I tried a new candidate for toughest climb on asphalt in the state of New Jersey:
Breakneck -- way up north near Vernon [ see map ]
Thanks to David G for suggesting it to me.
Felt at least as tough as the notorious Fiddlers Elbow climb (way out west between Belvidere + Washington - see map). But that was on a hot day in full sun, and my first time trying it, so might not feel quite so hard a second or third time on a cooler cloudier day. (Fiddlers also feels pretty overwhelming to most people their first time). Somebody who's done both several times could give a better opinion.
Also very helpful is if somebody has some accurate elevation : distance measurements for Breakneck they could post here or send my by Private Message. By "accurate" I'm thinking like using a (expensive) GPS with a barometric altimeter, or a non-GPS bicycle cyclometer with altimeter (not from topo software, and not from a GPS lacking a barometric altimeter, because GPS units generally do not measure altitude really accurately).I like Fiddlers Elbow better than Breakneck, because I did not like the sharp curve in the midst of the steepest section on Breakneck Rd, and seemed like lots more car traffic than Fiddlers -- so more car drivers that might not see me as they come around that corner.The climbing felt so hard right then, I was thinking about what if I fell off my bike there and a car came around the corner while I was lying on the pavement still trying to get up.Also I like it that Fiddlers has much more shade. But one way they're the same is that their asphalt has coarser stones than most New Jersey roads, so the climbing requires more effort than you'd estimate from knowing the steepness grade. For now I've put them on the steep climbs of NJ list in a tie for 1st.
details: I got the maximum amount of climbing by starting below Breakneck Rd, first on Vernon Crossing (rt 644), then rt 515, which joins rt 94 for a short ways, then continue on rt 515 south (becomes Stockholm Rd), then in the midst of a steep-ish climbing section, I made a left turn (across traffic) onto Breakneck Rd going east -- which starts moderate, feels like a relief from rt 515. Then it gets real steep, then a little less steep, then really really steep. Warning sign at the top says 25% grade. (though I kinda doubt it's 25% for more than a short section) -- I'd easily believe there's a sustained section at least 20% grade, and lower down a section at least 16% grade.
Feeling lucky to have made it to the top, I didn't want to go back down a road that steep, so instead I rode south along the Wawayanda ridge on rt 638, then turned right onto rt 515 north back down to Vernon (rt 515 had a warning sign for 17% grade) -- to me it felt like the sustained steepness on 515 was more like 13%, which was plenty thrilling enough to go down.
There are some other interesting climbs around Vernon, connected by some pleasant, pretty roads [see report], I did about five of them as warmups for Breakneck, one afterward (which hurt).