Car speed with roof rack^

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Carbon
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Car speed with roof rack^

Post by Carbon » Sat Feb 27, 2010 8:34 pm

Just wondering what sort of speed you Guys travel at when you have the Kayak (s) on top of the car.

Thinking about motorway cruising speeds, when not stuck in roadworks or specs cameras !.

Also do you always tie down front and rear.

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Douglas Wilcox
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Re: Car speed with roof rack

Post by Douglas Wilcox » Sat Feb 27, 2010 9:02 pm

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Never more than 40mph M'Lud. Wot's a tie down? Is it an extra?

Douglas

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MikeB
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Re: Car speed with roof rack

Post by MikeB » Sat Feb 27, 2010 9:16 pm

As above!

Although I have used front and rear ties with a double and two singles on!

Dave28
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Re: Car speed with roof rack

Post by Dave28 » Sat Feb 27, 2010 9:25 pm

60 to 70 on mway (how else do you move a sea kayak from Sutherland to Plymouth?) but only one boat, and with both front and back tie downs.

mick m
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Re: Car speed with roof rack

Post by mick m » Sat Feb 27, 2010 10:42 pm

Iv seen the damage don to a car with modern roof racks after a truck past it at speed with2 boats on it , it pealed the bars of the roof and damaged the boats, sins then I always yous a light spectra cord to tie the frunt down to stop the wind lift, the light spectra is strong , and dosent impear my vision to much

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Erling
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Re: Car speed with roof rack

Post by Erling » Sat Feb 27, 2010 11:10 pm

Across Sweden last summer; 100 - 120 kmh. Tie downs for peace of mind. Bikes strapped and zip-tied to the rear-mounted bike rack. Everything felt rock solid.

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chrism
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Re: Car speed with roof rack

Post by chrism » Sun Feb 28, 2010 1:42 am

Up to 70 on the motorway with these two boats on my car
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(though my car's a bit bigger than that one).

No endlines used, but long racing style V-bars (as you can see in the picture), which give rather more boat support than just tieing on to bars. Did end up having to tighten the roofrails back onto my roof for the trip home after they got a bit loose on a trip up to Fort William!

sprintpaddler
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Re: Car speed with roof rack

Post by sprintpaddler » Sun Feb 28, 2010 2:21 am

Hi Carbon,
Any speed you choose, but as a trucker & someone who`s done a few journeys with a 17 ft kayak I wouldn`t venture anywhere without front & rear tie-downs. There`s a lot of force on a small area of the boat just tying it down to the roof rack, let alone the forces that are applied when you get even small up & down movements at each end, so if you can cut down that movement with lightly applied braceing fore & aft so much the better. Another thing to consider, & most don`t, but in the event of an accident that extra braceing can mean the difference between keeping the kayak in the vacinity of the car or it shooting off like a missile! ( I`m not considering damage to the boat, but to people!! ) Another thing to note is a cockpit cover is a good idea, as it will be beneficial for MPG without all that air shooting in. I lose about 3-5 MPG hauling my boat around depending on conditions as it is, so anything you can do to improve it is worth doing.

Now go & get those tie-downs, & good hauling!
Cheers, Ted.

robyakmo
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Re: Car speed with roof rack

Post by robyakmo » Sun Feb 28, 2010 7:34 am

I was once Driving up the M6 in the 2nd lane and came across 2 kayaks still attached to a roof rack
Further up the road there was a guy running down the hard shoulder with a worried look on his face

I’ve used front and rear ties since then

Carbon
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Re: Car speed with roof rack

Post by Carbon » Sun Feb 28, 2010 8:50 am

Thanks for the replies. I travel at aprrox 65 on motorways and always use lines front and rear, and wondered if it was overkill, from the replies it would seem not. I use tent guy line material for the lines complete with adjusters, quick and easy to tension, and have never moved.
Douglas Wilcox wrote:
Never more than 40mph M'Lud.

Douglas
May I remind you Mr Douglas that you are under oath, I put it to you that you were traveling at 45mph...............

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Douglas Wilcox
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Re: Car speed with roof rack

Post by Douglas Wilcox » Sun Feb 28, 2010 9:51 am

One of the worst loads on sea kayaks on a roof rack is the sideways blast caused by the bow wave of a large truck coming the other way on a single carriage way road. Unfortunately a bow tie down provides little mechanical advantage to resist this. The best answer is to have as secure a roof rack as possible and to drive at a speed that is within a sensible range for how secure your roof rack is, whether that is 40 or 70 and remember to slow down if it is a windy day. My friend Jim has a very nice Peugeot estate with roof rails and J bars. The kayaks bounce around all over the place because of the flexibility in the roof rails and Jim uses tie downs. I am lucky enough to be able to afford a BMW which has a very well designed roof rack. It is totally rigid and bolts down directly into recesses in the roof with stainless steel bolts. It even comes with a torque wrench to make sure the bolts are done up correctly. Using J bars to secure the kayaks, if I grab the bow and attempt to move it, the whole car moves (and BMWs don't have soft suspension).You also need to make sure you do not exceed the roof load of the car, in my case 75kg. The three kayaks I usually move weigh 70kg so I never put anything in the hatches. I also like to use hatch covers.

