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I'm looking to adding a roof cargo container at some point, and I noticed that in the MB accessories book, they have two options: Crossbars and a Roof Rack Basic Carrier. The book says that the Crossbars will work with the MB Roof Cargo Containers, but when you go to that section of the booklet, it says that the cargo containers "requires Roof Rack Basic Carrier".
I don't know if I will be going with the MB roof cargo containers, but the Roof Rack Basic Carrier does look to stand off quite a bit higher and I am wondering if that is necessary with the cargo containers? Even if I went with a Thule or something similar, is one better than the other?
I ended up getting a good deal on some crossbars and I put them on this past weekend. The back crossbar went in fine, but the front one didn't fit in the designated area, so it's a little back. Finding those marks was tricky, especially since the sticker on the crossbar made it seem like there were lines but in actuality there were just small dots.
At speed, they aren't bad noise wise. Haven't picked up a roof coffin yet, but I'm looking forward to the added space.
I pay almost no heed to the recommendations for where to install them. I put them on as far apart as necessary to optimally hold the load. Usually this is as far apart as possible.
I put them on loose, and tighten the adjusting bolts after tightening the clamps.
I pay almost no heed to the recommendations for where to install them. I put them on as far apart as necessary to optimally hold the load. Usually this is as far apart as possible.
I put them on loose, and tighten the adjusting bolts after tightening the clamps.
No, the cross bars aren't adjustable. They are designed to fit between the rails ar two points. You are probably referring to the Rack Basic, which I believe allows for more adjustments.
I tried placing the forward bar at the designated spot but the c-clap wouldn't reach the bar.
Now I'm curious. Mine are black, with kind of a flat aero cross section. There's a rubber pad that runs the length of each cross bar, with lock bolts accessible underneath the rubber pad.
They're kind of useless, except to hold stuff up off the rooftop. I haven't tried to mount any carriers, such as a Thule "coffin". All I've ever put on the rooftop has been hardware stuff like drywall and 2x4's.
Now I'm curious. Mine are black, with kind of a flat aero cross section. There's a rubber pad that runs the length of each cross bar, with lock bolts accessible underneath the rubber pad.
They're kind of useless, except to hold stuff up off the rooftop. I haven't tried to mount any carriers, such as a Thule "coffin". All I've ever put on the rooftop has been hardware stuff like drywall and 2x4's.
Hmm. Those are the same ones I have. How do you adjust the width? The only adjustments I can see is the clamp that holds them onto the rails. That clamp has to grip the inner railing that slightly protrudes down.
There is a sticker on one clamp of each cross bar that shows where the placement point is. The back one is supposed to go in the small cavity between the two "touch points" where the rail meets the roof. The other one goes forward of that, and I placed it the best I could (ensuring the clamp was holding correctly) but it wasn't as far up as the marks in the rails.
Hmm. Those are the same ones I have. How do you adjust the width? The only adjustments I can see is the clamp that holds them onto the rails. That clamp has to grip the inner railing that slightly protrudes down.
There is a sticker on one clamp of each cross bar that shows where the placement point is. The back one is supposed to go in the small cavity between the two "touch points" where the rail meets the roof. The other one goes forward of that, and I placed it the best I could (ensuring the clamp was holding correctly) but it wasn't as far up as the marks in the rails.
Is there a way to make them wider?
I had the same puzzlement when I got mine. They didn't fit where they were supposed to go. At first I did the same as you, moving the front one further back. Then I noticed these screws:
Loosen the screws on each side and the crossbar clamps will slide in and out from the center section.
The two crossbars are identical except for the stickers and the factory width setting.
beat me to it. I didn't get a chance to post but was going to say they have adjustment screws. I didn't see them right away either when I first mounted the cross bars.
I have had no issues with the box. Is it very solid even in cross winds or doing 85 in MT.
If you notice I did move the rear bar back a bit from where the manual and sticker says you should mount it. I wanted the box back as far as possible (without hitting the tail gate) as it reduces the wind noise and looks better. I get very little wind noise (don't even really notice it unless I try and listen for it) and I spread the box clamps as far as possible for distribution and sturdiness. Very happy with the setup.
beat me to it. I didn't get a chance to post but was going to say they have adjustment screws. I didn't see them right away either when I first mounted the cross bars.
