Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - Training for first century, long ride intensity?

I have started riding again after 20 years. 1000miles last summer went from260 down to 220lbs.( goal of 190 by end of Summer)
Riding about 80-100 miles a week. So far 450 the last two month.
Longest ride 50 miles at 85 % intensity. At end starting to cramp up.
Did Friday a all out effort for 20 miles at 18.3mph.
Saturday 37 miles at 17.5mph at 85% intensity.
Today went out for 34 miles and took it easy at 16.5mph. It felt like a walk in the park at maybe 60% effort.
All rides on same terrain,plenty off fluids.
Plane on extending the long rides by 5 miles each week.
Should i keep the long rides nice and easy or push up the intensity?
I know the mph does not mean anything, was just looking to show the difference in effort .

Thanks for you input.

Highly unscientific answer...the highest intensity you can maintain for the duration of the ride. What I found myself doing was slipping into a 'just turning the pedals' intensity - but was capable of much more. You'll be surprised how much your average speed increases by just focusing on 'not slacking off.'

What is your goal here, just be able to do a century or to do a sub 5 or 6hr century?If you are just wanting to do a century you can probably do one pretty easily right now. If you want to go faster you'll have to do some additional training. The key here is that the more/better your training the easier your century will be. Cramps are usually a symptom of a lack of hydration and/or certain minerals. In addition to proper hydration I'd suggest using a product like E-cap or my favorite, Sportleggs.

I would like to do the century in about 6 hours.
I should add that during my easy ride today i concentrated strictly on heart rate keeping it at a average of 145 where the all out ride had a average of 162. I was surprised how little the drop off in average speed at the end of the ride was and how easy it felt.
I also would like to stress i am having a lot of fun. Not following a plan at the moment. Just enjoin every ride and kicking myself about having missed out on this for the last twenty years .
Getting to know my body better after each ride.

...I also would like to stress i am having a lot of fun. Not following a plan at the moment. Just enjoin every ride and kicking myself about having missed out on this for the last twenty years .
Getting to know my body better after each ride.

Why change what you're doing? You're having fun and going a little faster each time, sounds perfect to me. The HRM is not a bad idea. Keep yourself out of the red zone and you'll have an awesome first century!

you're ready. just do it. your challenge will be laying off the gas. you have to be less goal oriented, ironically, for your 1st century. meaning: enjoy the ride. it's not a diet its a lifestyle, you know?

address your cramping with very a small magnesium supplement and regular potassium pill. salt your water. you can't really overdrink, I think the safe rule is 1 bottle per hour? so figure 6 bottles? sounds like a lot but if you're biking all day ...

I would lay off the weekday rides a week before the century.

stay out of the heat

Homebya,
Thanks for your input.
If someone told me two years ago that a century was in my future i would not have believed it.
Time on the bike will get me there!

You are at the point where you should do a couple weeks focusing on shorter intensity rather then long miles. When I mean intense, I mean 85 to 95 percent efforts uphill for 3-4 minutes. The extra strength will greatly help you during any of your longer rides. Have fun and good luck!

Highly unscientific answer...the highest intensity you can maintain for the duration of the ride.

Which is basically how "Long Steady Distance" is defined. :)

I followed a combination of suggestions above.I think it is putting me on the right track.
Went on a 20 mile groupe ride mid last week Due to a low turnout i had to ride with a group above my pace.I really had to push myself but was great fun.
Road easy a couple more days.
Sunday planed on 55 miles,a wrong turn extended the ride to 63miles in 3 1/2 hours. Felt really comfortable,one bottle per hour and two energy bars.
No cramps for the whole ride. Ran out of fluids for the last 20 minutes and paid the price 10 minutes after i got home.
I am happy and even a bit surprised with my progress.
Figured i would get bored after a couple of hours but was really able to take in the surrounding and enjoy the ride.
I am nowhere near a long distance cyclist but i can start to see the enjoyment of it.

I am nowhere near a long distance cyclist but i can start to see the enjoyment of itCycling is a great way to "run a way."

With all the inane, asinine contradictions that is everyday life- it's nice to devolve the world's perplexity in to something as simple as making the pedals of a bicycle go around.

As you are advancing in miles preparing for your first century the biggest challenge I have found is knowing exactly where a "tempo" pace is as your body adapts to the stresses of increased distance.
Please note that I said tempo, not long stead distance (LSD). That is generally about 10% harder then the pace that you plan to keep during your century ride. If you can get one, a HR monitor is a good investment to make, it will allow you to set a target HR during your workout, and hold to it.

On that note, don't just go out and go steady for 6 hours. Spice up your workouts with some speed work. It will help with the nueromuscular path ways, as well as break things up a bit.

One last thing, don't forget about your midweek rides. Tuesday and Thursday 20 mile evening rides do wonders for keeping the fitness up.

Good luck with your century, I've been in your shoes. I was 290 lbs last August, working on my 2nd double Century this year in two weeks @220 lbs.

--Colin