North Midds & Herts '100' - purgatory on the F1/100

I was rather nervous for this event, coming so soon after riding the API-Metrow '25' yesterday.  In actual fact, my legs felt fine as I rolled over to the start line.  The event was run on a version of the F1/100 that I'd not ridden before (see map below)  Essentially, the course starts near Tempsford, then enters the A1 northbound at the Tempsford flyover.  The course turns at Buckden three times, with the southbound legs turning at the Girtford underpass, then twice at the Biggleswade North roundabout.  Reaching the Black Cat roundabout at about 86 miles, the course enters a finishing circuit along the new A421, returning to the Black Cat via Great Barford, to return along the A421 for a second passage for a finish a little way before Great Barford  In the past, I've always suffered badly from cramp in my legs at around 75 miles.  On this occasion, I was riding unsupported.Equipment-wise, I rode my Cervelo P3 with Hed trispokes.  This frame has a single bottle cage: I retained the Arundel aero bottle, which I filled with 500ml of electrolyte drink from Hi5 (free with some magazine subscription).  I also rode for the first time with a Camelbak, filled with 1.5 litres of PSP22 energy drink.  I also carried two bananas in my back pocket.  I drank from the Cmelbak at least every 3-5 miles, and had regular slurps from the bottle after about 40 miles.  So - how did it pan out? Well, my strategy was to hold a moderate pace - I was aiming for an HR of around 168-175bpm (which corresponds to upper level 2 and lower level 3 for me.  I pretty well stuck to that aim.  I also intended to sip liquid from the Camelbak and/or the bottle frequently during the race.  Unfortunately the stiff breeze that faced us on the southbound legs intensified during the morning.  I also found the riding position a bit challenging for such a long event (in part undoubtedly due to the Camelbak interfering with my Giro aero helmet's tail. In fact the southbound legs were a sore trial, the first two I was sticking to around 24-25 mph, but the third was horrid.  I found myself looking forward to getting off the A1 and onto the finishing circuit.  If only I'd known.  By the time I got onto the finishing circuit at about 86 miles, my legs were beginning to twinge with cramp.  This intensified on the second lap of the finishing circuit to a point where I had to stop and massage my legs.  And actually the A421 sections were horrendous all gently up hill with a stonking headwind.  All the riders I saw were grovelling on that section.  It was absolute purgatory, and it made the suffering on the Southbound A1 sections seem like a mere bagatelle! I'll update this with results when I can.  I did see a couple of sub 4 hour rides (3:58 as I recall). It was, therefore, rather a relief to finally pass the timekeeper's car for the second time, and noodle back to the race HQ, though with a rather disappointing 4:25:43 (I'd been aiming for a 4:15).  Oh well, win some, lose some.
View F1/100 in a larger map