A few random, almost-off-topic observations on motor cut-out and calculating grade:
That pause or hesitation on steep uphills can really be dangerous as suddenly the forward momentum is gone. Wobble, wobble, crash!
I can only imagine, because so far, I have had little difficulty crashing trying to make it up Hell Hill even with a perfectly functioning motor!
What you describe would be far worse. When I have crashed due to traction loss and sliding backwards, I usually have several seconds of warning because I know I'm on a trick stretch of trail, and something bad will probably happen. That makes it much easier to jump off or lay the bike down somewhat gently. (And I am also on dirt.) If the motor cut out unexpectedly and completely on pavement, particularly at high boost, that seems potentially way more dangerous.
that said - a 20% hill is VERY steep. extremely unusual for a paved road, which are typically designed to max out from 6-10 percent in most of the relatively recently built western world. it takes almost 800 watts of power to propel a 260lb object (bike plus rider) up a 20% grade at 7mph.
Indeed, it is-- and 7mph sounds about right. Just for the hell of it, I took a route today that had a short segment of 15% on pavement and a much longer segment of 12-14.5% on pavement.
On a 46 pound bike with a 40 nm 250 Watt motor, bike + rider = 200 pounds, the motor did not seem to struggle at all. But it was very steep. Not like, I'm gonna die steep, but steep like I'm definitely stopping and hitting the water bottle (for the longer section, anyway.) Got home with compression long-sleeve undershirt, flannel shirt, and jacket lining drenched with sweat.
for a quick confirmation of a route, the rideWithGPS route planner shows a nice cross section of the terrain and you can see % slope along the ride.
Great tool, thanks so much for that! I will be using this a LOT.
However, I was confused at first, because this is giving me WAY lower grade readings than MTB project.
But I'm so glad you posted this, because it helped me finally figure out why different tools appear to give such different estimates of grade-- and this might explain why Jo could be seeing numbers close to 30% for this hill if he/she/they used an online tool to check. If the tool calculates based on 100 or 200 foot segments, you could get values that were twice as high. MTB project breaks trails down into teeny, tiny segments, so you can get some really high readings depending on where your cursor is placed on the map.
For example, Brand Park Motorway is the intermediate/advanced, and-- as a Senior Special Needs Extreme Athlete (
)-- the hairiest trail I've ever taken. RideWithGPS puts the max grade at about 14%-- but MTB project lists the max grade as 29% because it's looking at shorter segments-- 1/100th of a mile. So for about 52 feet, this particular trail does appear to be 29%. You can do a lot of crazy things for 50 feet that you couldn't do for 100, 200, or 500.
