2006 Outlander towing a 16'5" boat????

[ezmobee]

Re: 2006 Outlander towing a 16'5" boat????

My comment was not really in relation to THIS specific thread. It was more a general comment on all the "it's just down the road" excuses other people try to make on here. For this thread, if the towed load is within the towing capacity of the OP's vehicle, then by all means go for it.

As for the braking capability of a car vs. a truck I will agree with that. However, the braking doesn't do you any good if the trailer pushes the car sideways or some other "tail wagging the dog" scenario. A car towing at it's max capacity is going to have a greater chance of that occurring than a truck towing at half its capacity.

 

[109jb]

Re: 2006 Outlander towing a 16'5" boat????

What makes you think a 3300lb vehicle towing 1500 lbs with four 11.5 inch rotors (4800 lbs total per 289 inches^2 of rotor surface = 16.6 lbs per inch^2)

Is going to stop slower than a 5500 lb truck towing 1500 lbs with 4x12.5 inch rotors (7000 lbs total per 314 inches^2 of rotor surface= 22.3 lbs per inch^2)

Or stop slower than a 5500 lb truck towing 4000lbs with the same 4x12.5 inch rotors (9500 lbs total per 314 inches^2 of rotor surface = 30.3 lbs per inch^2)

Trucks empty have much longer stopping distances than cars, yet you never hear "what if someone pulls out in front of you on the way to the store?" Why does it only matter on the way to the dock?

And what magic makes these trucks with much longer stopping distances all the sudden perform so much better when towing a heavy load?

First of all, your calculations are totally wrong. It appears that you calculated the rotor areas above like this:
diameter * Pi * 8
with 8 being 4 rotor with 2 sides each

This is totally wrong. The area of a circle is
radius * radius * pi()
Even that would be wrong since the pad contact area isn't the whole circle.

Secondly, the area of the rotor is not the only thing you want to look at. Brakes are rated in the amount of kinetic energy that they can dissipate. Rotor contact area plays a role, but so does the size of the pads, the pressure applied to the pads, and the diameter of the rotor. The diameter difference alone in your examples puts the 11.5 inch rotor at a 9% disadvantage to the 12.5 inch rotor (think lever arm). Truck calipers also have larger cylinder diameters and operate at roughly the same brake line pressure so they squeeze the pads harder. They also have larger pads for more contact surface on the rotor. Now get into the difference in the mass of that truck rotor compared to a car rotor.

While it is true that a truck has a longer stopping distance than a car when NOT loaded, this will not be the case if both vehicles are loaded with any substantial amount of cargo

 

[fsds123]

Re: 2006 Outlander towing a 16'5" boat????

First of all, your calculations are totally wrong. It appears that you calculated the rotor areas above like this:
diameter * Pi * 8
with 8 being 4 rotor with 2 sides each

This is totally wrong. The area of a circle is
radius * radius * pi()
Even that would be wrong since the pad contact area isn't the whole circle.

Secondly, the area of the rotor is not the only thing you want to look at. Brakes are rated in the amount of kinetic energy that they can dissipate. Rotor contact area plays a role, but so does the size of the pads, the pressure applied to the pads, and the diameter of the rotor. The diameter difference alone in your examples puts the 11.5 inch rotor at a 9% disadvantage to the 12.5 inch rotor (think lever arm). Truck calipers also have larger cylinder diameters and operate at roughly the same brake line pressure so they squeeze the pads harder. They also have larger pads for more contact surface on the rotor. Now get into the difference in the mass of that truck rotor compared to a car rotor.

While it is true that a truck has a longer stopping distance than a car when NOT loaded, this will not be the case if both vehicles are loaded with any substantial amount of cargo

You are correct, I went with the wrong calculations.
Corrected it would be:

5.8 lbs/inch^2 for the car
7.1 lbs/inch^2 for the truck plus 1500lb trailer
9.7 lbs/inch^2 for the truck plus 4000lb trailer

We are still talking a 20-30% or more increase in lbs/inch^2

I know the whole rotor is not used. I'd have to have 2 sets to compare but there won't be much of a difference in the % used for braking surface.

