of the rack seems to break up the air flow to the point that this stops entirely.

I am also glad to hear others are not experiencing this issue. It's a solid rack and I love the utility of it. I would have to assume ARB did some real world testing given their scope, experience and reputation for well engineered product. it does make a fine RoofRaftRack

 

[jdha777]

I've had mine on for about 7k miles so perhaps I haven't had enough time for this to happen. I'm also curious about how you are able to open your sunroof with the full length rack. The bottom edge of the deflector sits only a few mm about the glass so the sunroof would probably break if I opened it or even tilted it open. I don't ever use my sunroof (controls diaabled) so I was OK giving up this feature when I installed it.

I wonder if the redesigned mounts for the 2016+ LCs account for out different experiences. The sharkfin satellite antenna housing caused clearance issues and ARB redisigned the mounts to raise the rack by an about an inch. The deflector I presume was also redisigned as well to account for the extra height above the roof.

 

[HSTexan]

I've had my base rack installed for about a month and a half and just completed a ~2k mile road trip out to and around Colorado and back. Total mileage is probably somewhere around 4k miles since install. At first I didn't hear a single thing, but after hearing how you described it I do feel like I can occasionally hear the low rumble from the wind. I usually leave my sunroof shade closed all the time which I believe helps dampen the noise. I did open the shade last time I heard the noise and placed my hand on the glass and only felt a very light vibration. I am curious as to the long term effects of this and whether any small adjustments made might help resolve this permanently. I have the slightly taller updated version to fix the sharkfin issues and my deflector is tall enough to both tilt and fully open my sunroof. I have driven with the sunroof open and the wind deflector seems to direct air above my head and more into the second row (this was around town and at highway speeds). I'm still very happy with the rack, but am going to keep a close eye on this for any potential issues that may pop up in the future. I have some edge trim/bulb seal laying around (like what you'd find on the Prinsu fairing) that I may try to put around the bottom edge of the deflector to see if that changes anything

 

[RyanR]

I've had mine on for about 7k miles so perhaps I haven't had enough time for this to happen. I'm also curious about how you are able to open your sunroof with the full length rack. The bottom edge of the deflector sits only a few mm about the glass so the sunroof would probably break if I opened it or even tilted it open. I don't ever use my sunroof (controls diaabled) so I was OK giving up this feature when I installed it.

I wonder if the redesigned mounts for the 2016+ LCs account for out different experiences. The sharkfin satellite antenna housing caused clearance issues and ARB redisigned the mounts to raise the rack by an about an inch. The deflector I presume was also redisigned as well to account for the extra height above the roof.

It does sit very close to the front portion of the glass but it does not touch when tilted up or opened.

 

[RyanR]

I've had my base rack installed for about a month and a half and just completed a ~2k mile road trip out to and around Colorado and back. Total mileage is probably somewhere around 4k miles since install. At first I didn't hear a single thing, but after hearing how you described it I do feel like I can occasionally hear the low rumble from the wind. I usually leave my sunroof shade closed all the time which I believe helps dampen the noise. I did open the shade last time I heard the noise and placed my hand on the glass and only felt a very light vibration. I am curious as to the long term effects of this and whether any small adjustments made might help resolve this permanently. I have the slightly taller updated version to fix the sharkfin issues and my deflector is tall enough to both tilt and fully open my sunroof. I have driven with the sunroof open and the wind deflector seems to direct air above my head and more into the second row (this was around town and at highway speeds). I'm still very happy with the rack, but am going to keep a close eye on this for any potential issues that may pop up in the future. I have some edge trim/bulb seal laying around (like what you'd find on the Prinsu fairing) that I may try to put around the bottom edge of the deflector to see if that changes anything

The bulb seal is a good idea and if the sunroof glass touches it, it should just compress. I think really any change would solve the issue. It seems like it is a very specific resonate frequency it hits at a couple speed ranges and all hell breaks loose. Any disruption of this perfectly tuned disaster eliminates the issue lol

It looks hilarious but having that raft on top is incredibly quiet. I'll run 75MPH with that thing up there it doesn't make a whisper.

 

[chriscosta416]

Did anyone even see if there was a fix or if this is part of the design?

 

[HSTexan]

Did anyone even see if there was a fix or if this is part of the design?

I had actually forgotten about this for awhile so it's funny you bumped this because I finally got around to putting some bulb trim on the fairing this morning. I haven't driven with it yet since I wanted to give the sticky tape some time, but I will post again tomorrow afternoon after it's been driven

 

[sdnative]

I think the Front Runner rack uses the same type of deflector. Maybe not as elaborate, but it deflects air down into the sunroof.

 

[HSTexan]

Pretty sure the thin bulb trim made it worse--it was only mildly noticeable on the highway before and with the trim it was very noticeable at any speed above 55 at a nearly constant rate. Not sure if a larger bulb trim would make a difference, with the only other option being making a standard wind deflector angled like a Prinsu or the oversized Front Runner.

 

[TeCKis300]

Is the deflector removable? Try that. Maybe even cut it down so it's not trying to deflect as much air downward.

 

[Endurbro907]

Interesting, I have about 7k on mine and have not experienced this at all. The noise from the sunroof being open is terrible at just about any speed though, luckily I have never been a "sunroof guy". Hoping that even if I don't see it that the pressure on it doesn't eventually cause a leak though...

 

[chriscosta416]

Well I reached out to ARB and they said they have never heard of any issues and pretty much refused to help or troubleshoot with me.

To clarify the issue I am having is where vibrations are felt on the sunroof (when closed) as well as the fabric part when closed too.
Very strange and disappointed ARB support refused to even listen to my concerns.

 

[Endurbro907]

I think the vibration issues you are experiencing were actually identified and corrected proactively during my install by Ollie @cruiseroutfit

I’d send you photos of his additional install steps if I was with my cruiser, but I’m sure he’d discuss over the phone.