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However, if I go somewhere there is plenty of parking and I am not using a ferry, I prefer to use my trailer.

Douglas

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MikeB
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Re: Car speed with roof rack

Post by MikeB » Sun Feb 28, 2010 12:34 pm

Douglas Wilcox wrote:The best answer is to have as secure a roof rack as possible and to drive at a speed that is within a sensible range for how secure your roof rack is, whether that is 40 or 70 and remember to slow down if it is a windy day. My friend Jim has a very nice Peugeot estate with roof rails and J bars. The kayaks bounce around all over the place because of the flexibility in the roof rails and Jim uses tie downs. I am lucky enough to be able to afford a BMW which has a very well designed roof rack. It is totally rigid and bolts down directly into recesses in the roof with stainless steel bolts. It even comes with a torque wrench to make sure the bolts are done up correctly. Using J bars to secure the kayaks, if I grab the bow and attempt to move it, the whole car moves (and BMWs don't have soft suspension).
Indeed so - therein lies the problem. Not all cars and roofrack systems are equal. I've even heard tell that Peugeot roof rails are not really intended to carry a load on!

We had a little debate on this subject some time back, notably with regard to racking systems, and associated tie downs. Well worth a look at.

Mike.

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gasserra
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Re: Car speed with roof rack^

Post by gasserra » Sun Feb 28, 2010 5:55 pm

Here are a few considerations:

Racks are designed to withstand/support a downward force (weight). They resist an upward force (lift) a lot less well.

A rockered boat, especially one with any flare in the bow, will generate lift from the air pressure on the hull when driven forward.

The longer the overhand, the greater the force to which the forward crossbar of the rack will be subjected—the boat’s overhang is a long lever arm.

The failure will be abrupt and catastrophic—the kayak/car equivalent of popping the pull tab on a beer can. The April 2010 Sea Kayaker magazine includes some excellent photos of the aftermath.

A taut bowline provides effective counterforce against that lift.

I’ve driven many thousands of miles at US interstate speeds (70mph/115 kph) with long boats (eg Nordkapps) and no problem—but always well secured fore & aft as well as to the crossbars.

The Shark
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Re: Car speed with roof rack^

Post by The Shark » Sun Feb 28, 2010 6:16 pm

I've sat in a car doing a ton with two Plastic Aquanauts on the roof somewhere in Dorset. Name and VRN witheld!!

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Douglas Wilcox
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Re: Car speed with roof rack^

Post by Douglas Wilcox » Sun Feb 28, 2010 6:31 pm

I started with V bars, with the kayaks sitting right way up, I did not like the lifting force, even if you have a tie down, it still affects the car's steering. So I moved them to my trailer, where the cross bars are much further apart than on a roof rack and the boats sit in the car's slipstream. Ireplaced them with J bars and I have found they generate much less lift on a car roof.

You might get an idea of what I mean by comparing Erling's car with my car. I have now done over 60,000 miles with kayaks on J bars. I like them a lot.

Douglas

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JB-NL
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Re: Car speed with roof rack

Post by JB-NL » Sun Feb 28, 2010 7:00 pm

Indeed so - therein lies the problem. Not all cars and roofrack systems are equal. I've even heard tell that Peugeot roof rails are not really intended to carry a load on!
Same experience with a Peugeot 406 break I drove. Before we reached the ferry in Rotterdam to the Uk on our way to Wales, the rack was bent. The manual stated max load 100 kg!! We only carried 3 kayaks and travelled at 90-10 km/hour.
Never a French car again....
With my VW camper-van I carry max 2 kayaks on a reinforced glass fiber roof, stands 9Bf last year ( but as mentioned previous) with adjusted speed.
To support the roof I tie the front.
With my Corolla I don't tie them down.

Good luck

JB
--==Never go faster than your Angel can fly==--

GEOFF S
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Re: Car speed with roof rack^

Post by GEOFF S » Sun Feb 28, 2010 7:10 pm

On the subject of roof racks..
any recommendations for diy roof racks for hire cars ? I'm thinking pipe insulation and several straps through the doors/windows but I'm sure somebody has done something better.
will be wanting to transport wave ski on hire car in Morrocco.

