# Using the parking brake when towing? **URL:** \ **Category:** Factual Questions\ **Created:** [November 14, 2015, 12:47am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510 "2015-11-14T00:47:42Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [November 15, 2015, 11:49pm UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/21 "2015-11-15T23:49:31Z")
> [@bob\_2](#): > > On vehicles with drum brakes on the rear wheels, applying the park brake operates the adjustment to allow for wear on the pads. If you _never_ use it, the brakes will lose efficiency over time. Drum brakes have shoes [discussed below], not pads. On some rear disc brake designs what you stated is true, it’s necessary to actuate the parking brake for the calipers to adjust to pad wear. > [@Rogon](#): > > Brake adjusters on drum brake cars adjust when brakes are applied in reverse, not when the parking brake is used. This is true of most vehicles with self-adjusting brakes. That was true of American cars decades ago. In more recent times, there are various self-adjusting designs, and on many cars the brakes will adjust when the parking brake is applied or when the service (regular foot) brake is applied, regardless of whether the wheel is turning. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 16, 2015, 12:03am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/22 "2015-11-16T00:03:20Z")
> [@barbitu8](#): > > Once you reach 5 mph or so, you get a warning sound - at least on my Honda. That’s actually pretty cool. I’ve never been in a car with that feature–would be useful. ---
**Author:** ![drad\_dog](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@drad\_dog](https://boards.straightdope.com/u/drad_dog)\ **Post date:** [November 16, 2015, 1:57am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/23 "2015-11-16T01:57:42Z")
> [@Earl\_Snake-Hips\_Tucker](#): > > But while you’re parked, of course. 😃 > > Anyway. . . I have a \*friend who insists on engaging the parking brake when parking a tow. So far as I know he doesn’t engage it in most other circumstances, other than in an ususual sort of case like parking on an incline. > > While I can’t see that engaging the parking brake doesn’t do anything harmful, I’ve always wondered is it really doing any benefit? His only comment on it was his father had always done it, so he does it, too. So. . . Does it really gain you anything in most cases? > > \*Yes I do. Seriously. So nobody feels like explaining what “parking a tow” is? ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [November 16, 2015, 2:19am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/24 "2015-11-16T02:19:52Z")
> [@kanicbird](#): > > What is parking a tow? which vehicle is he applying the e-brake to? The powered one pulling or the one being towed? > [@drad\_dog](#): > > So nobody feels like explaining what “parking a tow” is? I understand it to mean parking a vehicle that is being used to tow a trailer, with the trailer still attached. The discussion is about applying the parking brake of the towing vehicle. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [November 16, 2015, 2:23am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/25 "2015-11-16T02:23:01Z")
> [@drad\_dog](#): > > So nobody feels like explaining what “parking a tow” is? Eh. . . Problems accessing a dictionary, eh? > [@Merriam-Webster](#): > > [Tow:](http://www.merriam-webster.com/dictionary/tow) > **3a: something towed (as a boat or car)** Hope that helps. 😃 And. . . although I wasn’t clear, I was referring to parking a vehicle with auto tranmission. Thanks, all, for the responses. ---
**Author:** ![drad\_dog](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@drad\_dog](https://boards.straightdope.com/u/drad_dog)\ **Post date:** [November 16, 2015, 2:49am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/26 "2015-11-16T02:49:23Z")
> [@Earl\_Snake-Hips\_Tucker](#): > > Eh. . . Problems accessing a dictionary, eh? > > Hope that helps. 😃 > > And. . . although I wasn’t clear, I was referring to parking a vehicle with auto tranmission. > > Thanks, all, for the responses. You seem to be in disagreement with Gary T. I got no skin in the game but does a dictionary really do it here? ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [November 16, 2015, 4:09am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/27 "2015-11-16T04:09:48Z")
> [@drad\_dog](#): > > You seem to be in disagreement with Gary T. I got no skin in the game but does a dictionary really do it here? I don’t think it’s a disagreement but rather a difference in how to say it. Context in the OP seems pretty clear to me: the question is about using the parking brake in a car when it’s towing something, in contrast to usually not setting the brake otherwise (with the occasional exception of something like parking on a hill). And again context tells me that “parking a tow” doesn’t mean simply parking whatever is being towed – the literal dictionary meaning – but rather parking the combination of tow vehicle and trailer. Presumably the OP figured that last bit would be understood, which is not unreasonable but in my opinion can easily be misconstrued. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [November 16, 2015, 5:41am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/28 "2015-11-16T05:41:13Z")
