Rack - ever tried this?

[mountainpete]

Hi,

Wondering, has anyone ever done something like this rack on a Toyota? Notice how it is tied into the bed and attached to the cab. I've always consider this a no-no as there is too much bed flex compared to the cab and the rack would snap or bend things in ways it shouldn't.

Thoughts?

Pete

 

[ntsqd]

Not something that I would do. Bridging the gap between the cab & the bed has always seemed like a recipe for disaster. Without something like the space frame of a race vehicle the cab & bed are going to move independently.

 

[mountainpete]

Not something that I would do. Bridging the gap between the cab & the bed has always seemed like a recipe for disaster. Without something like the space frame of a race vehicle the cab & bed are going to move independently.

That's always been my belief and why I haven't done it yet. But I'm seeing more and more pics coming from overseas that do it - just like that one on a Defender. So there must be more information out there.

Pete

 

[flyingwil]

Hmmm A defender might be differnt than on a Taco since the 110 is offered in both bed and full cab designs. I think it might depend on the application. I can find some pics somewhere on my old laptop that shows a rack that was designed on a Taco and due to the frame flex put huge dents and bashes in the roof on a Baja trip. Let me do some diggin!

 

[flyingwil]

ok can't find them... I think it was from TTORA, a black truck. Oh well, you get the point.

 

[Overland Hadley]

Not something that I would do. Bridging the gap between the cab & the bed has always seemed like a recipe for disaster. Without something like the space frame of a race vehicle the cab & bed are going to move independently.

What about the flex on a SUV, something like the 4Runner. Could you build a rack like this on a 4Runner? If it would work is it just because the body is one unit and the flex is figured into the design of the body?

I am often amazed by the amount of flex that is crated on my Tacoma with very little difference in wheel placement.

 

[sami]

What about the flex on a SUV, something like the 4Runner. Could you build a rack like this on a 4Runner? If it would work is it just because the body is one unit and the flex is figured into the design of the body?

I am often amazed by the amount of flex that is crated on my Tacoma with very little difference in wheel placement.

The body on a 4runner is no different than that of an FJ40, 60, 62, 80, 100 and so on.. They are all body on frame truck platforms. Which means no body flex.

The flex that is being put to question here is that of a truck (cab seperated from the bed). If an SUV had as much flex in the chassis as a truck, i'd expect the windows to blow out or create some sort of mess that wouldn't fly so well.

 

[ntsqd]

Well yes and no. SUV bodies do flex. Some more than others. With the single body of an SUV it acts to make the whole structure of the vehicle (body & frame combined) more torsionally rigid than does the separate bodies of a truck's cab and bed. If the cab & bed where one unit, and designed to be that way from the start, then it would be as much of a problem as it would be on an SUV body. Which is to say that it would be more rigid than separate parts, but by how much totally depends on which body we are talking about.
As an example, the body of my '91 Suburban is fairly torsionally stiff, but the body of my '84 FJ60 makes the Sub look like a semi-soft noodle. I only need to drive one tire of each up an embankment, and then open a rear door to demonstrate this.

IF, and that's a big if, the rack structure can tie the cab and the bed together and make them behave like an SUV body without tearing loose any of the attachment points, then the idea has merit. I my best guess is that by the time you achieve that you will have built an exo-skeleton space-frame instead of a simple rack.

 

[Ruffin' It]

What about mounting the rack to a vehicle's (custom frame mounted) rock sliders instead of the body? Get rid of the majority of the cab/bed/frame flex issue. Just a thought.

 

[KG6BWS]

ive wondered about this same kind of rack myself. personally i think it has more to do with the type of body mounts than the body or frame itself. i may be wrong on this, so somebody correct me if i am, but i thought the gen 2 (?) 4runner and the tacomas shared the same chassis just different body styles. if thats true then then the only real difference is the gap between the bed and the cab. if the body mounts were a stiff rubber or aluminum it should take away a lot of the flex. like i said, somebody please correct me on this if im wrong.

that being said, an idea i had tossed around in my head to do something like this on my double cab, was to build my rack, mount it to the bed, then use yakima cross bars on the roof. use u bolts to attach the rack to the crossbars, but leave them a little loose, possibly with a soft rubber "bushing" between the ubolt and the cross bar. it would keep the rack where its supposed to be, cut down on vibration, but still allow for some flex without tearing the roof apart.

