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Discussion Starter #1 (Edited)
Hey guys,

Now that we've got an enclosed trailer, we're going back and forth on how to secure it going down the road. My uncle suggested using the control arms to tie down from, but I immediately remember all the threads on not using them due to suspension damage.

Obviously the arms are connected to the fragile chassis, but are there any other specific reasons why we shouldn't use to tie from? I couldn't give any more specific answer other than "It will eff the car up if we use them." Help me out.

I went through all the past threads and found several "don't do it's"... but never any concrete reasons.
 

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I would not recommend using the control arms to tie down any vehicle. The company I work for manufactures control arms for OEMs and we have seen several failures resulting from cars being tied down via the control arms.
 

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Hey guys,

Now that we've got an enclosed trailer, we're going back and forth on how to secure it going down the road. My uncle suggested using the control arms to tie down from, but I immediately remember all the threads on not using them due to suspension damage.

Obviously the arms are connected to the fragile chassis, but are there any other specific reasons why we shouldn't use to tie from? I couldn't give any more specific answer other than "It will eff the car up if we use them." Help me out.
Yup, that about sums it up. Screwing up you chassis and/or suspension is all the reason you need to not do it. Run the straps through the wheels. Can't get any simpler than that.

Use towels or old t shirts or something over the straps where they contact the wheels to keep the wheel finish from being damaged.
 

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Yup, that about sums it up. Screwing up you chassis and/or suspension is all the reason you need to not do it. Run the straps through the wheels. Can't get any simpler than that.

Use towels or old t shirts or something over the straps where they contact the wheels to keep the wheel finish from being damaged.
+1 Strap down the wheels...
 

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Straps through the wheels is the ONLY way to tie down the Elise/Exige. Get a good set of straps and you can use towels or similar to protect the wheels, but I bought a set of fleece strap sleeves and found them to be much easier and not very expensive.
 

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Obviously the arms are connected to the fragile chassis, but are there any other specific reasons why we shouldn't use to tie from? I couldn't give any more specific answer other than "It will eff the car up if we use them." Help me out.

I went through all the past threads and found several "don't do it's"... but never any concrete reasons.
Specific reason: Tying down to the control arms can cause the control arms to bend. Even if the bend of the arm is very slight, it will create a stress concentration in the arm in the area of the bend. The arm can eventually fatigue and break with catastrophic results.
 

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what about using the strap assemblies for the two-wheel 'dollies' to tie the wheels down.
they're inexpensive on ebay last time i looked.
they form an upside down basket that cradles the top of the wheel.
if i were going to trailer one often, i'd use those.
sam
 

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what about using the strap assemblies for the two-wheel 'dollies' to tie the wheels down.
they're inexpensive on ebay last time i looked.
they form an upside down basket that cradles the top of the wheel.
if i were going to trailer one often, i'd use those.
sam

Why make it more complicated than it needs to be? Run the straps through the wheels.
 

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what about using the strap assemblies for the two-wheel 'dollies' to tie the wheels down.
they're inexpensive on ebay last time i looked.
they form an upside down basket that cradles the top of the wheel.
if i were going to trailer one often, i'd use those.
sam
In most cases, there just isn't enough clearance between the wheel and the bodywork for the ratchet on those "over the tire" straps to work. Through the wheel puts the ratchet away from the wheel and the body work so nothing gets scratched.
 

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I've see one Lotus shipped from Europe arrive with both rear upper arms bent from the straps.
The problem with using the wheel to strap the car down is that you put miles on the shocks as the car is transported - not much of a problem for short distances but worth considering when you ship the car 4500 miles to Mid Ohio and back.
 

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I see reference to tying the car down with straps through the wheels. Just to point out that that can be as bad as using the A-arms (maybe even worse as it provides a linger "level arm". If you are using the wheels to tie DOWN it's okay, but if you are using straps through the wheels that attach to the trailer some distance from the wheel (i.e. pulling the wheel forward or backward) then you are still loading the suspension mounts/chassis in ways that it is not intended.

The need is to tie the tire DOWN so that it can not more up or down, not back and forth (which happens naturally if it's tied down).

I would still prefer the wheel bonnets that strap over the tire and hold the tire down with straps in front and back of the tire pointing straight down. They make ones that have "remote" ratchets to allow the ratchet to clear the body work, like shown in the photo below:
 

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...I would still prefer the wheel bonnets that strap over the tire and hold the tire down with straps in front and back of the tire pointing straight down. They make ones that have "remote" ratchets to allow the ratchet to clear the body work.
the last time this came up (a few weeks ago) you mentioned this option. i've pondered it and decided that this is the solution i'm going to pursue when i actually find/purchase my enclosed trailer this Spring. it only requires the installation of four lengths of E-Track. :up:

it should secure the car to the trailer deck and also limit the possibility of damading the body with the strap hardware.
 

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+1 for the wheel bonnets.

They put almost no abnormal forces into the suspension and frame of the car and if used properly, will not damage the finish on the wheels or bodywork. I find they are much easier to use than regular straps through the wheels and hold the car much more securely onto the trailer.
 

