Hill descent assist

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jhild

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May 31, 2018
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Hi everyone. I have a 2013 VW Touareg TDI Lux and am pulling a 22' TT. This vehicle is equipped with a hill descent assist which is activated by switching to "off road". This only works if you do NOT touch the brakes on a descent. Question, will the hill descent assist activate the trailer brakes along with the vehicle brakes? Thanks
 

steveblonde

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no - sorry its designed for steep hills off road as you stated i also think that there is some sort of speed limiter on it maybe as low as 2-3 mph
 

Lou Schneider

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The best way to descend a grade is to manually select a lower gear so the engine can speed up and supply engine braking to hold down your speed.  A long time trucker's rule is to use the same gear or one lower going down a hill than you would use to climb it.

Then use minimal amounts of braking in short bursts if needed to further hold back the speed.

If your trailer has electric brakes and an external trailer brake controller like the Prodigy, it will apply the trailer brakes every time you apply the vehicle brakes.

If your trailer has surge brakes, where the force of the trailer pushing against the hitch provides the braking action, it will apply the trailer brakes lightly when engine braking is slowing the vehicle, then more heavily when you step on the brake pedal.
 

coxid

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The OP stated that he has a VW TDi. Diesels have LITTLE to NO compression braking unless it has an exhaust brake.
 

MtnGoat

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Our 2015 2500HD has grade assist that also has the control speed set too low. I have found using the exhaust brake with 2nd or 3rd set in manual, will maintain a decent speed without using the brakes.
 

Rob&Deryl

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coxid said:
The OP stated that he has a VW TDi. Diesels have LITTLE to NO compression braking unless it has an exhaust brake.

Huh?

Diesels have much higher compression ratios than gasoline engines. Foot off the fuel pedal provides pretty good braking if in an appropriate gear. Of course, engine exhaust braking adds substantially.
 

Gary RV_Wizard

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Lots of diesel compression on the power stroke, but it's a fee breathing engine so none at all on the other 3 strokes.  And no throttle plate on the air intake either. Net is zero back pressure.
 

Lou Schneider

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Right.  Compression acts like a spring - the energy used to compress the air in the cylinder is returned on the piston's downstroke.

It's external restrictions in the air path - the throttle plate on a gas engine's intake or an exhaust brake throttle plate on a diesel's exhaust - that provides braking force as the engine works to force air past them.
 

FlyboyT77

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Jan 15, 2020
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How does the Touareg TDI do towing a large travel trailer?  What's the weight of your TT?

I'm considering towing my TT with a dry weight of 4700 with it.  The trailer's GVWR is still under the max tow rating of the Touareg.  I do plan on buying a ProPride 3P to eliminate sway on the shorter wheelbase.  I currently tow with a 1500HD with the 6.0 gas (10k max towing).  The potential diesel mpg is very tantalizing and has more torque than the 6.0.
 

grashley

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Welcome to the Forum!

You may get more responses making this a new post.

Without more data, I would be hesitant to say it is good.  Towing ratings are based on towing a load of bricks on a flatbed trailer (no air resistance) and only 2 150 lb passengers and no other cargo or passengers.  Added weight reduces tow capacity.  It assumes a base level trim - no options.  Option weight reduces tow capacity.

What is the Payload for the Touareg?  Find the yellow border placard on the driver door latch pillar.  This must be able to carry the weight of all passengers, car seats, treats and cargo carried in the car PLUS 10 - 12% of the TT  GVWR plus the weight of the hitch.
 

Gary RV_Wizard

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From what I read, the Toureg TDI has a tow rating of 7700 lbs. That's sounds marginal to me if the dry trailer weight is 4700.  Remember that the tow rating does not include any gear load in the tow vehicle - it's just driver and passenger at 154 lb each. And the Toureg also has to carry 10%-12% of the gross trailer weight as hitch (tongue) weight.  That too is probably within the Touregs load limit, but up near the top end of it.  On general principle I'm leery of any car or SUV handling when its weight limits are being pushed.

Reports are that the Toureg is an excellent tow vehicle when compared to other SUvs, but that's not the same as your 1500HD.  If it's the diesel you want, there are half-ton diesel pickups available now. F150, Colorado, Silverado/Sierra, Ram,
 

ez3putt

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Payload for my 2015 Touareg TDI is 1180 lbs.  I have been pretty impressed with its towing capability and it's incredible torque.  I haven't tried to tow a 6000 lb. travel trailer, but I would not be afraid to.
 

steveblonde

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ez3putt said:
Payload for my 2015 Touareg TDI is 1180 lbs.  I have been pretty impressed with its towing capability and it's incredible torque.  I haven't tried to tow a 6000 lb. travel trailer, but I would not be afraid to.
a 6000 lb trailer will have 900lbs tongue weight which leaves you with less than 300lbs for people and junk and you would be bottoming out on every bump or crack in the pavement - not a good idea
 

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