Calling all Prinsu Roof Rack Owners!!

[pjku79]

I searched through the many Prinsu forums and didn't really see any mention of vibrations.

I just installed my rack (full length with cutout for light bar, no light bar yet) on Monday. It is installed on a 4th gen sport. I do NOT have the rubber foam thing at the leading edge of the wind deflector.

I am having pretty serious vibrations while at highway speed (60-70 mph). :frusty: Initially I thought maybe it was my Maxtrax that I had put up there, but I removed them yesterday and it still exists. Out of curiosity yesterday while feeling the vibration, I rolled down the window and stuck my hand up against the side of the rack. It felt like it was going into some kind of resonance.

Has anyone come across this before? If you did, how did you resolve it? Does the rubber fix it? My rack seems like it is pretty far from the roof itself, so I am not sure the rubber will be large enough.

My next question is how much did everyone torque down the bolts (bolts to roof, crossbars, screws on wind deflector? I was worried about stripping them out so I didn't want to torque too much.

 

[blackoutt]

More pictures of installs and info here, maybe try posting where more Prinsu owners will see it (including 5th gens)

http://www.toyota-4runner.org/5th-gen-t4rs/192917-another-full-length-roof-rack-option-prinsu-33.html

Yes there is more wind noise on the highway to be expected but no resonance. Post a picture of where you have your crossbars and wind deflector mounted. Most likely things can be adjusted to help quiet the noise. These are kind of "builder racks" that offer lots of adjustability but with that comes lots of tweaking.

I torque the cross bolts until I the lock washers were good and flat and I didn't feel like I was going to strip the crossbar aluminum thread. The roof mounting bolts I just redid last night and I torqued them "pretty tight" again no torque spec but they felt less likely to strip than the crossbars.

 

[pjku79]

Here is what mine looks like mounted. It is a little grainy because I blew up another pic. I have the cross bars at the rear most position of all of the large slots. It kind of makes them evenly distributed across the whole rack.

 

[SAC-CA-Runner]

Here is what mine looks like mounted. It is a little grainy because I blew up another pic. I have the cross bars at the rear most position of all of the large slots. It kind of makes them evenly distributed across the whole rack.

Couple of things I notice that may be causing:
1. No light bar in the cutout and wind is entering there and then getting underneath that first bar causing turbulence. Stick a light bar in there and see if it goes away.
2. I would need a much better pic and some measurements but to me your side pieces look thinner than mine. I can barely put my fingers between my roof and the sides of my rack. So it seems it's sitting very high either by spacers or wrong sides to the rack.

 

[pjku79]

I am going to try to put my light bar up there tonight to see if that makes a difference. I was hoping to do it last night but ran out of day light.

I think I am going to buy some shorter spacers like Blackoutt suggested in the larger Prinsu forum.

I have noticed some people seem to have a windshield that is closer to the roof.

With regards to the missing light bar being the problem. I am not sure how much of a difference the light bar will be since it is essentially a square box just like the cross bar. I was thinking about possibly getting a piece of plexi to cover the opening. I figured long term, this would be better for wind noise as well.

 

[Drunner97]

No wind noise and no vibrations, also no rubber piece. Even with my solar panel sticking up over the fairing about 1/8". My fairing is basically touching the roof though so it's a lot lower than yours is.

 

[pjku79]

No wind noise and no vibrations, also no rubber piece. Even with my solar panel sticking up over the fairing about 1/8". My fairing is basically touching the roof though so it's a lot lower than yours is.

Drunner, did you use the lower holes for the fairing or is yours just taller then mine? I have about a half inch between the roof and mine.

Even if I lower my down until the foot basically hit the ditch, I will still have a decent gap.

 

[Drunner97]

Drunner, did you use the lower holes for the fairing or is yours just taller then mine? I have about a half inch between the roof and mine.

Even if I lower my down until the foot basically hit the ditch, I will still have a decent gap.

I believe it's the lower holes, I'd have to look. I don't think I have any pictures of the sides on my phone and the 4runner is at home.

 

[pjku79]

Here are a few more pics of mine.

front

Side

rear bolts

 

[Drunner97]

Here are a few more pics of mine.

front

Side

front bolts

Hrmmm. That does look like it's sitting higher than mine is.

