Can tow bolt holes be used for trailer hitch

[smark]

Originally Posted by mweaver

Can the tow bolt holes in a 451 be used for a trailer hitch? Since their purpose is to be able to tow the car backwards, it only seems reasonable that bolts screwed into them would be strong enough to pull a trailer that would be substantially lighter than the car itself. Has anyone tried this? Does anyone manufacture such a product? It just seems it would be a simpler solution than the expensive hitches that bolt to the frame and require drilling holes in it. I've seen various ss bolts that fit the holes for sale. One had a hex top on it that if the hitch was cut to fit it, the bolt would not be able to unscrew itself.

That's not is safe. You could shear off a tow bolt. You need to read you owners manuel. Its says do NOT TOW anything with this car. (I know they make hitches for it.) For bike racks. Go to the UHaul site.

[sunnyokanagan]

Are the towing eye bolt threads on the 451 the same as the 450, i.e. Acme thread? The Acme thread is designed not to bind or seize, so that it will easily come undone once the temporary use is over.

For this reason, I would again suggest that this bolt system not be used for the purposes described in this thread. Even if you torque it up "tight", it will come loose due to its special thread angle, seat, and shoulder - that's what this special configuration thread is for, and why I expect it was chosen by the engineers for this temporary towing eye application. It is easy to start the thread, fairly tolerant to minor grit etc., and easily removed without applying loads of torque.

[donnyonee]

i wouldnt use the tow holes for that.

[dingos]

DON'T!! I know what will happen!! The tow bolt's are welded into the bumper support and not that good at that! They will rip out! Trust me, I'm getting a new Garage built bumper support, made so I can use the set-up I have on my Smart.

I am carring a SKB 50x20 Double golf case with about 70lbs in it (tools) and they were ripped out in less than a week. Welded them back up for a short term fix untill I can get into the shop and tear it down to rebuild. I'll Doc the build when it happens next week.

[jetfuel]

...hey dingo...where did the brake occurred?

jetfuel

[dingos]

On the left side (driver side) It cracked from the 9 o'clock to 3 o'clock position and bent down and out, The right side one ripped, not a crack RIPPED from about 2 o'clock to 9 o'clock than went at a 45* angle for about two inches!

Once we took the back end off, and saw what we saw, We did a Half Arse job, and welded up the tow support, This is just a temporary fix, should be able to get back into my buddy's shop on wednesday and take everything off and build my own bumper support out of 1-1/4 Sq tube.

The support already had a 1/4' plate welded to the back of it. That worked great for the Hitch that was built. to stop any flex, but for the tow support's it didn't help. They aint made for weight on top of them. A bike no problem! anything over 50lbs I wouldn't. Unless you reinforce it some how.

[jetfuel]

...thanks for the info...the reason I asked was 'cause while at the center the other day for the 2.0 update I took a good look at how the tow hook was placed in the frame just because of this thread ...the threaded portion is a 2" long boss welded all the way around the long plate that is the bumper itself, the bumper is then welded to a square base in all points of contacts...close inspection of the welds revealed a very good job of penetration even though that it was not all the way around but 2" long with open spaces in between....my first thought was it was strong enough to pull whatever you wanted to....the weakest link here...the threads....there are but 5 threads inside the boss...

jetfuel

[Prison city smart]

On this site theres a tow bar setup for sale in the for sale market place to tow your smart behind another vehicle using the tow bolt holes. If you can tow the smart with the bolt holes you should be able to tow a small trailer with the rear bolt holes. ???????????????????? I have the car and I have the trailer but not a hitch. Doesn't seem to be anything to fit a brabus.

[ExonicJay]

Here is a picture that shows the tow threaded holes inside of the mounting flanges.



The threaded holes are acme threads with few threads.
I would recommend beefing up the threaded hole for hitch use.
Also stiffing the internal bumper from torsion loads (twisting) would be a good idea too.

The next weakest point is the 6 torx headed bolts that hold the internal bumper flanges to the Smart's frame.



For more details on my hitch installation see:
http://www.smartcarofamerica.com/forums/f4/advantages-having-smart-hitch-28741/
or
http://www.smartcarofamerica.com/forums/f19/installation-2-hitch-bike-rack-pictures-3588/index6.html