Blame it on the hypnotic combination of a warm breeze and the heat haze off the road, the rows of grapevines and golden stems of wheat grass, the steep walls of the Upper Awatere Valley and the brilliant blue skies.
Alone at the front of the pack, I was in a world of my own, climbing slowly from the valley floor to the crest of an enormous hill, dreaming that this was what it must be like cycling through the South of France ... when a friendly motorist waved me down.
"Ah, John Cooper, is my name," he said amiably. "Think you're meant to be having lunch at my place .. ."
Oops. That's right. The briefing we got before heading off on this four-day mountain bike tour with the Molesworth Tour Company did mention stopping for lunch ... and morning tea as well.
Somehow in my daydreaming I'd ridden past both stops. No wonder I felt peckish.
John helped me load my bike into his wife's car and then started to laugh while he told me that we'd met earlier in the day as he'd waved to me from his tractor while mowing lawns.
As we headed back to his home, he explained that he was a true Awatere local, having lived in the valley since he was 3 on the family farm - now run by his son as a large vineyard named after the nearby Black Birch Scenic Reserve.
The lunch was superb, as always seemed to be the case here at the top of the South Island, and, in hindsight, maybe that was the reason for my over-enthusiastic cycling.
I'd spent the previous night at the historic Ugbrook Lodge, built at the turn of the 19th century, these days overlooking fields of potential gold medal grapes, and Scenic show on the road after a great night's sleep and lots of amazing home-cooked food, I was charged for action.
As our group of 12 riders plus guides Geoff Swift and Will Parsons prepared to ride, I found myself dashing about, helping less experienced riders to pump their tyres and sort out their bags. And as soon as we were out of our bus and on the road, I was off.
Fortunately, I didn't miss the first night-stop, which was a chance to stay in the old shearing quarters at Upcot Station and sample a real farmer's dinner, hosted by Bill and Nicki Stevenson and their four daughters.
Bill explained over one of Marlborough's fine wines that he is the third generation of Stevensons who have run merinos and cattle at Upcot since the late 1800s.
Obviously people tend to stick around in this part of the world. It's easy to see why.
Next morning, the road from Upcot to Molesworth Station - focal point of our trip -was a gentle 40km ride along a road snaking down a valley floor and along the sides of the massive hills.
Or it would have been gentle if it wasn't for the powerful head wind, straight off the mountains and carrying a few spots of rain, which saw most of the group complete the journey in the warm comfort of the bus. The three of us who did manage to cycle the whole way certainly felt the strain but we were quickly revived by the warm welcome at the historic Cob Homestead, in the heart of Molesworth, not to mention great Turkish bread sandwiches and hot, freshly brewed coffee.
As we travelled through Molesworth on the bus, with our guides telling us the remarkable story of this historic station, I have to confess I had a bit of a snooze, before taking to the bikes again, this time through a landscape brightened by large areas of flowering blue borage.
After that we were happy to let the bus take us up the steep climb to the top of Island Saddle, 1347m above sea level, the highest public road in New Zealand, across the Crimea Range.
But, of course, a couple of us just couldn't resist the chance to fly down the rugged gravel mountain road on the other side.
A bonus was that for this outing I was riding one of the Scott Bikes 2010 Genius machines, which has a new Twinloc system controlling both the rear shocks and the front forks with one lever, making it easy to glide over the tarseal with the suspension fully locked and, during descents like this, to glide over the roughest of rocks at lightning speeds.
It all made for an exhilarating experience and the highlight of the trip for me.
The rest of the group joined us as we rode though the outskirts of Molesworth to Rainbow Station, where we took the bus to our lunch stop at Connors Creek, then had a nice flat ride with an uphill ending at the Tophouse homestead, the home of New Zealand's smallest bar.
Next morning we were back on tarseal for the last leg of our Molesworth four-day adventure - and riding 80km into a warm head wind did make it last ... and last and last.
By the time it was all over I felt a mix of sadness that a grand experience had ended, and relief that I could give my tired legs a well-deserved rest.
Getting there: Air New Zealand has regular flights from all round the country to Blenheim.
Where to stay: Historic Ugbrook Lodge is on the web at ugbrooke.co.nz.
Cycling: You can find out about the Molesworth Tour Company's cycling adventures at molesworthtours.co.nz.
Greg Bowker travelled as guest of Molesworth Tour Company, Air New Zealand and Ugbrook Lodge.