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MikeB
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Re: Car speed with roof rack^

Post by MikeB » Sun Feb 28, 2010 7:57 pm

GEOFF S wrote: any recommendations for diy roof racks for hire cars ?
Some thoughts here which may help.

John N
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Re: Car speed with roof rack^

Post by John N » Sun Feb 28, 2010 8:51 pm

I use THULE bars on an old VOLVO 940 estate. On this I can place the roofbars some distance apart - I usually place them at around 4'6". My boat sits in THULE 'J' cradles. I'll sometimes carry up to two other boats on the other side - club easky 15' boats top and tailed against a standard upright. I feel quite happy (apart from the fuel consumpstion) doing 75 indicated on the motorway with this arrangement.
When adding up weights for your roof loading on the vehicle don't forget to include the weight of the bars and fittings.
That's a good thought from Gassera - I'd never thought about the lift generated by the boats before.

M-J-B
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Re: Car speed with roof rack^

Post by M-J-B » Sun Feb 28, 2010 9:15 pm

Back in the days when I drove a classic Saab 900 I could easily drive 140km/h with my Nordkapp strapped to the Thule roof rack. The rain gutters on the 900 allowed me to mount the racks far apart and the cradles were bent to match the shape of the kayak hull. Everything was solid without extra tie downs.

Nowadays I drive a Saab 9-3SS that uses a similar recessed bolt-on rack mounting system as BMW (and others) use. The distance between the racks is less than what it was on the 900 and anything in excess of 120km/h makes me uncomfortable even if I use single tie downs front and back. Windy days I drive slower. On a calm day without extra tie downs I rarely drive over 80km/h. I have my doubts that the bolt-on mounting system will stand the test of time. The racks are frequently mounted and unmounted and I'm afraid the threads will some day corrode and strip from the car roof. I use Thule racks and Thule kayak cradles that actually seem even more solid than the older pre-bent cradles I used to have but they should be further apart. I'm considering mounting custom made anchor points under the bonnet and boot lid allowing easy, fast and secure use of double extra tie downs front and back.

chrism
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Re: Car speed with roof rack

Post by chrism » Sun Feb 28, 2010 10:18 pm

JB-NL wrote:
Indeed so - therein lies the problem. Not all cars and roofrack systems are equal. I've even heard tell that Peugeot roof rails are not really intended to carry a load on!
Same experience with a Peugeot 406 break I drove. Before we reached the ferry in Rotterdam to the Uk on our way to Wales, the rack was bent.
Maybe that explains why I had to tighten the rails on my 406. Not bent them though, despite a very long and heavy load (longer than most on here would carry - if not heavier, as those doubles weigh a lot less than you'd expect). Removing the roof lining and tightening all the bolts on the inside does help a lot though!

Seadog
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if you don't mind the fuel economy

Post by Seadog » Mon Mar 01, 2010 11:44 am

Subaru Forrester - heavy duty roof rails with integral tie down slots front and back at good distance appart. I.e. the tie down straps are attached to the roof rails and do not rely on the strength of the roof bar fixtures. I also tied down front and back for motorways. In addition of long journeys.

Not sure if the current model has the same roof rail arrangment (I don't do new cars)

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Jim
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Re: Car speed with roof rack^

Post by Jim » Mon Mar 01, 2010 4:04 pm

Lots of different forces and only 4 often quite flimsy attachment points.

I always tend to use tie downs front and back for sea kayaks, the wind that is diverted up the windscreen must be buffetting upwards, although if they stay in place squeezing it through the narrow gap will create a low pressure sucking them down? Ooooh now i'm thinking too hard! Important point with tie downs is not haul on them until you get a musical note (as you should with the main straps at the bars), because this itself might be enough to break your boat, but equally you do need to remove the slack so that you don't end up shock loading the rope (could break it especially at the knots) if you have to brake hard and the boats slip under the main straps (seen it several times with river boats, which usually aren't tied down at the ends). A slightly stretchy rope is ideal for this because you can feel when you have it just tight enough and leaving a bit of the stretch to damp shock loads is also useful. The only problem is that with a thick rope it can look a bit saggy when it is actually tight enough so you have to work on developing the feel.

Definitely well worth investing in good roof racks if you are going to be carrying kayaks a lot - often the manufacturers are hopeless and somthing like a Thule is essential. Mostly built in longitudinals are a good idea because you can get some heavy duty 3rd party systems to clamp onto them, but do be careful, I have seen older cars where the built in rails moved in the roof, and others that are made of fairly thin tube in the first place.

