Just went up a 15% grade in SW Pa. last night with 4-6" of new snow on the ground. I kept it at 15 MPH and my wheels (FWD only) never broke loose once.

After parking all night, snow piled up to more like 10-12" ( deeper than the oil pan ) and my FEH pulled out of my parking space just a idle without even my foot on the gas.

Simply.... amazing....

 

A 15% grade is only 8.53 degrees which really isn't very much.

 

You haven't driven some of the 15% grades out here in our region. I84 east of Pendleton OR comes to mind.

 

I could be confused but are there different 15% grades?

 

Oh, very, VERY much so.

For roadbeds.

 

Please explain why 15% grade/slope or 8.53 degrees is somehow different depending on what? In distance, yes but it's still 15%. My driveway has a grade/slope but I don't see why the same grade/slope would be different in a different state!

 

Sorry, you'd have to drive it in the dead of winter to understand.

 

Nope! Just want to know why a 15% grade/slope is different in Oregon compared to other states?

 

My experience supports the difference in "15%" slopes.

While naturally a true 15% slope is always the same grade, but unfortunately the road signs are used very loosely. So, in one town 15% sign might be on a slope closer to 10%, in an other town it may be used for slope closer to 20%. Yes, it shouldn't be like it, but that's just life...

Also 15% for a car is quite a steep slope. And specially if it is slippery.

 

A 2% grade is "strong" for a mainline railroad. 3%, very steep, and 4% too steep for practical use.

5% to 7% is very steep for a 80,000# tractor/trailer.

15% for a regular automobile is indeed VERY steep.
I've had my FEH on a 24% dirt road, and while it wasn't, it felt like the front wheels were ready to come off the ground going uphill.

( 4,000 RPM at 10 mph by the way )