And I don't agree with your statement:
"Truck calipers also have larger cylinder diameters and operate at roughly the same brake line pressure so they squeeze the pads harder. They also have larger pads for more contact surface on the rotor. Now get into the difference in the mass of that truck rotor compared to a car rotor."

Yes, truck rotors tend to be a little thicker, but only when comparing the larger sized rotors, and only by the % that the rotor is bigger. If you took a 13 inch car rotor and compared it to a 13 inch truck rotor they are basically the same size and weight. The pads and pistons are only going to be larger by the same amount as the rotor is larger.

 

[109jb]

Re: 2006 Outlander towing a 16'5" boat????

You are correct, I went with the wrong calculations.
Corrected it would be:

5.8 lbs/inch^2 for the car
7.1 lbs/inch^2 for the truck plus 1500lb trailer
9.7 lbs/inch^2 for the truck plus 4000lb trailer

We are still talking a 20-30% or more increase in lbs/inch^2

I know the whole rotor is not used. I'd have to have 2 sets to compare but there won't be much of a difference in the % used for braking surface.

And hence even the calculation above means absolutely nothing

And I don't agree with your statement:
"Truck calipers also have larger cylinder diameters and operate at roughly the same brake line pressure so they squeeze the pads harder. They also have larger pads for more contact surface on the rotor. Now get into the difference in the mass of that truck rotor compared to a car rotor."

Yes, truck rotors tend to be a little thicker, but only when comparing the larger sized rotors, and only by the % that the rotor is bigger. If you took a 13 inch car rotor and compared it to a 13 inch truck rotor they are basically the same size and weight. The pads and pistons are only going to be larger by the same amount as the rotor is larger.

And what happened to your original statement about an 11.5 inch car rotor compared to a 12.5 inch truck rotor?? Yes if you compare equal size rotors they are equal size, and if you compare equal size calipers they are equal size. If you think a typical car caliper or small SUV caliper is the same size as a full size truck caliper you are delusional. Believe what you want but the fact is that once you start adding trailer and payload the car stopping distance advantage is going away in a hurry.

 

[fsds123]

Re: 2006 Outlander towing a 16'5" boat????

And hence even the calculation above means absolutely nothing



And what happened to your original statement about an 11.5 inch car rotor compared to a 12.5 inch truck rotor?? Yes if you compare equal size rotors they are equal size, and if you compare equal size calipers they are equal size. If you think a typical car caliper or small SUV caliper is the same size as a full size truck caliper you are delusional. Believe what you want but the fact is that once you start adding trailer and payload the car stopping distance advantage is going away in a hurry.

Seriously? Did you think a larger rotor is not going to be heavier than a smaller rotor, by virtue that it is a LARGER rotor? I am talking percentages here. The 12.5 inch truck rotor is only about 10% larger than the 11.5 inch car rotor. It is also only about 10% heavier, and the caliper and piston are only 10% larger. Yet it has to stop a MORE THAN 30% heavier vehicle.

Do the math yourself. Increasing the brake components by 10% while increasing the weight of the vehicle by 30% is not going to stop you quicker. Why do you think the empty truck has a longer stopping distance in the first place?

In your opinion, at what point does the car stopping distance advantage go away? At what trailer weight? Show me the math.

 

[ezmobee]

Re: 2006 Outlander towing a 16'5" boat????

Keep it civil or this will be closed (I know I am just as guilty).

 

[reelnative]

Re: 2006 Outlander towing a 16'5" boat????

all you guys make me laugh and spit my soda out my nose, this guy wants to tow a rig that weighs less then my brothers wife and you telling him to go weigh it and be carful, well everyone needs to be carful when towing anything, but what this guy wants to tow somthing that just about could be towed with an mg miget

 

[made in china]

Re: 2006 Outlander towing a 16'5" boat????

