Author Topic: Electric brakes  (Read 3156 times)

Mr. Breeze

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Electric brakes
« on: August 18, 2017, 12:06:32 PM »
We plan on ordering a 8.0 or possibly a 10.0 in the spring. I will be towing with a 2013 RAV4. Should I get the trailer brakes?

DavidM

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Re: Electric brakes
« Reply #1 on: August 18, 2017, 12:34:26 PM »
I would never dissuade someone from getting trailer brakes. But my personal rule of thumb is that if your trailer weighs less than half of your TV then you will be ok with no brakes. Since the Rav4 has a curb weight of about 3,600 lbs and the GVWR of the 8 or 10 is about 1,700 lbs, then the trailer will be less than half of the trailer's weight, particularly with driver, passengers and fuel.

How did I come up with this rule of thumb? Well a TV by itself will stop at a rate of about 0.8 g, g being the acceleration (or deceleration in this case) due to gravity. If you combine the weight of the TV with a trailer that is half its weight, the deceleration will be about about .53 g. That to me is acceptable, given that while towing you will maintain a longer distance behind the guy in front of you and generally drive conservatively.

But if the trailer weight is equal to the TV's weight, then the deceleration drops to .4 g. That is unacceptable to me.

In your specific case, your TV probably weighs 4,000 lbs or more. So your trailer weighs about 43% and your maximum stopping deceleration will be about .56 g.

All of the above is based on some high school physics and what I have read about stopping rates in road test magazines.

David

smjcolsga

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Re: Electric brakes
« Reply #2 on: August 18, 2017, 12:50:20 PM »
Is your Rav4 already set up to use trailer brakes?  (i.e. 7-wire connector, under-dash connections for the brake controller, etc) if so, then its a no-brainer, get the brakes. If not, then you may want to weigh the expense of adding or converting from a 4-wire to the 7-wire setup against the additional wear and tear on your Rav4's brakes and transmission having to deal with the extra half to 3/4 ton of mass all on its own. I have a QS 10.0 with brakes which I tow with a Volvo V50 sportwagon set up with a Hayes G2 brake boss proportional brake controller and barely feel the trailer is back there, even when on hills and for 'quick stops'.

Also, look in your Rav4's owners manual, many of them specify maximum safe towing limits with and without trailer brakes.
« Last Edit: August 18, 2017, 01:28:21 PM by smjcolsga »

PYG RYDR

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Re: Electric brakes
« Reply #3 on: August 18, 2017, 03:37:38 PM »
A quick Google search-

2013 Toyota RAV4
Compact sport utility vehicle
MPG: Up to 24 city / 31 highway
Towing capacity: 1,500 lbs
Dimensions: 180″ L x 73″ W x 65-67″ H
Horsepower: 176 hp
Cargo volume: 38.4 ft³, 73.4 ft³ with seat area

The RAV4 may be over maxed with the camper you want.

Mr. Breeze

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Re: Electric brakes
« Reply #4 on: August 18, 2017, 09:53:14 PM »
Thanks everyone! The owners manual says 1000lb with out brakes 1500 with . 10.0 weighs 1100 as far as I can tell. Tongue weight is 135 . Max tongue weight on rav is 150. So I think I'd be ok towing with the RAV4 ( depending on how much options weigh ( as long as I get the e-brakes)

smjcolsga

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Re: Electric brakes
« Reply #5 on: August 18, 2017, 10:31:42 PM »
As an additional point to consider, you should be aware that the published specs you referenced are only estimates (based on who knows what) and 'real' weights can vary considerably. For instance, my 2018 10.0, with options, has a measured weight of over 1280 lbs and a tongue weight measured at 190 lbs as was noted on the sticker each unit will have affixed from the factory.
« Last Edit: August 19, 2017, 06:30:14 AM by smjcolsga »

grecamp

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Re: Electric brakes
« Reply #6 on: August 20, 2017, 04:27:42 PM »
I tow my 8.0 with the super awesome V6 Rav4 and this is a much better TV with the extra 100hps. It is a huge loss to the civilization that Toyota abandoned the V6 in RAV.

Re  brakes - you can do without them but once you add them on you will be glad you did. Properly adjusted e-brakes will make the braking process much more comfortable, especially on a slope.

One word of advice: most likely you will be adding the breakaway kit as well. If your camper has a battery make your life much easier by connecting the kit to the camper battery vs adding one more, small battery from the kit as well. Perhaps you can even buy a kit with no battery at all and save a few $$$.

The installation is fairly simple but I recommend that you find some kind of 3-way wire connector as there are many cases where you will have to connect 2-1 (Y) wires and butt connectors are not that great for that.

Mr. Breeze

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Re: Electric brakes
« Reply #7 on: August 20, 2017, 08:48:59 PM »
Are they automatic or do I control the trailers brakes?    I guess I'll find out what a breakaway is ,
and if I need one.       
              Thanks, Sig

smjcolsga

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Re: Electric brakes
« Reply #8 on: August 20, 2017, 09:06:09 PM »
Are they automatic or do I control the trailers brakes?    I guess I'll find out what a breakaway is ,
and if I need one.       
              Thanks, Sig


Yes and No. You will need a brake controller to automatically actuate the trailer brakes whenever you press on your brake pedal. You can also manually apply just the trailer brakes alone using the controller (to calm a trailer which is beginning to sway, for instance) There are two basic types of controllers, time-delay and proportional, you should google these to understand the difference in how they operate. A break away switch will use a battery to acuate the trailer brakes in the event the trailer becomes separated (or breaks away) from your tow vehicle. This is to hopefully prevent a 'run-away' trailer from causing an accident if it should come off your hitch.

Capt J-rod

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Re: Electric brakes
« Reply #9 on: August 21, 2017, 01:49:10 PM »
Tekonsha makes a great controller. Your Toyota might be pre wired under the steering wheel. I also suggest looking at a scan gauge or ultra gauge to monitor your transmission temps. You may find yourself looking into a transmission cooler. If you didn't already know, you should never tow in overdrive. It will cause pretty serious damage to your transmission.

smjcolsga

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Re: Electric brakes
« Reply #10 on: August 22, 2017, 09:10:51 AM »
Some automatic transmissions now have a 'manual mode' option where you can override the automatic shift points programmed in the transmission. It is advisable to use this option while towing, it is not so much the overdrive gearing that is bad, as long as your engines revs are up high enough, but you definitely don't want to bog down the motor or have the tranny constantly 'hunting' a gear (ie shifting up and down from 5 to 4 to 5, etc).