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Discussion Starter #17
Thanks for the specifics everyone. Mac's wheel bonnets are the method I have wanted to go with since day one. My uncle, quite the muscle-car guy, just didn't understand why I couldn't use the A-Arms. Thank you for helping me enlighten him :up:
 

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I see reference to tying the car down with straps through the wheels. Just to point out that that can be as bad as using the A-arms (maybe even worse as it provides a linger "level arm". If you are using the wheels to tie DOWN it's okay, but if you are using straps through the wheels that attach to the trailer some distance from the wheel (i.e. pulling the wheel forward or backward) then you are still loading the suspension mounts/chassis in ways that it is not intended.
Rarely do I have a different opinion that Tim, but I do on this.

Maybee an engineer can figure this out but I figure the tiedowns through the wheels puts about the same force on the suspension as braking, accelerating and going over bumps in the road when I chock the tires. Crossing the straps in the back puts an abnormal load on the suspension in my opinion. I chock the front wheels in the front, the rear wheels in the back and I have boards screwd into the trailer next to the tires (inside on the fronts and outside in back) to keep the car from moving sideways (normal side load when driving the Lotus). I use the parking brake and car in neutral while towing. I tighten up the straps till there is no slack, then one rachet tighter. I depend on the chocks to keep the car from moving forward and back, not the straps. I depend on the trailer's and the car's suspension to keep the car from leaving the trailer in the up direction (and secondary is the straps). My trailer can't pull as many g's as the car can on the track (I hope). Just my opinion, make sure you consult an engineer with a P.E. , Lotus, an attorney and get a note from your boss before trying this yourself.
 

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Maybe an engineer can figure this out but I figure the tiedowns through the wheels puts about the same force on the suspension as braking, accelerating and going over bumps in the road when I chock the tires.
Normal loads on the suspension can rarely exceed 2,000 lbs of force (one G stopping of the entire weight of the car), and even if that was concentrated on one wheel, it would be spread across two A-arms and their mounts.

I can however, attach a ratchet tie-down strap and ratchet it tight, and easily exert 5-10,000 pounds of force on that one mounting point. and you need to pull it tight, because if you don't (due to the geometry), the car will not be held down onto the trailer. You would be surprised how easy it is to over tighten a ratcheting tie-down.

As another example, tow-trucks often pull cars up onto the tilted flat beds with winches attached to the A-arms of various cars. It is not unusually to bend something enough to require a wheel alignment simply from pulling a car onto the tow-truck.

Can you tie-down from the A-arms and not damage anything - sure, it's possible. But I'm not going to risk a bent chassis on my Elise by tying down on the A-arms when tire bonnets holding down will make sure there is no damage. :shrug:
 

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I will put my $.02 in here as a mechanical engineer in the automotive field with LOTS of trailering experience.

The point of using tie downs is twofold. First, and least important, is to keep the car in one place on the trailer. This can be done with the basket type, through the wheels, or around the control arms. Second, AND MOST IMPORTANT, is to keep the car from coming through the back window of your tow vehicle when you are involved in an accident. I am serious here. Any decent accident will rip right through some flimsy attachment system and your car will become a projectile intent on killing someone. At that point, you wont care about whether your suspension is bent or the wheels are scratched.

The ideal way is to attach to the frame and apply some amount of criss crossing to the straps to provide lateral support. Using the frame keeps the car from bouncing. Remember that the rear straps protect in a front-on collision and they should be mostly straight to maximize their strength in that direction.

Of course, the above plan wont work well on the Elise because of the frame design. I dont like the basket/net styles because they require the use of E-track which many people dont use and do little to constrain small movements. When the car starts moving on the trailer in an accident, it takes a lot of effort to stop it again. If the restraint lets it move even an inch, that just means it is more difficult to stop. Due to the angles of the webbing, the basket styles are best at holding the tire down, not fore/aft or lateral.

Personally, I would go through the wheels. The suspension is designed to withstand LOTS of force before it breaks. If you manage to break the suspension or frame you should be more concerned that you just had a major accident rather than what happened to a control arm or two. That said, dont go wailing on the ratchet straps when connected to the wheels. You are loading the suspension statically and can easily create a lot of force that is unnecessary. Just make them snug.

One note of caution about going through the wheels. THE WEBBING MUST POINT TO THE CENTER OF THE WHEEL WHEN VIEWED FROM THE SIDE. If you have the webbing mounted too low or too high, it will eventually rotate the the tire and the webbing will become loose. I have seen this happen many times.

I like the idea of using boards attached to the top of the trailer to constrain the car. This wont keep the car on the trailer in an accident, but it will do wonders towards keeping the car still.

If I were to trailer my car often, I would make special tabs on the chassis to mount the ratchet straps to. That way, you are more secure and it is easier to hook up. I did that on my race car and I could hook it up in about 30 seconds. Granted, this wont be easy on the Elise, but I am sure it can be done.
 
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