Lexus CT200h Forums banner

61 - 79 of 79 Posts

·
Premium Member
Joined
·
875 Posts
:):)
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.
No offense, but it is obvious you are not an engineer. :rolleyes: I had a friend like you and he switched to business and actually did very well; had his own company. :)
 

·
Registered
Joined
·
391 Posts
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.
Kalo925,

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.
Thanks for these replies! Helps me understand it more quickly. I only plan on putting a couple bikes on for now. But pulling a small trailer on a rare occasion is something I want to understand more.

I recently pulled out my old Stumpjumper and have been riding up a local Mtn. It only has a front shock. :( The downhill isn't so hard, but still challenging for me. At 50 years now a full suspension bike is in order. (thinking less potential for crashing) The only problem is to get down to the Stumpjumper's weight of 25 lbs one has to look at a $6-7k carbon bike! I've never had a road bike and am looking at those too.. Might just pick up a couple of Treks. :)

are you s******* me? over thinking this way too much. A couple bikes on the hitch isn't going to stress anything with this car.
Thinking is not a sin! haha ;)
 

·
Registered
Joined
·
391 Posts
:):)

No offense, but it is obvious you are not an engineer. :rolleyes: I had a friend like you and he switched to business and actually did very well; had his own company. :)
I thought Nabby's response is quite good. Actually kind of what I was looking for from TAZII. Which points of Nabby's reply do you totally disagree with?
 

·
Registered
Joined
·
391 Posts
The CURT hitch is shipping on Amazon now. I signed up for the trial of Amazon Prime and can get free 2 day shipping for a month. Seems like a great deal to me...

Link below if you want to check it out.. R:)
 

·
Registered
Joined
·
63 Posts
I have Prime. It is a good deal if it is shipped by Amazon, but many things are not. 3rd party still charges. BUT, it looks like Curt is Prime.
 

·
Registered
Joined
·
28 Posts
Anyone have good pics of the Curt hitch installed (without the bike rack attached)? I want to see how much of it shows. Also, any problems with scraping it? Any problems with the weight of a couple of bikes and the rack?

EDIT: Read the thread more carefully and saw BostonGTR's pic and link to the Curt install instruction pictures, but still would like to see more member pics of the hitch and feedback. Thanks.
 

·
Registered
Joined
·
8 Posts
I'm a little late to this discussion but I thought I would add my .02 for future readers. I just bought my Lexus last week and I am going to put a hitch mount bike rack on after reading and looking at the following:

PLEASE NOTE if you decide to put a hitch rack on your car you are taking a risk and I will not be held responsible, nor should this post be take as doctrine. This is just how I came to the conclusion that it will be safe for my car.

- If you look in some of the overseas lexus catalogs they offer a "hitch mount" bike rack straight from Lexus. I did some digging and found the following link

http://www.lexus-tech.eu/legacy/Lex....asp?mscssid=aimUser1211229&d=1&admin=&lan=De Scroll Down and you will see Bicycle holder vehicle bracket (Easy Click)
Part Number :
PZ408-Z0690-00

If you click on the magnifying glass to the right it will open the installation instructions. On Page 26 you see that you remove the tow hooks to mount the Vehicle Bracket.

Now if you head over to the Curt Site

CURT Manufacturing | CURT Manufacturing - CURT Trailer Hitch #112000
In the instruction manual, it mounts to the same points that the Lexus Bicycle Holder Vehicle Bracket Mounts to.

Back to the first lexus-tech link Scroll Down and Find Bicycle Holder (Easy Click) LHD & RHD 13 PIN
Part Number:
PZ408-0069*-00

Click the magnifying glass next to the installation manual and on page 2 it give the max weight of the bikes as well as the weight of the rack itself. The rack weighs in at 16.5kg or 36.38 lbs, you can then add a max load of 36kg = 79.37lbs for a total weight of 115.75lbs

I am going to be using a Kuat Sherpa @ 29lbs + 2 road bikes at ~18lbs each => 65lbs well below the rack that lexus supplies.
This is enough information to put my mind at ease. And hopefully it helps some others make a decision.
 

·
Registered
Joined
·
441 Posts
I think it's hard for Lexus to make exceptions. People may install a hitch for one reason and then it so easily gets used for another. Maybe the car gets sold with the hitch on to a guy with a 55 foot caravan. You would think a hitch for bicycles could be ok together with some common-sense, but where do you find common-sense these days? No wonder Lexus just say 'no'.
 

