Truck rack strength

Odd question for the rack-meisters. I have a Toyota Tundra with a camper shell that is “tracked” for Thule mounts. I currently carry my boat this way, anchored to just the camper shell, with no problems.

However, I am considering carrying additional boats and/or gear and don’t really trust these tracks to secure that much weight all by themselves, so I am thinking of using a set of traditional Thule mounts on the cab of my truck and moving one of the load bars up there to distribute where the load is anchored: half on the camper shell, half on the cab. I may also be adding a cargo basket, as this seems to be the best method to haul my recumbent bike, so that could be in the mix, too.

The question is for anyone else who “splits” their racks between a cab and any kind of bed system. Any kind of issues with lateral movement between the two? I imagine it would be minimal, but thought I’d ask the Dumb Question of the Day just to be sure :).


weight limits
Thule has recommended weight limits for their stuff, that takes into account the various configurations. You might not actually improve that rating any by moving one set of towers to the cab. Better check that before spending money on the new towers.

And the limit will probably be in the neighborhood of 150# either way.

I don’t know if my load will ever exceed the factory recommendations - I should have specified that in my initial post (sorry).

It will be higher, but not THAT high. My biggest concern, though, is the lateral movement of that increased load if it’s not all anchored to the same surface, like it is now. I know there IS some lateral movement between the truck bed and the cab - however small it might be - and want to make sure it won’t have any negative impact on whatever might be lashed to either end.

But I guess after giving it more thought, it’d be no different than people who use the truck roof and a hitch-mounted rack in concert with one another.

Similar but different
Tacoma rather than Tundra and Yakima tracks and racks rather than Thule.

I’ve got one bar on the cab and two on the camper cover.

Normal load is sea kayak(s) on the cab and front cover bar. This gives me the least rear overhang.

No problem with differential movement between the bars, but I’m not doing any serious off road stuff.

Differential Movement

– Last Updated: Apr-14-10 3:05 PM EST –

Whether this will concern you will depend on where you drive and how fussy you are. I will admit to being fussy about such things, as well as being very attentive to how the frames of various different trucks act while in use, and this is something I've paid a lot of attention to when driving or riding in a number of different pickups. A good bump in the road can easily cause the roof of the topper shell to get half an inch closer to the roof of the truck, while on typical road bumps that movement is more like 1/4 of an inch. Don't forget that the frame also flexes in the other direction, though not as much. Rotational movement (seen as right-to-left motion) at the roof line can be as much as two inches in a "gentle" off-road situation, and I've seen some older pickups with more than twice that amount of shifting while off-road. The amount of rotational shifting at the roof line when angling the truck in and out of sloping driveways is more on the order of 1/2 to 1 inch. Also consider that carrying a heavy load inside the truck will make these motions noticeably larger.

I'm too fussy to consider that acceptable for most boats, but in actual fact, it's probably okay most of the time. All you are doing is causing the gunwales to slip and slide a little bit on one crossbar or the other (though if the straps are really cinched down tight, I have to wonder what happens when the two crossbars suddenly bounce closer together by half an inch), and twisting the boat a little bit. Even though I wouldn't do it, I've never heard of a boat being damaged by this sort of thing.

I do that
On my ford F-150, day after day.

I have one rack on the roof cab and one on the cap.

I carry two long sea kayaks and one canoe, and never have had a issue with torque, etc.

I have the cab rack mounts bolted right through the cab, and the same with the rack mounts on the fiberglass cap



that is what I thought
I figured the same thing when I did it. I had a nissan pickup and mounted a crossbar on the cab and another near the back of the cab. I never noticed any loosening or other issues.

I’ve been carrying
2 carbon/kevlar boats on different pick-ups for years with one bar on the cab and the other on the bed. The bed rack itself flexes and moves a bit whether there is anything on it or not. I don’t strap the boats down as tight as death and have had no damage due to flex between bed and cab. Of course, if I know I will be off-camber, I take it very slow.

Thanks everyone
Appreciate the feedback!

Just a warning
I would not do any back woods Maine logging roads with a rack on the cab and another on the roof.

There is considerable twisting of the body and the cab on the secondary roads. The kind of road that takes you four hours to go 25 miles, because of washed out culverts and three foot deep potholes that you may have to roll boulders into.

I carry wooden canoes and see that there is enough twisting on my camp road at home that I wouldnt want to subject them to damage.

Your road may differ and for over the highway where the racks are (apart from too close together ) is not a big deal.

I have an old Tundra with a Jeraco cap… We redid the rain gutter attatchments this year…the fiberglass is quite thick… Even with two boats though the load tops out at 100 lbs.

I have
I have a ford ranger and have hauled composite boats(sometimes 3) of all lengths 1000’s of miles on some terrible roads at times and have had 0 problems. I use 1 yakama bar on the cab,and have a rack on the rear of the cap.