Hitch for CT

OZ-CT200H said:

Install manual states 200lbs (~95Kgs) tongue weight.
I am assuming this is the total weight that the bike rack, bikes, and all accessories fitted?

It also states not to exceed your car recommended tow capacity which for CT is 0 and not recommended. How can these guys sell a product that goes against manufacturer's recommendation and they try and cover their own *** saying don't do it? Makes no freaking sense.

I want to get something like this as I prefer it to the roof mounted racks as they look plain ugly on the CT, but this sort of cover your *** disclosures don't inspire any confidence.

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Typically the tongue weight on a class I hitch should be 1/10 of maximum towing for class I which is 2,000 pounds. The gravity weight on a class I hitch should not exceed 200 lbs. You will be completely okay with your bikes; However rewarding yourself with a new sub 20 lbs. bike would be awesome.

As far as a CT not recommending towing, as with everything you can take that with a grain of salt. The maximum load recommended for the CT is 825 Lbs. (see page 650 of your owner's manual) this includes the weight of all passengers plus any cargo.

So you if your weight plus the weight of the hitch and the bikes and any other passengers and luggage is less than 825 lbs., you are good to go.

There are going to be owners who load the car with 4 people and cargo that will exceed the 825 lbs. without a hitch or bike rack.

TAZII said:

Any time I look at a used car with a hitch receiver I move on to another one without the same. Towing and using a hitch for other accessories puts a lot of stress on the vehicle. The engine and transmission have to work significantly harder and the brakes and suspension take more abuse. Even a light weight utility trailer without a load puts a great strain on the vehicle. A bike rack induces a pretty significant moment arm load on the vehicle's under carriage and structure. I think all of these reasons are why the car manufacturer does not recommend using it with a hitch. It'll definitely work for you but be advised you're asking for trouble and will likely take a hit at time of trade-in.

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Interesting...

However.. One can self-install this Curt hitch, self-remove it and restore to like original...

Could you please explain "moment arm load" on the undercarriage/structure, and why it is detrimental? (as related to the 200 lb limit of the hitch)

Also.. I can't comment on pulling a trailer, because that could be such a variable... but do you think 200 lbs on the back of the CT (as a hitch, rack and bikes) causes any more stress on the engine than if that weight was in the rear seat or rear storage area? Assuming one does not overload the rest of the CT...

Would love to hear your comments.

Thanks.. R

kalo925 said:

Interesting...

However.. One can self-install this Curt hitch, self-remove it and restore to like original...

Could you please explain "moment arm load" on the undercarriage/structure, and why it is detrimental? (as related to the 200 lb limit of the hitch)

Also.. I can't comment on pulling a trailer, because that could be such a variable... but do you think 200 lbs on the back of the CT (as a hitch, rack and bikes) causes any more stress on the engine than if that weight was in the rear seat or rear storage area? Assuming one does not overload the rest of the CT...

Would love to hear your comments.

Thanks.. R

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Kalo925,

A bike rack does not put signifcant stress on the carriage and frame. Neither does a light utility trailer. I have a light wieght boat I can move it by habd and the tongue wight is probably only about 30-40 lbs.

Momment arm load is a physics term and albeit it was used somewhat out of context , but here is a simple explanation.

If you have a lever 10 feet long and you move it 1 foot with 10 lbs force then the momment arm torque is 100 ft-lbs. The fulcrum point only moves slightly when you move the end of the lever a foot. This is simliar too and why a socket wrench allows you to tighten nuts far tighter than by hand. Obviously the force at the fulcrum is much greater than the force you extert at the end point. So 200 lbs save four fout out on a Curtis hitch could potentailly exert 800 ft-lbs toque on the carriage frame which is rate at 825 lbs of human/cargo weight limit.

I would not worry about 200 lbs of bicycle weight ( even though that sounds a tad heavy), nor would I worry about pulling a light utility trailer.

However, if you are going to push the limits of a class I hitch ( tongue weight 200 lbs, load weight 2,000 lbs) then maybe the CT is not the right car for you.

One other subtle point, the CT has MG2 which can act like a motor or genrator. In motor mode , it can provide 153 ft-lbs of nearly instant torque, which actuall puts a CT owner in better postion than most 4-cylinder gas engine only owners.

Regarding moment arm load, the bike rack does apply. The center of mass of the bikes is a certain distance away from the hitch. The force exerted on the tongue is the mass times the distance away. A trailer is different because it has its own axle and wheels to help balance and distribute the load. When properly loaded a trailer's weight at the tongue can be minimal in comparison to the total weight loaded into the trailer. Once in motion a trailer's momentum can ease the burden on the car's drive train. A bike rack doesn't have this same benefit because there are no wheels to carry part of the load.

Most vehicles rated for towing have additional components like transmission fluid coolers and heavy duty suspensions that are all factors when determining towing capacity. It is not all about torque of the engine. True an electric motor has maximum torque at startup and an internal combustion engine doesn't, but that is not the only factor in determining towing capability. I bet your cooling fluids (which there are many on a hybrid) will run hotter when towing with the CT than they will normally.

Again, you will likely never encounter a problem with the bike rack under normal conditions. We all have different opinions on caring for a vehicle. I personally would not risk damage to such a nice car. That's why I have a Grand Cherokee to tow my boat, utility trailer, and bike rack.

Let's work this problem through a thought experiment. I'll present two scenarios and how it affects the engine, transmission, brakes, suspension, and structure of the vehicle.

Scenario 1: Putting 200lbs of weight in the trunk of the car (normal operations)
Scenario 2: Putting 200lbs of weight in on the hitch that is structurally connected to the frame of the car.

Scenario 1 is the no-brainer "very safe" scenario and scenario 2 is the one in questions. Now let's look at the difference between the two and we can conclude how scenario 2 affects the car.

Engine: Putting 200lb load on the car, regardless of where the load is placed (in the trunk, on the hitch, in the passenger seats) will require the engine to work just as hard to accelerate that mass forward.

Transmission: Transmitting power from the engine to the axle. The transmission would again have to work just as hard to regardless of where the load is placed.

Brakes: Convert kinetic energy into potential (battery) or heat (brake pads) will have to convert the same amount of extra energy from the extra 200lb regardless of where the load is placed.

Suspension: This is dependent on where the center of gravity of the vehicle is. 200lb in the trunk vs. 200lb on the hitch will have a slight difference in the center of gravity and ultimately how much load each suspension will have to carry. However, i don't believe this is would cause the rear suspension to wear immaturely.

Structure: There is a difference in terms of structures based on where the load is placed. Placing 200lbs on a hitch will cause a moment about where the hitch is mechanically fastened to the frame of the car whereas putting 200lbs in the trunk will not. However, I believe there is enough design margin of the frame of the car to absorb this. Think about it this way, if the frame of your car can withstand hitting a pothole going 65mph (maybe some rim damage), it should be able to withstand the load caused by the hitch.