 

[Overland Hadley]

that being said, an idea i had tossed around in my head to do something like this on my double cab, was to build my rack, mount it to the bed, then use yakima cross bars on the roof. use u bolts to attach the rack to the crossbars, but leave them a little loose, possibly with a soft rubber "bushing" between the ubolt and the cross bar. it would keep the rack where its supposed to be, cut down on vibration, but still allow for some flex without tearing the roof apart.

I am wondering if the truck in the picture has something like that going on. Look at the rack mount over the cab, it is huge. I bet there is something going on there that we can not see from the photo.

 

[WASURF63]

Rigwelder,

I've done something similar to that. Although my rack doesn't extend out over the cab / roof of my truck, my RTT does. I mounted a Thule crossbar to the roof of the truck to help support the tent when in use at camp (dynamic load). Otherwise the setup is a "free floating" system when traveling down the road (static). I tried the "loose u-bolt" thing and even several different positions with the crossbar. It made lots of noise and even a twisting sound up top anytime I encountered uneven sufaces on and off road. I eventually removed the u-bolts and mounted some thin strips of rubber gasket material to the top of the crossbar for the "bushing" effect. It makes zero noise this way. It has worked great over one year for DD and dozens of expo trips.
My RTT is solidly bolted to the rack at four points already, so I don't need or want the extra binding contact the RTT makes when bolted to the front crossbar. I wanted this setup to be strong, yet flex without tearing my roof apart either.

WS

 

[Overland Hadley]

Well yes and no. SUV bodies do flex. Some more than others. With the single body of an SUV it acts to make the whole structure of the vehicle (body & frame combined) more torsionally rigid than does the separate bodies of a truck's cab and bed. If the cab & bed where one unit, and designed to be that way from the start, then it would be as much of a problem as it would be on an SUV body. Which is to say that it would be more rigid than separate parts, but by how much totally depends on which body we are talking about.
As an example, the body of my '91 Suburban is fairly torsionally stiff, but the body of my '84 FJ60 makes the Sub look like a semi-soft noodle. I only need to drive one tire of each up an embankment, and then open a rear door to demonstrate this.

IF, and that's a big if, the rack structure can tie the cab and the bed together and make them behave like an SUV body without tearing loose any of the attachment points, then the idea has merit. I my best guess is that by the time you achieve that you will have built an exo-skeleton space-frame instead of a simple rack.

Thanks ntsqd.

 

[Overland Hadley]

Rigwelder,

I've done something similar to that. Although my rack doesn't extend out over the cab / roof of my truck, my RTT does. I mounted a Thule crossbar to the roof of the truck to help support the tent when in use at camp (dynamic load). Otherwise the setup is a "free floating" system when traveling down the road (static). I tried the "loose u-bolt" thing and even several different positions with the crossbar. It made lots of noise and even a twisting sound up top anytime I encountered uneven sufaces on and off road. I eventually removed the u-bolts and mounted some thin strips of rubber gasket material to the top of the crossbar for the "bushing" effect. It makes zero noise this way. It has worked great over one year for DD and dozens of expo trips.
My RTT is solidly bolted to the rack at four points already, so I don't need or want the extra binding contact the RTT makes when bolted to the front crossbar. I wanted this setup to be strong, yet flex without tearing my roof apart either.

WS

Do you have any photos of your setup?

 

[jh504]

Rigwelder,

I've done something similar to that. Although my rack doesn't extend out over the cab / roof of my truck, my RTT does. I mounted a Thule crossbar to the roof of the truck to help support the tent when in use at camp (dynamic load). Otherwise the setup is a "free floating" system when traveling down the road (static). I tried the "loose u-bolt" thing and even several different positions with the crossbar. It made lots of noise and even a twisting sound up top anytime I encountered uneven sufaces on and off road. I eventually removed the u-bolts and mounted some thin strips of rubber gasket material to the top of the crossbar for the "bushing" effect. It makes zero noise this way. It has worked great over one year for DD and dozens of expo trips.
My RTT is solidly bolted to the rack at four points already, so I don't need or want the extra binding contact the RTT makes when bolted to the front crossbar. I wanted this setup to be strong, yet flex without tearing my roof apart either.

WS

Sounds like on a Toyota truck something like this would be the best. The bed and cab of my Tacos definitely moved around a lot when offroad. If you had the rack in two pieces, one for the bed and one for the roof where each could flex indepently of each other you wouldnt have the problem. You would just have to keep it in mind and not have anything too rigid bolted to the rack, bridging the gap, or it would counteract the solution.