Just finished a thule rack (480 mounts) install on my 2009 Ford taurus.
How many follow the the thule instructions? 9 3/4 inch from front window and 27inch apart (crossbars) thats what i followed. Just seems a bit narrow for a 16.5ft sea kayak.
For those you have sedans how far apart are your crossbars?
Thule
When I got the tracks for the roof of my truck, the instructions said to put the outer edge 4 inches from the crease line above the doors. I put them 1 inch in, and if doing it again, would put them 1/2 inch in. The “problem” was inner panels to strengthen the roof below the outer skin. Setting the drill stop to just penetrate those, made things easier as the bottom of the expanding nut was supported when starting to tighten the installation screw. You do have to make sure there is enough room for the nut to expand above the inner steel.
Harry
It IS a little narrow, but…
– Last Updated: Jun-20-12 11:47 PM EST –
that's the dimensions that they felt were strongest for mounting to your car, and how they engineered the fit for your vehicle.
On the upside, you're only two inches shy of what they feel is minimal for sea kayak use (30"), and as long as you're using a good saddle system, and tying down under the front bumper (if not both front and rear), you should be fine. If you haven't bought saddles yet, look at J cradles before upright saddle mounts, since they are less likely to deform your boat if you're using a plastic boat on slightly narrow bar settings.
30 inches
Should i move them to 30inches? I guess the rear can come back 3 inches.
I use a set of hual a port j cradles
Put it where Thule tells you!
Engineers with expensive degrees and experience spent time determining where on your roof crossbars should be positioned. If you think you’re smarter than them, then by all means, install your roof rack in a way that suits you, but do not be surprised if one day the rack fails.
If you are concerned about rack spacing, Thule has the excellent Slipstream cradle system which will offer plenty of support for long boats.
Photos
Heres two photos of the 27inches apart -
http://jdnphotographyclients.net/Thule480-2.JPG
http://jdnphotographyclients.net/Thule480-3.JPG
Anyone else using J-cradles for 16.5 or longer sea kayaks with that same cross bar spacing 27inches
You’re fine. Don’t Change
Put on your Hull-a-ports and you’re good. No need or reason to move anything further apart, because
- Thule says you shouldn’t, and
- With the radius of that roofline, you’ll end up with cradles that are pointing off in two very different directions anyway, providing a less secure carry for the boat.
Saddle up and go paddle.
gotcha
thanks everyone!
Its not 30 inches for all cars
Wait, the instructions for the thule feet for my dodge said that only 24 inches of separation were necessary…where did you get 30 inches from??
It may vary by the design of the adapter feet.
Its not 30 inches for all cars
– Last Updated: Jun-21-12 12:00 PM EST –
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Thule is not always right
Thule isn’t always right. They instruct you to strap your boat to the J-cradles, not the crossbars.
I stretch the span 6"
…and have done so for four years, with numerous trips, and no sign of failure.
Not to minimize the engineering effort, but for one, engineers like contingencies, and secondly, thule like to sell stuff.
I often doubt Thule’s advice
– Last Updated: Jun-21-12 2:07 PM EST –
Let me preface this whole rant by saying this applies to the usual situation of clamp-on tower support feet, where the clamping part grips that edge within the door opening. If your rack mount bolts to the roof, of course you want to bolt through whatever reinforcing members are present, and not just through the exterior sheet metal. Still, the reinforced zone is "right there" and available along the full edge of the roof, and I bet Thule could design bolt-on feet to fit at better locations for bar spread while taking full advantage of that reinforcing if they really wanted to, though I bet they'd need a lot more variety available foot design.
*************
Yeah, yeah, highly trained engineers and all that. Still, the crossbar mounting points are right along the edge of the roof, where there's already a tubular "wrap" of reinforcement. Is there really any benefit to making sure the mounts are located right where there's a cross piece of reinforcing too? Here's my thought, which applies to a friend's small car and canoe. You put this big ol' lever arm of a canoe out there in the wind on a pair of crossbars just 18 inches apart because that's what Thule says to do. You could put the racks 3.5 feet apart and drastically reduce the prying action of the canoe on the mounts caused by wind, AND reduce the strain on the boat by the same amount, and thereby stop most of that squirming action of the boat in the wind. Further, the crossbar mounts would be near pillar supports and/or front/rear edge-of-roof reinforcement, which are the strongest parts of the roof by far. Does Thule really think that those reinforced edges on each side the roof (especially at pillars or front and rear edges) are not strong enough to tolerate the much LOWER amount of wind-caused stress if the crossbars are far apart, but that greatly increasing that wind-caused stress by putting the crossbars extremely close together is okay just because there's a miniscule strip of reinforcing at that location which is only there to keep the sheet metal in the middle of the roof from flapping in the wind? That makes no sense to me since there's no way wind-on-boat stresses are going to overstress the reinforced edges of the roof. The boat will break before that happens, so why not reduce that stress in the first place by putting the crossbars farther apart? I suspect that what Thule is REALLY doing is ignoring wind loads and looking for every bit of extra strength that's available for carrying weight without running the risk of having crossbars too far apart to carry cargo boxes. In other words, I think they are looking for the strongest weight-carrying part of the roof within the center area, which is where people want their cargo box to be. Paddlers aren't carrying much weight and actually benefit by keeping bars out of the center-of-roof area. Until Thule justifies their instructions, or tailors the instructions for boats versus cargo boxes, who know what they are thinking? Until then, I'm convinced that consideration of wind loads is not part of the decision-making process.
that reminds me of another possible
influence.
Lawyers.