There are certain conditions of water/wet muddy water on a runway and temperatures where the habit of touching to brakes to spot wheel spin can leave you with a wheel frozen to a break pad. There is usually a rub bar to stop wheel spin just before it goes into the stowed position on retractable gear aircraft. That way the pads are not touching when the wheel is stowed. No frozen wheel. No I don’t think a 747 would have a problem breaking loose the wheels if they were frozen to the pads when they land but it could cause some expensive/dangerous damage to the plane. Even on a small training aircraft with fixed gear, I always advocated not stopping wheel spin with the brakes unless actual thought and planing and knowing all the conditions made it a good idea. Landing a conventionally geared plane with locked wheels can be extremely exciting quickly. Actually, I was taught to move my feet on final to such a position I am only working the rudder and that no bounce nor accident could make me hit the brakes unintentionally. Same applies to cars that go through water, like breaking through a puddle covered with ice as you are parking and then applying the parking/emergency brake. Very easy in 30° weather to come back to a frozen wheel. 1 easy in \< 30° weather 2 easy in \> 30° weather 3 easy in 30°\< weather 4 easy in 30°\< weather Which is the correct way to say/indicate “easy in 30° or less temperatures for ice to lock the breaks.” I never have learned a good rule for this… easy in 30° weather ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [November 16, 2015, 5:50am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/29 "2015-11-16T05:50:53Z")
I had to read a couple of answers here before I figured out what “parking a tow” meant. I first thought it was about parking a towed vehicle. I spent a lot of time driving 18 wheelers with automatic transmissions. Well, for the tractor part, of course. There’s no P on the selector, so you just pull the yellow diamond shaped button to apply the parking brake to the tractor and trailer after you’ve set the transmission to N. But sometimes, instead of using the parking brakes, you’d just pull the red 8 sided trailer air button which cuts the air to the trailer, deflating your air suspension and applying the parking brakes too. You’d do that when you’re dropping a trailer. ---
**Author:** ![Jesta](https://avatars.discourse-cdn.com/v4/letter/j/c5a1d2/32.png) [@Jesta](https://boards.straightdope.com/u/Jesta)\ **Post date:** [November 16, 2015, 7:46am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/30 "2015-11-16T07:46:39Z")
How about the effect of the handbrake being off if the parked vehicle happens to be hit by a moving one? Is it more likely to keep rolling towards the playground, and also the moving car, that is still moving now too, would the handbrake have made any difference? At the traffic lights, couldn’t it stop you from hitting the car infront of you if you were tapped from the rear? As it is, I always apply the handbrake, auto or manual, just the way I was taught and I assumed everyone does! ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [November 16, 2015, 10:53am UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/31 "2015-11-16T10:53:00Z")
> [@Ranger\_Jeff](#): > > I had to read a couple of answers here before I figured out what “parking a tow” meant. I first thought it was about parking a towed vehicle. > > I spent a lot of time driving 18 wheelers with automatic transmissions. Well, for the tractor part, of course. There’s no P on the selector, so you just pull the yellow diamond shaped button to apply the parking brake to the tractor and trailer after you’ve set the transmission to N. But sometimes, instead of using the parking brakes, you’d just pull the red 8 sided trailer air button which cuts the air to the trailer, deflating your air suspension and applying the parking brakes too. You’d do that when you’re dropping a trailer. On a European truck, which are almost always auto’s these days, The drive selector is usually a dial on the raised part between the seats (where the gear lever used to be). The parking/emergency brake is usually a small lever behind it (or somewhere adjacent). In reality the lever is just a switch that applies the brakes to the drive wheels of the tractor unit and all the wheels on the trailer. Sometimes, there is a way of just applying the brakes to the trailer wheels so that the driver can test (by tugging) the coupling on a down slope. Dumping air from the trailer suspension is done with a button on the trailer itself. If you open the door of a truck, or my (automatic) car, without setting the brake, it sets of an alarm “Beep Beep BEEP!!!” ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [November 16, 2015, 5:24pm UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/32 "2015-11-16T17:24:19Z")
> [@kayaker](#): > > In my youth I was led to believe that in extreme cold weather, the parking brake could “freeze”. Extreme cold was fine. Slushy sloppy during the day, then freezing at night was what usually did it. Fords were (are? my newest car is a '97) very prone to this, not sure about other brands. I’ve never driven automatics, so setting the parking brake is “automatic” when I park a car. Really have to struggle not to when the weather makes it not a good idea. ---
**Author:** ![drad\_dog](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@drad\_dog](https://boards.straightdope.com/u/drad_dog)\ **Post date:** [November 16, 2015, 5:46pm UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/33 "2015-11-16T17:46:40Z")
Why is brake usage hooked to whether you are towing something? ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [November 16, 2015, 6:03pm UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/34 "2015-11-16T18:03:11Z")
> [@drad\_dog](#): > > Why is brake usage hooked to whether you are towing something? Additional weight that could drag both vehicles away. I always use it because it will rust and become totally inoperable after x number of years if I don’t. I know this from cars my dad owned when I started driving. ETA: I wasn’t familiar with the term “parking a tow” either. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [November 16, 2015, 6:21pm UTC](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510/35 "2015-11-16T18:21:13Z")
> [@Leaffan](#): > > . . ETA: I wasn’t familiar with the term “parking a tow” either. Well, since this seems to be a \*chock in the wheel of progress, some clarification: “Parking a vehicle with auto transmission which is still engaged with its towed load.” At least I didn’t turn head on a live game. \*But obviously chocks can be useful when parking a tow. 😃 [Previous page](https://boards.straightdope.com/t/using-the-parking-brake-when-towing/737510.md?page=1)