depends very much on the kind of terrain. if there are a lot of hills or even
mountains it could be a problem. on flat ground i think its fine.
the other thing is that if you start riding this distance 6 days a week you soon
will be an extraordinary person and it will be easier day after day!
i ride 25-40 per day (the 25 is the normal commute round trip, the rest is for pleasure or for errands) on a fixed gear. the bike's not exactly light and i'm almost always carrying 5-15 pounds of stuff.
i'm pretty ordinary, i guess. sorta fit, but still rather stout (if i didn't drink so much beer, i'd merely be burly). i ride to work, ride home, ride to the grocery store (although I take the SS with the trailer for the big trips), ride to the coffeeshop, the library, the bookstore, the liquor store, the movies, etc. sometimes, we just cruise.
if you're going to ride that much, just make sure the bike's comfy and you've got the gearing selected so that you spin a bit more than you grind and so that you can climb whatever hills you've got to climb.
Let me armchair quarterback this one after I eat a Quarter Pounder and drink a beer.
Heres a quote from Road cycling skills by Pete Penseyres, winner of 1986 RAAM:
"My regular one way commute was 30 miles, and I was adding 10 miles on my way in, then riding 60 or 70 miles on my way home.I was getting in 110 miles a day and on weekends I would do a double century on Saturday and another on Sunday. So I was doing 1000 to 1,100 miles a week."
The Wrench posted the other day saying where are the real riders, that's a real ****ing rider there.
Single speed? No different than a bike with gears because you can coast and use your brakes instead of your legs going down hills. If the 50 miles was relatively flat it wouldn't be any different than a geared roadbike. Gearing would then determine how long it would take. So if you had something nice and easy like 42:17 then it would take you maybe 4 hours to go 50 miles. But if you broke it up into two 25 mile commutes then yeah, it would be easier, say 2 hours to get to work and 2 hours to get home.
But then after a month of 300 mile weeks would you be an average rider? I don't think you would be in average condition.
The more I cycling, the more heavy I am. My weight has increase from 76 to 78.5 kg after my 25 km commute everyday. If I am doing 250 miles per week, I will be like Block Lesnar ! Just kidding...hehe
Wow, if you're pushing 3:1 gear ratio up a 5% grade for 25km, I'm not surprised that you're getting heavier. I'm sure you muscles are growing and they're much denser than fat. Also, if I have this correct, above 60-65% of your maximum heart rate your body can no longer derive fuel from fat ... It's too hard/slow to metabolize under such a demand.