DIY roof rack for hire cars?
Several approaches, most for low speed short journeys only:
* Inflatable roof rack - I've heard stories of people driving to the alps with them, but also stories of them bursting..... I wouldn't trust them!
* Karrimat on the roof (or pipe insulation) and strap through the doors. this works we did it from the Airport to a friends place in California but it has limitations: the straps will cut accross where you want to put your head, you will dent the roof of the hire car (it will pop out but may leave a crease), it looks dodgy as hell and is likely to get you pulled over.
* Plan your hire car and insist on getting the model you booked when you arrive. Buy a decent Thule or similar Rack system and the correct tower/feet combination for the car you are hiring and take it with you. Alternatively buy the common parts and gamble on being able to buy the correct foot kit when you get there and find out what car you are getting. Having got our boats to the friends house we drove to a well known outlet and bought Yakima towers and feet to fit the hire car and borrowed our mates Yakima cross bars for the 2 week trip. Actually the system wasn't a great fit on the car in question so we returned the towers and feet at the next opportunity (which happened to be the end of the trip) and got a refund.
* If you can get a car with built in longitudinal rails and can do a square lashing all you need is some rope and timber, although U-bolts and steel cross bars will be better.
Of course all the above assumes that the hire company insurance is valid with a load on the roof, and in our case for unpaved roads. Always check the small print after the trip.

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Andee B
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Re: Car speed with roof rack^

Post by Andee B » Mon Mar 01, 2010 6:24 pm

Not sea kayaks, but mine will quite happily sit at 80mph on moterway runs. Although it does take a while to get there!
DIY is the way to go :)


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chrism
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Re: Car speed with roof rack^

Post by chrism » Mon Mar 01, 2010 8:41 pm

Andee B wrote:Not sea kayaks, but mine will quite happily sit at 80mph on moterway runs.
Well if you're talking "not sea kayaks" then I've been in a car doing 100mph with 4 boats on normal roof bars. Competition polo boats, so probably a tad longer than those. Before anybody complains, this was on a trip to a polo tournament in Gottingen.

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wilsoj2
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Re: Car speed with roof rack^

Post by wilsoj2 » Mon Mar 01, 2010 9:20 pm

We travel at highway speeds (55-70mph) with boats on our cars on racks. Each boat is strapped down to the rack fore and aft of the cockpit. Each has a bow line to make it easy to spot if there is any worrisome movement.

After using saddles for a bit, we've gone back to using stackers as we can carry up to 4 boats at a time. We've carried 4 sea kayaks or 4 ww boats or a mixture of sea and ww kayaks.

Currently our two vehicles are a 2008 Subaru Outback wagon and a 2003 Mercury Sable wagon.

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Re: Car speed with roof rack^

Post by Rdscott » Mon Mar 01, 2010 9:26 pm

I've hit speeds i shouldn't have

With 3 sea kayaks on the roof of an astra the fule consumption isnt good around 35mpg but doing 85 to 90 i might as well have hole in my tank.

Carbon
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Re: Car speed with roof rack^

Post by Carbon » Mon Mar 01, 2010 9:36 pm

Nearly 700 views in just over 2 days, seems lots of interest and views on this subject !!!!!!!!!!!
For the record, I use Thule bars and Thule J bars, sitting directly on Audi A4 avant roof rails (rock solid) use tie downs front and rear, these are attatched to towing eye bolts (the ones that are normally in the boot with the spare wheel ), they are inserted through the bumpers and screwed into place when the blanking plugs are removed.
Thanks for the replies
Steve

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MikeB
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Re: Car speed with roof rack^

Post by MikeB » Tue Mar 02, 2010 10:11 am

Carbon wrote:Nearly 700 views in just over 2 days, seems lots of interest and views on this subject !!!!!!!!!!!
For the record, I use Thule bars and Thule J bars, sitting directly on Audi A4 avant roof rails (rock solid)
I've used an identical arrangement on an A4 and an A6 - the only comment I'd make is that while the Audi rails are excellent, and so are the Thule bars, any system is only as good as the weakest link in it, and if you strip the Thule feet / clamps, you find that the whole thing depends on a bit of bent metal to lock it down.

While that's common to all such systems - and Thule is excellent kit - everything still depends on a bit of bent metal!

That said, I've never experienced any problems with the set up, and even these days when it's on an old Mondeo, it's still excellent and as I mentioned previously, I seldom use ties.

On the subject of ties, I've found that using black deck line at the front is by far the least obtrusive visually. I never tie it "tight" though, it's necessary to have a little play to allow the boats and cradles to flex.

tommfuller
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Re: Car speed with roof rack^

Post by tommfuller » Tue Mar 02, 2010 11:40 am

I use two pairs of J bars on a Subaru rack (which I think is made by Thule) which clamps to the roof rails. It's very solid and I never use front / rear tie downs. Has been tested at rather high speeds...

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Cheers,

Tom.

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