When is a Steep Grade sign deceptive...?

[John E Davies]

I drive steep grades all the time, it is hard to escape them in this part of the country. When you see a percent listed on a sign it is the average “top to bottom” value. On Interstates and major highways that may be fairly accurate. On back roads, it is a fantasy.

There is a popular bicycle road going from the bottom of the Columbia Gorge near Lake Chelan, to the high rolling wheat fields up top. I have driven it several times in both directions. It is posted as 7.5%. In reality it has 15% stretches. It is a first gear, pedal to the floor experience going up with my Land Cruiser, and a first gear, sphincter tightening descent with way too many brake applications.

 

My GPS is set to show elevation and grade all the time. When it gets over 16% I start to get pretty darned concerned. Diesel trucks with engine brakes rule in this area.

For your entertainment, Harry Chapin 30,000 Pounds of Bananas .... https://m.youtube.com/watch?v=OGldNpngDws

John Davies

Spokane WA

Edited August 23, 2020 by John E Davies

[Popcorn-Billy]

John,

I'm my experience, curves exacerbate the gradient. I tend to over slow entering a curve and allow the vehicle to accelerate through it. My concern has been that the tail would wag the dog. I had that experience once while towing a too long trailer with my old "Boxtop" Cherokee. Another motorist entered the road when I was in the middle of a downhill curve. It got exciting and I promised myself I wouldn't drive a too small TV. That's why buying an Oliver will involve my trading in my 2013 4Runner for something more adequate. A used Land Cruiser is in the running. I just wish they had a tow-haul mode.

[Ray and Susan Huff]

59 minutes ago, Popcorn-Billy said:

John,

I'm my experience, curves exacerbate the gradient. I tend to over slow entering a curve and allow the vehicle to accelerate through it. My concern has been that the tail would wag the dog. I had that experience once while towing a too long trailer with my old "Boxtop" Cherokee. Another motorist entered the road when I was in the middle of a downhill curve. It got exciting and I promised myself I wouldn't drive a too small TV. That's why buying an Oliver will involve my trading in my 2013 4Runner for something more adequate. A used Land Cruiser is in the running. I just wish they had a tow-haul mode.

Tow-haul mode in our pickup is a great feature.

 

[Galway Girl]

I know many trucks now have displays that show pitch/yaw etc. but they are usually in degrees.
It' handy to have a table like the one below to know how the GRADE sign might look on your display in degrees.
So for John's example above the 15% grade would show up as about 8.5 Degrees in angle on the dash display.
And 8.5 doesn't sound bad, but it feels horrible if you're being pushed down hill by a trailer that's heavier than your Tow Vehicle.

[BackofBeyond]

I don't worry or think about the up or the down. I tow with a 3/4 ton duramax powered truck. Going up, its no issue, ( tow haul mode or not) going down, hit the engine brake switch, and go back to listening to my spouse .......

Must admit - somewhere out west, there was a above normal - maybe 12%  grade - I mentioned it to the copilot, she replied, hmmm. ok. 

Have fun

 

[Ray and Susan Huff]

On 8/28/2020 at 2:02 PM, ctshort09 said:

I know many trucks now have displays that show pitch/yaw etc. but they are usually in degrees.
It' handy to have a table like the one below to know how the GRADE sign might look on your display in degrees.
So for John's example above the 15% grade would show up as about 8.5 Degrees in angle on the dash display.
And 8.5 doesn't sound bad, but it feels horrible if you're being pushed down hill by a trailer that's heavier than your Tow Vehicle.

Not that it matters, but our BMW X-drive will display the pitch and yaw.  What I didn't know is that the angle and %grade are not the same.  Our private road has a short climb that displays as 18 deg on the BMW display.  So is it actually 32.5?  I'm going to have to check it out and see if the display says degrees.  No wonder I struggle to pedal my bike up that hill!