Typical Mercedes. They arrive misadjusted, and with no instructions. "You vill figure ziss out on your OWN!"
Originally Posted by lotuni
I have had no issues with the box. Is it very solid even in cross winds or doing 85 in MT.
If you notice I did move the rear bar back a bit from where the manual and sticker says you should mount it. I wanted the box back as far as possible (without hitting the tail gate) as it reduces the wind noise and looks better. I get very little wind noise (don't even really notice it unless I try and listen for it) and I spread the box clamps as far as possible for distribution and sturdiness. Very happy with the setup.
I think you have it very nicely set up. Ironically, it would probably be more aerodynamic if you turned it around 180, but it would look hopelessly retarded.
I always put loads as far back as possible (again, with the tailgate limitation) so as to cut the wind noise.
I had the same puzzlement when I got mine. They didn't fit where they were supposed to go. At first I did the same as you, moving the front one further back. Then I noticed these screws:
Loosen the screws on each side and the crossbar clamps will slide in and out from the center section.
The two crossbars are identical except for the stickers and the factory width setting.
Thank you both! I see that I will be adjusting them a bit this weekend.
I can see why the rear one is supposed to go in that void - it seems it would prevent everything from shifting back if they were to get loose. I also know that most roof cargo boxes are pretty adjustable. Is it better to move the cross bar back or move the connectors forward?
Thank you both! I see that I will be adjusting them a bit this weekend.
I can see why the rear one is supposed to go in that void - it seems it would prevent everything from shifting back if they were to get loose. I also know that most roof cargo boxes are pretty adjustable. Is it better to move the cross bar back or move the connectors forward?
I think the void location may be more the load bearing weight running down the metal of the frame at the back doors. IF you look straight down where it mounts to the roof line that is the strongest point of the truck. everything just before and just after is glass. I've had the rails on for almost 3 years and they are very tight still. The clamps are pretty tight and have good grip.
As to the position, that really depends on the box and how much flexibility the box clamps have, based on the box you will have to play and find the best setup for you. Start with the back bar in the void and see how the box sets up from there. my box sat too far forward with the bar in the middle and with the rear box clamps in the forward most position, so I adjusted the bar based also on what someone else on this forum said. I never get anywhere near the max weight of the rails as the box's max weight is less than what the rails are rated for.
I think the void location may be more the load bearing weight running down the metal of the frame at the back doors. IF you look straight down where it mounts to the roof line that is the strongest point of the truck. everything just before and just after is glass. I've had the rails on for almost 3 years and they are very tight still. The clamps are pretty tight and have good grip.
I dunno; those rails are pretty stiff. And both rail end mounting points are over a bunch of metal. Frankly, it beats me why M-B was so **** retentive about the intended cross bar locations.
I had a Subaru Outback, and I used to put easily 2x the specified load on the roof rack, and there were no rules about where the crossbars were positioned. I guess maybe they have to accommodate the load being dynamic - that is, the car going over bumpy roads with a load on top. M-B also probably felt they had to cover their butts and tell people something, regardless if it was less than optimal.
I just put the crossbars on as far apart and as far aft as possible.
I think the void location may be more the load bearing weight running down the metal of the frame at the back doors. IF you look straight down where it mounts to the roof line that is the strongest point of the truck. everything just before and just after is glass. I've had the rails on for almost 3 years and they are very tight still. The clamps are pretty tight and have good grip.
As to the position, that really depends on the box and how much flexibility the box clamps have, based on the box you will have to play and find the best setup for you. Start with the back bar in the void and see how the box sets up from there. my box sat too far forward with the bar in the middle and with the rear box clamps in the forward most position, so I adjusted the bar based also on what someone else on this forum said. I never get anywhere near the max weight of the rails as the box's max weight is less than what the rails are rated for.
Thanks for detailing your experience. I pulled the trigger on a Yakima Skybox Carbonite today (REI has all cargo boxes 20% off) and will pick it up next week. I will try and post some picks once I have everything the way I like it.
07-16-2015, 05:31 PM
thule roof box
