Magnets To Attach Ski Rack To Car Top? - Page 2 - diyAudio
Go Back   Home > Forums > General Interest > Everything Else
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 26th September 2006, 03:59 AM   #11
diyAudio Member
I_Forgot's Avatar
Join Date: Jan 2005
Location: Phoenix, Az.
Originally posted by kelticwizard
It might be that rare earth magnets might be the way to go here.
Don't forget to put one arm out the window to help hold the stuff down...

  Reply With Quote
Old 26th September 2006, 04:33 AM   #12
Wizard of Kelts
diyAudio Moderator Emeritus
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
You have no sense of adventure at all, IF.
"A friend will help you move. A really good friend will help you move a body."
  Reply With Quote
Old 26th September 2006, 05:55 AM   #13
diyAudio Member
Join Date: Apr 2003
Location: Portland,Oregon
Blog Entries: 4
Send a message via AIM to DigitalJunkie
There are some *seriously* strong magnets around..
I'd bet some could hold an elephant on to the roof of your car! Really!

First,Be warned: you *MUST* be careful when handling them,you can easily remove fingers if you get "pinched" with them
They can come together with tremendous force.
Be very careful when installing/removing your rack!

The guys that make DIY wind-power and such use big strong magnets alot in thier generators,so if you know where to look,you can find quite strong magnets.
Here's some..

Or,Maybe find a few of those magnetic handles used for carrying big metal plates,etc. Those puppies are pretty strong too. Kinda large though.
  Reply With Quote
Old 26th September 2006, 12:29 PM   #14
Schaef is offline Schaef  United States
diyAudio Member
Join Date: Jan 2001
Location: Cuyahoga Falls, OH
There are a couple of things to consider with your idea KelticWizard. All of them point to don't.

First, with a lot of magnets, their force is in holding them together, which means pulling them apart is diificult, but you can slide them apart. Now, in your application, what direction are the main forces going to be in? Perpendicular to the magnet, meaning, while it will hold the roof rack down, it won't hold it in place. Particularly if you put felt in there to protect your roof.

Second, in addition to the strength of the magnet, you also need to consider the roof itself. There may not be enough metal in the roof to be able to hold the magnet well. I found out about this by watching a Mythbusters episode where they had magnets that worked great on 1/4" steel but on 1/32" sheetmetal ducting, they couldn't hold.

Third, if you're going to use the very powerful magnets others have pointed to, have you thought about what its going to do to the contents INSIDE the car?

Finally, the magnets you talked about have nowhere enough strength to do the job.

Oh, and just as a quick real life example. I did a theatrical show where the director wanted a bulletin board that could be attached and removed from a wall without any visible means of support. My final solution was to use two old hard drive magnets behind the flat and two mending plates glued to the back of the board. It took both magnets to hold the 2 pound board on the wall, otherwise it would slide. (Hence my comments on #1) Oh, and these magnets were out of full height 5 1/4" hard drives and could hold each other through my hand, so they're strong.

So, short answer, I agree with I_Forgot, let me know your plate # so I can avoid you if you do this.
  Reply With Quote
Old 26th September 2006, 12:47 PM   #15
Wizard of Kelts
diyAudio Moderator Emeritus
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State

Thank you for your well thought out comments. However, I find myself getting committed, (you can interpret that last sentence any way you want ).

Digital Junkie made a good post pointing me to those lifting magnets. Available inexpensively, they are ranked at 25 lb, 50 lb and 100 lbs lifting weight. Each crossmember will have two, so you double that.

Of course, the roof is slightly curved, so the I imagine the lifting power is reduced somewhat since it won't be contacting a completely flat surface. And there will be thin coating of something, (rubber, fabric) to weaken it slightly more. Still, I think there will be more than sufficient force here.

By the way, if someone has a suggestion of a nice sticky coating to put on the bottom of these magnets so they won't scrach the paint, by all means please jump in.
"A friend will help you move. A really good friend will help you move a body."
  Reply With Quote
Old 26th September 2006, 12:55 PM   #16
diyAudio Moderator
pinkmouse's Avatar
Join Date: Apr 2002
Location: Rotherham, England
Just a quick point, in the UK roof racks have to be approved for use, so if something goes wrong you are insured. If your idea fails and damage or injury occurs, then you might well find your insurance doesn't cover you...
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 26th September 2006, 01:01 PM   #17
Wizard of Kelts
diyAudio Moderator Emeritus
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
On the issue Schaef raised, the matter of the the rack sliding across the top of car. Let me relate something that actually happened a couple of years ago, when I was using the car which the hooks of the roof rack had something to hook onto-thereby making a completely secure system.

Once I accidentally put an 8 ft stepladder on top of the racks without lashing it down. It was just resting on the racks entirely unsecured.

I drove off. For about half a mile, there was a gentle downward slope. I stopped at the stop sign. Made a right turn, drove off at around 35 or 40 mph.

It was only about a mile down that road that the unsecured ladder fell off the racks. I picked up the ladder, secured it and drove off none the worse for wear.

Granted, there was no wind. Granted, this was not highway speeds. But the fact that the ladder stayed on the roof, unsecured for a mile and half of normal driving indicates to me that if the racks are being held to roof by two lifting magnets of 50 lbs lift each, sliding across the roof is not likely to be a problem.

Of course, once I do this, I have every intention of going onto an empty road and driving this around, slamming on my brakes, etc, to make sure this thing works before I get onto any other roads with traffic on them.
"A friend will help you move. A really good friend will help you move a body."
  Reply With Quote
Old 26th September 2006, 04:24 PM   #18
diyAudio Member
SmarmyDog's Avatar
Join Date: Jul 2003
Location: San Diego, CA
I have every intention of going onto an empty road and driving around, slamming on my brakes
I've always wondered what folks do in “The NUTmeg State” for fun.
  Reply With Quote
Old 26th September 2006, 04:44 PM   #19
wwood is offline wwood  United States
diyAudio Member
Join Date: Nov 2001
Location: Minnesota
As mentioned previously, the holding force of the magnets is perpendicular to the face of the magnet. Friction is what keeps it from moving laterally. If your roof and the magnets have a large coefficient of friction then it might work. I have some neodymium - iron boron magnets (about as strong as they get) and they slide over finished steel quite easily. Stopping or turning sounds like a big risk, plus damage to the finish of your vehicle.

If you must do this, make sure the magnets have a large surface area, the larger the better, then roughen the mating surfaces to further maximize friction.

What did you say your plate number is?

  Reply With Quote
Old 26th September 2006, 05:04 PM   #20
diyAudio Member
Join Date: Oct 2002
Location: Munich, Germany
Magnetic ski racks are not new. They do have approval by the German authorities (TÜV - not easy to deal with).
I give you one link. It is in German but a translation programme will give you the essence:


One more link to an Italian manufacturer:
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to attach photos g(f(e)) Tubes / Valves 2 9th March 2008 12:36 AM
Can't attach Photo's c2cthomas Forum Problems 3 13th May 2007 12:29 PM
Attach driver magnets to metal frames? Yes, no? talatnat Multi-Way 0 26th May 2006 02:34 PM
Can't attach jpg image - Help ralph-bway Everything Else 4 14th January 2005 07:05 PM

New To Site? Need Help?

All times are GMT. The time now is 09:49 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2