First off, to the OP: Your car is NOT an SUV. That term is being used wayyyy too loosely. It is basically a 4 cyl. Galant with ground clearance.

I'd also like to add to the arguments about vehicle capacities, comparing trucks to cars. I tow 2500 pounds with a Maxima (short distances). Tows great. The car is overbuilt, trust me. I have confidence in the car. The brakes, engine, wheelbase are all up to the task. The tow hitch, type III up to the task. BUT let me bring into play ANOTHER weakness of cars (like your "SUV" car-crossover thingy) the TIRES. I need new tires for my Maxima. With cars you gotta be careful about your tires too. They really aren't designed with heavy towing in mind, and many cheaper models have very low weight ratings. Shopping for tires for my Maxima showed a rated disparity of almost 300 pounds between tire models that were competitive within a few dollars of each other.
And of course your insurance company will act like they never heard of you when/if you have an accident.

I am not saying you can or can not tow, but check your tires too. Cheap tires? Figure that into your considerations. There will be a load rating on the sidewall of the tires.

 

[109jb]

Re: 2006 Outlander towing a 16'5" boat????

Seriously? Did you think a larger rotor is not going to be heavier than a smaller rotor, by virtue that it is a LARGER rotor? I am talking percentages here. The 12.5 inch truck rotor is only about 10% larger than the 11.5 inch car rotor. It is also only about 10% heavier, and the caliper and piston are only 10% larger. Yet it has to stop a MORE THAN 30% heavier vehicle.

Do the math yourself. Increasing the brake components by 10% while increasing the weight of the vehicle by 30% is not going to stop you quicker. Why do you think the empty truck has a longer stopping distance in the first place?

In your opinion, at what point does the car stopping distance advantage go away? At what trailer weight? Show me the math.

I have no math, but would argue that your math shows absolutely nothing.

I just did about 2 minutes of internet research and found an article that says the following:

"3) Only increasing the effective radius of the disc, the caliper piston area, the line pressure, or the coefficient of friction can increase brake torque. Increasing the pad area will decrease pad wear and improve the fade characteristics of the pads but it will not increase the brake torque. "

Three of those items mentioned, disc radius, caliper piston area, and lines pressure, verify what I said in my previous post. The last, pad size makes sense and I will admit that it is only for pad wear. Notice that the article makes no mention of the area of the rotor.

I have no math, but have years of experience towing with everything from small cars, mini and full size vans, mini mid and full size trucks. From my personal experience I would take a full size truck over any of the others and that includes the braking ability.

In any case, this thread has diverted from what it should have, Seems like they always do. The only thing that matters for this post is whether the original poster's Outlander can tow his boat. In that regard I stand by what I said before. If the boat is within the manufacturer towing limit then he can do it. We have established that the manufacturer towing limit of the vehicle is 1500 pounds when properly equipped. If the actual boat weight is 1500 pounds or less he can tow it. If not, then the boat should not be towed with that vehicle. We don't know what placed the manufacturer limit at 1500 pounds. Could have been brakes, could have been drive train, could have been power, could have been something else. We don't know. What matters is that if you exceed the limit you could be sacrificing safety or the longevity of your vehicle and in my opinion the manufacturer limit IS the limit.

I'm done.

 

[JaseBosto]

Re: 2006 Outlander towing a 16'5" boat????

I agree with the previous, but doubt your boat will exceed it.

 

[JoLin]

Re: 2006 Outlander towing a 16'5" boat????

So, if I understand all this correctly, if I measure the brake rotors, calipers, swept area, master cylinder bore size and the area of my shoe when I drag my foot a la Fred Flintstone....

It should prove that my wife's Rav4 is just as capable at towing, as my Dodge?

That is WAY COOL!

 

[JaseBosto]

Re: 2006 Outlander towing a 16'5" boat????

It appears that is the case here