Read the Instructions before doubting
Honestly if you read the Thule instructions, you would have seen that they tell you to tie the front AND back of your “ol big lever arm” to the bumpers.
They even supply a little pulley/hook system to make it easier.
Not only would that remove torque arising from wind load but it would provide a redundant means of securing the boat in the event you did not tighten the mounts properly, or in the event the sheet metal under the feet has been weakened by corrosion.
I have no problem if a cop stops someone for not tying down their boats properly. The point is to keep the boat on the car even if their is a collision or rack failure.
27" is fine
I wouldn’t worry about it. 27" is fine. I have a Hyundai Accent coupe, and even with a short roof adaptor, my crossbars are only 26" apart.
I regularly carry 17’ and longer sea kayaks with no problem. If you use J-cradles and bow tiedowns you’ll be fine.
You have to read all of the instructions
Your supposed to tie and the front and back of your boat down to the bumpers.
So if the cross-member J hook wasn’t installed properly or has become loose or rusted, you wont have a calamity on your way to the launch.
So its ok to tie the straps just to J mounts-- in fact there are guides to hold the straps.
Front and rear tie-downs…
– Last Updated: Jun-21-12 1:37 PM EST –
... help very little in stabilizing a canoe against lateral wind forces on most cars. You need to be able to align those tie-downs so that they are fairly closely in-line with the direction of stress. Even in the situations with very good tie-down orientation, if you drive in strong winds the end of the boat can shift several inches before coming to a stop. On most cars, tie-downs end up being aligned about 60 or 80 degrees out-of-line with the direction of stress, and if you use just one tie-down on each end, the alignment will be far worse. With out-of-alignment tie-downs, even a tiny bit of stretch in the rope allows the end of the boat to move sideways quite a bit. If you drive in strong cross winds and don't have the canoe tightly anchored to the crossbars with gunwale blocks or equivalent method, you've seen this happen. With typical tie-down alignments, if you tried to make them so tight that they became effective enough to actually stop the boat from pivoting on the rack, you'd be pulling the ends of the boat downward with very extreme force. Thus, with typical end tie-downs, if the boat is well-secured to the crossbars, the crossbars still end up carrying most of the sideways wind loads, and if not, it shifts around on the rack. I've found that the very best way to tie a canoe so that it the front end doesn't shift sideways under wind load is with a pair of half-loops around the boat from each end of the front crossbar (on the average rack, you'd need to attach this rope to the crossbar mounting foot). That puts the ropes directly in-line with the direction of stress. It also does pretty much the same thing as gunwale blocks (other than putting the stress on the whole side of the hull instead of just the gunwale), which a lot of people use, and either way (half-loops of rope or gunwale blocks), it does nothing to relieve the stress applied to the crossbar mounts.
By the way, there's no need to "explain" the principle about front and rear tie-downs as backup support in case of rack failure. Ever seen one of my descriptions about how to do it so that even in the event of complete rack failure the tie-downs keep everything right where you want it? Again, the key is being mindful of the direction of applied stress on those ropes. Most people don't have the front and rear tie-downs acting in opposition, meaning that if the rack came loose from the roof, all sorts of extra slack would suddenly be available, meaning your load could move all over the roof, perhaps even slipping off the side. I also recently pointed out that Thule's pulley/hook combination is useless in that situation (What keeps that hook engaged once the rope goes slack? Not a thing.)
details details
Im not going to argue details.
You dont have to determine whether Thule instructions are “justified” or not. You are supposed to follow them.
The reason is best described by the following scenario. If somebody gets hurt by your boat after it flies off your car and you end up in court, their attorney is going to to ask you if you followed the installation instructions.
Now I am going to go out a limb a little and guess that “I didn’t follow them because Thule didn’t justify them” goes in the WRONG answer column.
Sorta missed the point
– Last Updated: Jun-21-12 7:05 PM EST –
It doesn't appear to me that you really understand the principle of why mounting the bars substantially farther apart, at least in the case of canoes with their large twisting moment in crosswinds, will reduce the stress on all mounting points by a factor of several times, or even that doing so is a desirable goal (the context of this includes your misunderstanding of end tie-down effectiveness, at least for average methods). Further, my point has nothing to do with liability, but rather what makes sense from an engineering standpoint. From that point of view, without any info from Thule, I'm trying to envision a logical explanation for mounting bars within about as little as 1/5th of the available roof-line length as they recommend for so many cars, and can't come up with one. It's not as if the roof-edge reinforcements don't run the full length of the roof, so what's the real reason? Back in the days when roofs had rain gutters, that little fold of metal had all the strength that was ever needed and then some, and people put their cross bars where they wanted to, often as far apart as roof length would allow. Modern cars have internal bracing along the roof edges which are plenty strong (this bracing is the framework for the door openings, and even to the rear of doors (like in a station wagon) it works as "truss support" for the entire car body) and Thule is not making use of what it can do, which is why I'm betting their recommendations have nothing to do with what works best for carrying boats.
I bet Slushpaddler is right. The answer is probably Lawyers. What's decided in a lawsuit can never be expected to stand up to logic, and if you ever get involved in such a thing you'll see what extraordinary lengths the plaintiff's lawyers routinely go to to eliminate every potential juror who's educational background or work experience makes it appear likely that they will understand what is going on (when the case is flimsy, the plaintiff's ideal juror is a person with no education whatsoever and a job that that requires minimal skills). By blindly enforcing a rule about rack mounts only being placed at junctions of support cross-members, Thule might hope to eliminate the opportunity for some some _____-head lawyer to win a huge settlement based on nothing but smoke and hot air. Yeah, I'm guessing again - trying to think of some reason that actually makes sense.