Marathon or Century. Different but equally hard?

I am a much stronger runner than cyclist and I still think a century is way easier than a marathon.  But that being said when comparing different sports you will never get any accurate comparisons.  

Time wise a Metric century is closer to a marathon, but effort wise maybe a Metric double century?

100 miles on a bike....piece of cake

26.2 miles running.... slice of hell.

To make them more even, specify a finishing time.

4-hour century vs 4-hour marathon.  Now it's not so easy to say!!

Or to make it more fair, a sub 2:25 marathon vs. a sub 4 century.

DP

FTW

I have done 2 century rides, while I was stiff and sore a bit after doing them....the discomfort from those is NOTHING compared to how much I am disliking marathon training and I came into this a runner!

This.  You can BS a century.  You will have a much rougher time BS'ing a marathon.

Yeah, my impression after my first century this summer was that it's mostly just a nutrition game.  I was pretty undertrained (mileage-wise although I had a good running base this year (for me)) and I felt physically OK at the end due to a diligent attention to my sports drink.   The only part that really hurt were my wrists and my hand was numb for a day after.

I think it was actually easier than a half marathon...

Agree that effort and finish time are huge factors. A 4 hour marathon would be way easier for me than a 4 hour century. 

From a simple "completion" point of view, and century is much easier

Okay, this might sound like bragging, but it all happened when I was 20. Young and very stupid.

I was at a friend's house and decided to go on a bike ride. I headed from her house to the downtown area. I knew that there was an annual bike festival in this town. When I reached the center of the city, I saw festival markings on the ground. They were color coded and had arrows at each corner. I wasn't sure what the colors meant, but I figured that blue would be about 20-25 miles and red would be something harder. Note, I only had a single small water bottle with me.

I followed the markings and enjoyed the scenery. An hour in I realized that this wasn't a 25 mile ride. No biggie. Then, when I thought that I was nearing the end of the rout, I saw a sign welcoming me to the next county. At this point, I had nothing to do but keep following the markers.

At 3 hours I was without water and the smell of orange blossoms along the groves was making me more thirsty by the minute. I was gonna ask some kids sitting along a fence for water, but then saw that they were pumping their shot guns. My ace picked up quickly. I ultimately made it back to town and learned that blue was the century color.

There is no way that I could have survived this kind of mistake if I was running.

When the world's greatest runners can do 26.2+ miles a day, 7 days a week for 3 weeks, at a competitive pace every day, I'll think marathons are easier.

But they don't.  Nor can they.