People who cycle and run

[ShinyHatStand]

What would you consider the cycling equivalent of running a marathon?

DS2 has challenged himself to run marathon distance and I'd like to use this to motivate myself to extend my cycling range.
What would you consider a reasonable match?

Phew.
But I still fancy a new road bike...

.. and why not :)

If your budget doesn't stretch to a significant upgrade in road bikes then spend money on a bike fit instead, best money I spent as actually made a huge difference to comfort to enable me to ride for longer as fitness wasn't my limiting factor

How about a gran fondo? Sounds impressive, and is 75 miles

Agree about the bike, when i added a heart rate monitor to my rides it doubled my estimated calorie burn...
so I assume my ancient hybrid takes twice as much energy to pedal as whatever Strava assumed as an average.

Strava's calorie default are nuts.
Apparently I work off way more calories per hour on a gentle walk with the family than when I pedal like my life depends on it.

The equivalent is surely something that will be equally challenging for you - so your starting point is definitely relevant. If 100k is a serious challenge, then make that your aim. If its 200 miles, great. If its 50k, great.

The training will be so good for you, and a new bike is always a good motivator!

Having done both Ride London (100 miles) & the marathon I agree that a marathon is considerably more demanding on the body however time spent training is shorter (although still seriously time consuming) purely because to get up to 60/70 miles in cycle training means literally hours and hours cycling. Personally half marathons and 40/50km are more my thing and suit my decrepit body far better but I'm glad I've done both as they were definite 'bucket list' events