For the record, I did not actually ride from Haleiwa all the way to the Dole Plantation and Maze. I chose to share the day with Pattie.
Pattie is an avowed flat-lander. She hates to ride up hills. But, lately she has been softening her stance, and I decided that this was an opportunity to prove to her that she really can climb hills. So we rode together, which meant cutting my ride short. I have zero regret, because it was so satisfying seeing her up on the hill. She took the pic below -- the one in the middle -- to show how high she got. For her this is a Really Big Deal.
The Tantalus climb has some pretty steep sections. I can do it well enough on my Merlin, but it is an extraordinarily light frame and I have a 28-tooth Dura-Ace cassette on a set of HED Ardennes wheels. It practically climbs all by itself. My still mostly stock P3 came with an Ultegra 11-25 cassette and those three extra teeth do make a difference. However, the Merlin has a 53/39 in front while the P3 is a 52/36. To get a real comparison we have to do a little math. Relax, it's not algebra.
Merlin lowest gear 39F / 28R = 1:1.393
P3 lowest gear 36F / 25R = 1:1.44
This tells us that the Merlin has a slightly higher gear ratio, meaning that its crank is spinning slightly faster that the P3's would going the same speed up the hill. Or, the Merlin would feel easier.
Going a step further, the next lowest gear on my Merlin is a 25, same as the P3, so
Merlin next lowest gear 39F / 25R = 1:1.56
In other words, the lowest gear on the P3 falls in between the lowest and next lowest gear on the Merlin. So, if both bikes weighed the same the Merlin should climb better. But they don't weigh the same. Not by a long shot. The P3 may be the latest and best carbon fiber tech, but my trusty Merlin Magia is much lighter. I could definitely feel the difference, the combination of a lower gear ratio and a heavier bike. The good news is, I was strong enough to do the ride.
Let's compare today's Tantalus climb with the last part of the climb to Hawi, roughly equal distances. Below are the map & graph displays from Training Peaks, with Hawi first. (click to enlarge)
Last 4.5 miles to Hawi
Climbing portion of Tantalus ride
The first thing to point out is that Training Peaks does some automatic axis scaling. Here, the vertical axis is not the same scale. Check the elevation gained numbers. For Hawi the gain was 490 ft, followed at the end by a drop of 121 ft as you enter the town. For the Tantalus climb the elevation gain is 1,383 ft. If you can make out the scale markings, along the right side closest to the axis, the Hawi chart is marked 164 - 656, a range of 492 ft., whereas the Tantalus chart goes from 328-1,640 for a range of 1,312 ft. The point here is that Tantalus overall is a much steeper climb than Hawi. Want more proof? The average grade for the Hawi segment is 1.5%, whereas for Tantalus it is 5.7%. Ka-Pow!
Just for kicks let's compare how hard I was working. First, my intent. For Hawi my focus was on experiencing the road, not going all out. I was trying to keep my heart rate in zone 2 as much as possible, but willing to let it rise when the grade because too steep. For today's ride my goal was to start in power zone 3 and hold that until my HR came up and matched, then allow both the get up into the low 4's from time to time. My average HR for the Hawi segment was 124 BPM, and for Tantalus, 129. My HRZ 2 is 111 to 125 BPM, and my HRZ 3 is 126 to 130. So I achieved my goal in both cases, and I ws working a lot harder today.
Now we can compare HR to power. For Hawi my NP was 110 watts, and for Tantalus, 139 watts. I don't know if it is legit to describe NP in terms as zones, but if it is, that would be PZ 2 and PZ 3. Even better proof I was working harder today, except pf course that the overall ride was much shorter.
To be clear, this Hawi segment is not the entire ride, just the last part, the long, steady climb. Before that there is about fifteen miles of ups and downs.
One more thing to look at is average speed. For Hawi, 6.47 m.p.h. For Tantalus, 4.96. Any slower and I would have fallen over, and that is in spite of working at a higher power output. A steeper grade does that.
I didn't get much data on the Pineapple Hill ride, but the portions of the road I did climb averaged around a 3% grade. Halfway between Hawi and Tantalus. I think it flattens out a bit further up the road than I went. From the base of the climb to the Dole installation runs about five miles, so a good Hawi simulation -- endurance-wise -- would be at least two repetitions.