Hardest Ride

Visited Madeira, Portugal did a meer 28 mile ride to highest point accessable by road, however 6500ft of climbing, no respite not even one of those little flat sections of about 200yrds you get on a climb. Max gradient was 29%, hardest thing I've ever done and the descent back down was fantastic. Overall a 28 mile ride that felt like a 280 mile once I got back! 

http://gb.mapometer.com/cycling/route_4221753.html 

The Col du Lauteret.  I started in 28 degrees heat in the valley at Bourg d'Oisans - at the top of the pass by the Galibier turn it was -2 and sleeting.  I did the final 5kms into a bitterly cold head wind with rain coming from all directions.  My face was bleeding at the top from the hail.

The chips in the cafe at the top were good though! 

The UBER200, start and finish in the Midlands, there and back for me was 138miles and 10,000ft of climbing, with the infamous Bushcombe Lane about two thirds of the way round - http://veloviewer.com/segment/745156 *shudders* I was buggered for about three days afterwards.

They've made it slightly easier this year, not surprising as 20% of people on the tough route didn't finish it last year  - https://www.britishcycling.org.uk/events/details/140119/The-UBER-200

I did my first Audax last year, 135 miles from Litchfield to Castleton and back and didn't bother topping up with food when I should have done (around mile 90) and gradually got slower and slower. Because of inexperience, I guess, I didn't realise what was wrong until I stopped at mile 125 and got a few chunks of choclate down me.

It was Liege-Bastogne-Liege Sportive in '14, until last summer, but is now the Tour du Mont Blanc:

http://www.strava.com/activities/353264047

As far a single days go, multi day, is another matter.

I did the Ronde Van Vlaanderen in 2014 which, on paper, should have been the toughest. However in training for that I did the Lionheart sportive. I don't think I've had a tougher day on a bike really - crap weather, no flat roads, seemed to drag on and on. Was in bits at the end! Would definitely do RVV again, don't think I'd do the Lionheart again in a hurry. 

Honeymoon, ha bet you were good for nothing not pleased new bride

A French Pyranees MTB ride in June 2011.  Headed out towards, what the French OS map said, were MTB trails.  After numerous backtracking and about 50% walking we made it onto some forest gravel road switchbacks, after which the single track started again.  A farmer had obviously been moving livestock so at one point we were ankle deep in mud and slurry.  Turning back really wasn't an option as we were beyond half way.  Got some decent riding over a plateau and then the longest downhill in christendom, which actually became quite tiring and boring, even on a full suss MTB.  We'd totally underclubbed it on food and water and still had 4 miles of road to do in blazing afternoon sun.  Thought it would be easy but it was utter misery and slightly uphill.  Arrived back at the campsite and rode straight into the nearby mountain river to cool off.  I'll never trust a French OS map again ref MTB trails!  Oh, forgot to mention that I was on honeymoon!

Single ride.... Not sure the 2015 TCR counts as a single ride, but the last 48 hours into Istanbul on 20 minutes sleep,  with two car incidents and a dog bite thrown in was a toughie. 

I rode the route of the Wiggle/UKCE "The Long One" sportive. 200km and plenty of hills. I had to take a short break on most of the last few hills - legs were shot, probably due to steep hills earlier in the ride pushing me into the red too much.  Or maybe I just didn't eat enough. I only finally committed to do it with a few weeks to go though, so my training prep wasn't great.

This year I'm doing the BHF South Downs Way in a day ride. I expect this to be the hardest I've ever done. I've ridden 37 miles of the SDW and enjoyed it but 100 miles is altogether different... Some of the hills have gradients upwards of 25%! I'd like to be fit enough not to have to walk any of it but I've got a lot of training to do to make that possible and not enough training time available.

Yes I remember the London Prudential 86! Thank goodness it was warm or it could of been a disaster for many more.

Interesting question and the replies back up my feeling that conditions on the ride have more of an influence that just basic distance and elevation.
I went through three years of strava data and based on suffer score (heart rate exertion) my toughest ride by a country mile was an off road London to Brighton ride in heavy rain through thick mud, a distance of 70 miles and only 2000 feet of elevation but I remember how unrelentingly hard it was trying to keep wheels turning through mud. For comparison, a day on Ventoux, a 24 hour dash to Paris and a couple of ride London 100's didn't come close, although the ride London 86 (one curtailed by bad weather) was my toughest road ride.

Interesting that one's 'hardest' ride is not necessarily one's longest or hilliest etc

mine was proabably biting off more than I could chew on a hilly cotswolds sportive a few years ago: 70+ miles  28 degrees and a stupidly hilly route that went down one hill only to climb up another.. Also with a riding partner who was suffering more than me - so some additional emotion to deal with too!

Fred Whitton i think. I don't even remember the last 10 miles

'Technically' it would be the Cav sportive last year. That's the most climbing I've done in a day and I'm a weak climber.

In reality the hardest ride I ever did was anything over 50 miles in my first year of cycling!! I don't struggle anywhere near as much now even if I've not done a long ride for a month or so.

Day 1 of our Mid-Wales cycle tour was what seemed a stiff-ish 40 miles from Wigmore to Llandrindod Wells. 15 minutes in I was pushing and things did not really improve, with constant climbing and descents which all seemed to end in a hairpin bend or greasy farm track preventing any impetus for the next hill. To add to our woes we took a wrong turn and started heading for Hay-on-Wye, the correction involved yet more hills. Our support vehicle was carrying our lunch but got out of phone contact as it became clear that we would not get to our planned stop on time. Fortunately we found a church right out in the wilds with a kettle, milk and biscuits for stranded travellers, and eventually made it to Llandrindod Wells to find the cycle museum closed.

As an introduction to cycle touring it made me realise that if you are doing it with friends even the worst day has its compensations, and I was pleased to make it to ludlow with the remaining 4 of 8 starters, knees and broken rims having accounted for half our number.

Suffolk 100, not because of the distance or terrain. The fact that in the first mile my neck herniated a disc and trapped a nerve. Several ibuprofen I carried on and did the 100 miles. Took several months to recover and a nerve root injection through the neck - eek!

I think it might of been almost exactly  this time last year. At the end of a weeks riding, including a fast 80 miler the day before I took on a loop in the mountains above the Tabernas Desert in the S.Spain.

The route looked meaty as I'd routed it but due to roads turning into goat tracks etc, the thing got a bit big. Started the day with the climb of Velefique and I knew from the first meter of ascent that big trouble was heading my way.

70 miles and nearly 5000m of climbing later I was in absolute bits. The Garmin was on auto pause nearly all the way up the last two climbs lol. That's the one that sticks in my mind.

http://www.strava.com/activities/293191396

on road - Yorkshire Dales cycleway

Off road - Llyn Cowlyd