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Thoughts on use transmission retarder with slippery road surfaces

November 02, 2022, 07:46:12 pm

Thoughts on use transmission retarder with slippery road surfaces

Some disagree, but most agree that when roadways are not dry, we need more deliberate braking and acceleration control.  Using retarders and cruise control tend to pass control to those systems with sometimes sudden actions.  Also, retarders slow coach by slowing rear axle without any slowing action of front axle.  Foot brake slows both axles.

Be very aware that on most Foretravel coaches with transmission retarders, pressing foot brake pedal (treadle) automatically actuates transmission retarder in one of three levels depending how hard the brake pedal is pressed.  This in addition to actuating normal coach air brake systems.  This happens even with retarder joy-stick in off (0) position.  Turning off side-dash panel retarder on-off electric master switch will prevent all retarder actions including with brake pedal. 

So, it is important to turn off retarder switch when retarder is not wanted.  While coach is being stored, some will take it periodically for an hour drive to warm up systems and remove brake pad glaze.  Turning off retarder electric switch is recommended during anytime we want to warm up brake pads. 

To exercise brake pads, especially after sitting for a while, it may be a good idea to drive in reverse with several strong brake pedal actions.  Retarder probably will not actuate in reverse.

On the other hand, keeping retarder joystick on in a non-zero position, may be helpful as whenever foot is removed from throttle pedal, retarder will actuate to slow coach, good idea in city traffic.

Searches on internet and our Forum will yield many ideas on the topic.

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Re: Thoughts on use transmission retarder with slippery road surfaces

Reply #1 – November 02, 2022, 08:00:16 pm

Using the retarder we stopped to fuel up, generally I shift the lever as far forward as it will go as soon as I have finished slowing and into the fuel stop we went,
Quick rain shower and we  were driving at about 30 mph around the curve of  the on ramp which also had to accommodate vehicles exiting the interstate and our coach entering the traffic flow , taking my foot off the accelerator, the retarder (which I had forgotten to turn off) cut in on max and the back of the coach was suddenly heading out sideways on to the interstate with the toad attached!
Quickly accelerating turned off the retarder and all was well,
Lesson learnt: don't leave it on :
Myth Busted: DONT USE ON A WET SURFACE, unless you want to test the power of your deodorant!

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Re: Thoughts on use transmission retarder with slippery road surfaces

Reply #2 – November 02, 2022, 10:15:31 pm

I use both my retarder and Jake brake in all kinds of conditions including snow. I manually use
both so I'm in control of the operation. The retarder joystick is always in the off position and the
Jake is controlled by a floor switch. In fact stepping on the Jake won't have my transmission shifting
down. I have a second switch floor switch for that. In Montana bringing the coach home in the snow
I hadn't pushed  the retarder joystick to the off position and took my foot of the throttle and it locked up.
I reacted and hit the throttle and every thing was fine. I try to stay off the brakes in the snow as it is hard
to steer with the brakes on.

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Re: Thoughts on use transmission retarder with slippery road surfaces

Reply #3 – November 02, 2022, 11:51:21 pm

For many years, bus companies operated without a Jake and with drum brakes, and did just fine. My old ex-Greyhound also had just the service brakes and went down lots of grades without any problems in the most difficult of conditions.

The service brakes are the primary means of stopping the coach. Retarders and Jakes are nice to have but are secondary and may extend the coach's operating envelope  but only with proper primary training.

I remember watching a King Air on final for a less than 4000 foot runway. Too high and too fast he landed more than half way down the runway and seemed sure to overrun the end of the runway. But lots of throttle with the props in beta mode stopped him just before the end of the runway. Saved his bacon and reputation...this time.

Pierce

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Re: Thoughts on use transmission retarder with slippery road surfaces

Reply #4 – November 03, 2022, 12:55:37 am

I've had the rear wheels rotate backwards running the electrical retarder in a tandem dump truck, ice covered road. Had to take a second look in the mirror cos I wasn't sure what I'd seen.

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