·
Registered
Joined
·
169 Posts
You would think a hitch for bicycles could be ok together with some common-sense, but where do you find common-sense these days? No wonder Lexus just say 'no'.
Following that reasoning, Lexus apparently believes that common sense can be found in the EU, since the hitch for bicycles is available from Lexus there...
 

·
Registered
Joined
·
15 Posts
Hi all,

Thanks for the tips and hints on installing this hitch. I got the hitch installed yesterday without any major problems. I plan on hooking up a bike carrier (Thule T2 XTR). The installation instructions says a stabilizing strap is required for non-towing loads. My questions are: 1) Do I really need to use a stabilizing strap? 2) Where would I attach the strap to on CT?

Thank in advance,

Brian.
 

·
Registered
Joined
·
37 Posts
They mean you need a strap that holds the bike (for example) onto the rack -- just putting a bike on the rack unstrapped won't secure it. Totally common sense. :)
 

·
Registered
Joined
·
37 Posts
I just got my Curt hitch in the mail. I've only had my CT for a week! :)

Is it possible to install this hitch without ramps/jacks?

Also, I'm always worried about these notorious "clips" on cars and how once you yank 'em out, they never get put back on properly. Is there a big risk of that happening with the rear cover?
 
Joined
·
232 Posts
There is no such thing as "void your warranty". Lexus can refuse to repair issues caused by installing a hitch (assuming the manual says not to), but they cannot void your whole warranty.
I beg to be different.

If you mess around and cause structural damage to the frame of the vehicle as whole, the manufacturer will void the warranty. Similarly if you exceed the capability of what the engine can deliver you will also risk the liability of losing warranty. CT200h structural design is basically a monocoque unity body. There is no chassis, it is in essence just an egg shell. Land Rover Defenders in contrast got a pair beefy chassis made of C-channels that runs the entire length of the vehicle from bumper to bumper. You can attach a Class IV hitch to these C-channels.

I will compare to Subaru Outback's body which is similar to CT200h, but Subaru designed reinforcements a key points where a Class I hitch can be safely attached for its rated towing of 2K Lbs and tongue weight of 200 Lbs. Besides Outback also got a separate cooler for its CVT which is similar to CT200h's CVT; in other words Outback's continuous variable transmission fluid is cooled by a inter-cooler, and it also got a cartridge filter designed specifically for severe duty, i.e. towing applications.

CT200h's propulsion system is stretched to its maximum. The little 2ZR-HSE, a 1.8L 4 cylinder Atkinson is a low compression high rpm engine, developing maximum 105 Ft-Lb @ 4,000 rpm, which IMO is not conducive for towing. As pointed by others in US Owner's manual towing is not recommended for this very reason. There isn't just any "whoomp" left other than to carry the rated gross weight of the CT200h.

Lastly, for those of you who wish to carry a bike on a Class I hitch mounted on a CT200h, cautious must be observed to the tongue weight of 200 Lbs. To be safe, just follow the original car manufacturer's recommendations not the aftermarketer.
 

·
Registered
Joined
·
37 Posts
Why, then, does Lexus offer a trailer hitch for bikes from the factory? I called the dealer today and asked if it's possible to get the Euro-market hitch installed by them, they said they'd gladly do it.

If the car is already stretched to its maximum, how could it possibly stand to be as reliable as anyone would reasonably expect?

If I'm driving by myself with a 15lb bike on the back, how is that causing more strain on the engine and transmission than me plus five 140lb passengers?
 

·
Registered
Joined
·
5 Posts
Hi all,

Thanks for the tips and hints on installing this hitch. I got the hitch installed yesterday without any major problems. I plan on hooking up a bike carrier (Thule T2 XTR). The installation instructions says a stabilizing strap is required for non-towing loads. My questions are: 1) Do I really need to use a stabilizing strap? 2) Where would I attach the strap to on CT?

Thank in advance,

Brian.


I recently installed the curt hitch as well. Very easy install.

I bought the strap but it seems to put a lot of tension on the spoiler. I think I will be using it unless someone else on here can confirm it won't damage the spoiler.
 

·
Registered
Joined
·
5 Posts
Thanks for all the great info on this thread! I will be purchasing a ct and ordering my hitch the day I drive it home. Mtn bikes is my passion, so I will have a bike or two on the back 3-4 days per week. Question is, how has it worked out for those that have used it? Does it sag the back with 2 bikes, and how has it effected your gas mileage? I know the drag from the wind will effect the mileage. Any real world numbers with bikes on and just rack on?
Thanks in advance,
 
61 - 79 of 79 Posts
Top