 

[Folsom4Rnr]

[MENTION=152901]pjku79[/MENTION] yeah, I have had a couple of different vibrations with my prinsu rack. At first, I had the cut-out, but no light bar too. That lead to the first cross member vibrating up and down when above about 45 mph... made a gawd-awful noise too. See the vertical red arrows in first attached picture. The solution was to lower that first cross member bar down to get it out of the wind (you can see the location in the second picture...moved as shown by red arrow).

All was good (or at least better) until I put the light bar on... then I got a new vibration... This time it was a left/right movement of the front of the rack... (see the left/right read arrows in the first picture for a rough idea where I thought it was moving). It didnt seem to happen all the time or at a determinable speed (that I could tell), so it took me some time to figure it out.

I double checked that everything was tightened down - no luck. So I figured it was just a new harmonic due to the different air flow caused by the light bar combining with the open space (between cross member bars) above my sunroof.

Well, Im still not really sure what caused it... but my "fix" seems to have significantly decreased occurrence and intensity (it still vibrates on occasion... but now its usually in cross winds or other less common scenarios). Anyway, to "fix" it... I added another cross member bar right behind the light bar holding cross member bar. I dont have a picture of it... but the red box in the second picture is where I put it. I'm, sure if I moved that new cross member bar back, closer to the front mounting point (see red oval in first picture) it'd further reduce/eliminate the vibration... but I havnt tried it yet and dont really want to block the sunroof opening and the vibration really isnt that bad... so IDK I might not ever move it.

Anyway, like [MENTION=117708]blackoutt[/MENTION] said... lots of tweaking... just keep playing with the configuration / spacing of the light bar and other cross bars and wind screens until you get it to a point you can live with it.

Hope that helps (at least some).

 

[pjku79]

[MENTION=142877]Folsom4Rnr[/MENTION], Thanks for the very good description. I am going to cross my fingers that my light bar does a good number on it. If that doesn't work I will start messing with other things.

I noticed that your front fairing is much lower then mine and looks to go higher as well (meaning the overall height of your front fairing is larger than mine). I also have curved cut outs on the side that you don't have.

 

[Folsom4Rnr]

[MENTION=142877]Folsom4Rnr[/MENTION], Thanks for the very good description. I am going to cross my fingers that my light bar does a good number on it. If that doesn't work I will start messing with other things.

I noticed that your front fairing is much lower then mine and looks to go higher as well (meaning the overall height of your front fairing is larger than mine). I also have curved cut outs on the side that you don't have.

Yeah, you're right... I didnt notice that before. If you recently got yours, Im wondering if that was a design change since I got mine about a yr & half ago. I believe CBI bought them... so maybe they're making changes ????

Best of luck trouble shooting

 

[pjku79]

On my way home from work I opened up my sunroof and sure enough, the front bar was shacking like crazy. I didn't get a chance to install my light bar last night, but I am hopeful that will resolve my problem. i will keep everyone updated.

 

[Hailmagnet]

I'm about to order this rack with the 40' led light opening. Are you guys having to black out the center of the hoods due to glare?

 

[Porqupine82]

I don't have any vibration sound issues however I mounted a GoPro while hitting some Nevada desert at approximately 80mph, upon watching the footage, the unsupported area on the front of the rack jiggles back and forth violently side to side. I have had the light bar on since instslling the rack, and multiple tents throughout the years. No vibration noises at all..

 

[aelarson]

Is anyone struggling with resonance or very loud wind noise with these in recent history? Want to revive an older thread if possible, as I am getting close to buying a 7/8 Prinsu!

Unfortunately I just had to pull off my Rola basket because of such bad vibrations at highway speeds (70+), so I’m a little nervous pulling the trigger on another roof rack!

Thanks in advance!

 

[Porqupine82]

I'm about to order this rack with the 40' led light opening. Are you guys having to black out the center of the hoods due to glare?

Glare bothered me so I went black. Pics on Instagram. Im overland_tennessee

 

[SAC-CA-Runner]

Glare bothered me so I went black. Pics on Instagram. Im overland_tennessee

I have never had an issue with vibrations or glare. Maybe it's because I'm Salsa Red? I'm liking your tent. What brand. I'll have to find you on IG if I haven't already.

Sent from my SM-G935V using Tapatalk

 

[neal0124]

No real input on the prinsu rack, but I remember people on the Ih8mud cruiser forum complaining about wind noise on their racks. Some people were wrapping paracord around the front bars on their racks. They'd wrap it tight but spaced out, like screw threads. It would create turbulence, enough to eliminate noise. Maybe something like these on the front wind dam might reduce noise and vibration.

https://buyairtab.com/product/black-airtab/