Can I run 2:50 in 3 weeks?

Yes. Don't go out too fast.

Gonna be tight. You've got a better shot at 2:52...

Hard to tell from the info given. I would think that you would be in the ball park from your 10 miler, but 18 mi at 6:50 shouldn't be that hard. You might be long on speed, short on endurance.

FWIW, I think I'm in better shape now that I was when I ran the 18, which was only 4-6 weeks into actually running almost every day.

Got a bit of a mixed bag of responses, so I'll give it a bump to see if the night owls have any opinions.

FWIW I ran a 10-miler in 59:10, and 2 weeks later did a 2:50. On similar weekly mileage, and a little longer long run. Maybe you are close.

2:55 should be comfortably in range. The rest kind of depends on pacing and how well you can run through the cramping and pain of the last 10K. If you function well on hate you've got a shot. If this is your first try at the distance I imagine you'll come up short.

Is this your first marathon? Any actual race times not races run like workouts? PRs, even if old?

No chance in hell. 2:55 may work though.

Why do you go for an *easy* 20 miler? 10 miles easy + 10 miles at MP is the correct workout.

Alright, I'll do the 10 easy + 10 at MP this weekend.

PRs are from college. Haven't really raced this year other than a 17:15 5k.

PRs 2007-2009:

800m - 1:54

Mile - 4:16

3k - 8:53

5k - 15:12

10k - 32:20?

Half - 1:15:23

I've done 2 marathons, after graduating from college and falling out of shape. 2:58 and 3:01.

I think people are probably accurate that 2:50 is a bit of a stretch, but we'll see how my long run goes this weekend. I ran 10 at 2:50 pace last night.

I think you are headed for another 2:58 or 3:01 unless they were run in the mountains and this fall you are running Chicago and the weather is perfect.

At 50 mpw and 25ish years old I'm surprised you can only run 17:15 for 5k...

With those PRs you may surprise us. For Saturday, ease into MP, the point is to flow as easily as possible all the way. Economy is everything in marathon. Hydrate well and bring some gels. Good luck.

The 17:15 was earlier this year after a 4 month hiatus and a month of running 20-30mpw. I don't train year round because I work a sh*tload of hours half of the year. If I had to guess, I'd say I'm around 16:30 shape now.

I'm in markedly better shape now than I was when I ran 3:01 last year. But, the course isn't a cupcake by any means. I know I can break 3:00 if I don't go out too fast. I think I can dip under 2:55. But it's hard to tell with marathons. I didn't think I was in 3:01 shape last year so I'm hoping to surprise myself again this year.

I'm going with the consensus here that 2:55 is reasonable, but 2:50 is a long shot. My pre-marathon 10 miler was 56:20 and I did an 18 miler at 5:48 pace, both in training. Ended up dying in the last 8 miles of said marathon, finishing in 2:44 (only 6:16 pace). If this is your 1st marathon, I wouldn't go out any faster than 1:24-1:25 at half. I was only running about 50-60 mpw for this marathon also.

Thanks everyone. Barring a lights out long run this weekend, I think I'll probably go out in 1:26-1:27 and see what happens from there. I've not hit the wall in my other 2 marathons, but I went out pretty conservatively on both of those as well.