Useable crossbar space

[WildFord]

I was wondering for those who already installed any brand's crossbar system...Yakima...Thule..Rhino..or the factory, what is the usable crossbar space dimension??

The reason I asked is this...tried to mount my Thule cargo box (a pretty old one) on top of my 530e with BMW crossbar for the first time. I realized there isn't enough usable room for the bike rack and the roof box to mount properly. I had to use a wire to hold down the box on one side due to the factory rack has the plastic parts around the tower that the roof box mounting bracket cannot go around (it made the crossbar a little too wide). I drove on the freeway yesterday late afternoon to test this..but traffic was bad I only got up to 50 mph for a few seconds.

if the BS, which I'm still waiting, has less than this bar space, I might consider buying a new narrower box. Tho I don't think i would mount a bike rack on top. I'd use the hitch system on the BS. but the BS seems to also has limited width on top.

tensile strength of these wires should be around 100 lbs. I hope i don't get that much of uplift force on the box consider the other side has the regular mounting bracket to support.

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[Escape2Bronco]

I’m not sure I’d want to use wire to tie my cargo box on the roof rack. Or at least I don’t want to be driving behind you.

The space between the rear rails is around 3 feet. Will depend on which bars you get.

 

[Jmuns]

The factory ones have less width than the Thule or Yakima based on how they attach to the rails. If you went with the 53in from Thule you’d probably have plenty of room for that setup. Factory I think you’ll be in the same situation.

 

[Jmuns]

Better question is what’s the minimum distance you need for that current setup? Then you’ll know if the 53 will work or go up another size. Search for threads on crossbars and you’ll see setups with the 53in and 60in bars

 

[WildFord]

I’m not sure I’d want to use wire to tie my cargo box on the roof rack. Or at least I don’t want to be driving behind you.

The space between the rear rails is around 3 feet. Will depend on which bars you get.

i better double or triple up the wires. 300 lbs should be plenty for half of the load. I can't see 600+ lbs uplift force on the box. that will bend and break the box before the support goes bad. but yeah...I get you. I'm concern as well. that's why I want to take a quick test before I take a long drive.

I definitely can see the factory bar also has much less space. but just few inches will matter. I'd appreciate if people can put a measuring tape across their bars. Also, this may be the good reason to get the longer bars to extend over the support tower. I used to do that just able to bring extra stuff on top of the car (bikes + box).



Good idea of measuring....I need min 38" usable space. prefer about 40".

 

[Escape2Bronco]

i better double or triple up the wires. 300 lbs should be plenty for half of the load. I can't see 600+ lbs uplift force on the box. that will bend and break the box before the support goes bad. but yeah...I get you. I'm concern as well. that's why I want to take a quick test before I take a long drive.

I definitely can see the factory bar also has much less space. but just few inches will matter. I'd appreciate if people can put a measuring tape across their bars. Also, this may be the good reason to get the longer bars to extend over the support tower. I used to do that just able to bring extra stuff on top of the car (bikes + box).



Good idea of measuring....I need min 38" usable space. prefer about 40".

I’d be more concerned with the amount of forced caused by the lift. Depending on the box shape, you’ll either get lift or downforce when the air goes up and over and below it. I suspect most are designed to create downforce more so than lift but I don’t know that for fact. Just something to be aware of.

 

[GulfCoastBronco]

OEM provide 39” usable space

 

[WildFord]

OEM provide 39” usable space

thank you!! that's the shorter side on the rear cross bar? I think I read somewhere here that the roof is tapered in toward the rear of the vehicle.

@Escape2Bronco , yes, it is the air uplift force is exactly I was concern about. the shape of the box may generate some downforce but the windshield directs air right up to the bottom of the box. so depends on vehicles and size of the box, aerodynamic forces will be different. I just read in a BMW forum that some guy did 120+ mph (in Germany) with a Thule on top. I think Thule says 80 or 85 mph max speed.

a quick calc for 80 mph wind on a 1 SF flat surface yield about 16 lb force. I think I'm Ok. double up the wire should be enough. but if anybody sees a Thule box on the 395 you know what happened

 

[Escape2Bronco]

thank you!! that's the shorter side on the rear cross bar? I think I read somewhere here that the roof is tapered in toward the rear of the vehicle.

@Escape2Bronco , yes, it is the air uplift force is exactly I was concern about. the shape of the box may generate some downforce but the windshield directs air right up to the bottom of the box. so depends on vehicles and size of the box, aerodynamic forces will be different. I just read in a BMW forum that some guy did 120+ mph (in Germany) with a Thule on top. I think Thule says 80 or 85 mph max speed.

a quick calc for 80 mph wind on a 1 SF flat surface yield about 16 lb force. I think I'm Ok. double up the wire should be enough. but if anybody sees a Thule box on the 395 you know what happened

The back is closer to 36 of usable space, the front is closer to 39.

I’ll keep an eye out for a Thule box if I’m in the area. Saw a full size pickup bed cap laying on the side of the road this week. Didn’t stop to see how it “was” held down.

 

[WildFord]

The back is closer to 36 of usable space, the front is closer to 39.

oh oh...that is not going to work. it would be the box only. no bike tray can go on the top of BS with large size cargo box. probably not an awning either.

thank you!

 

[Escape2Bronco]

oh oh...that is not going to work. it would be the box only. no bike tray can go on the top of BS with large size cargo box. probably not an awning either.

thank you!

Yup, I’d say you don’t want the OEM cross bars. Plenty of other options available though that should fit your needs.

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