Ice Biking

One of the great things about winter in Massachusetts is that it usually gets cold enough to form safe thicknesses of ice on the numerous ponds, streams, and often even the rivers -- for at least a few weeks each year. This opens a wonderful range of areas for exploration, many of which are normally fairly difficult to visit. The watery swamps become glazed skating ponds when conditions are right, and it's fun to imagine the thoughts of the beavers swimming under the ice as they hear me passing by over their heads.

Appropriate tires for my bicycle are the keys to opening up the icy playground. The only reasonable approach is to buy metal studded snow tires. Although it's possible to make them at home using screws set in heavy-duty tires, please take my word that trying that route will only result in a dangerous, failure-prone mess. My Nokian Extreme 296 tires are worth every penny in healthy fun. I have ridden hundreds of miles on them for the last three winters, and they show no significant signs of wear. I expect to keep them for many more years to come. The 296 tiny metal studs only protrude a few millimeters, so they are not much of a danger when (given my penchant for trying to push my limitations in every situation) I end up tangled in, under, or around the bike. Since the tires are fairly heavy, and could damage the roots of trees when there is no snow or ice cover, I only use them after the ground has frozen solid and there is ice on the trails. On beautiful shiny ice, the studded snow tires give great traction. Not quite like rubber on clean pavement, but more like rubber on sandy pavement. You can slide if you want to, but with a little care you have complete control.

It's a lot of fun riding out to visit the ice fishermen, circle the hockey players on the ponds, and ride circles around pedestrians struggling simply to walk on the slippery ice in areas like the Old North Bridge in Concord. But really, the most fun is exploring the streams, swamps, and rivers which become highways to solitude.

A couple of weeks ago I rode out on the Concord River between Bedford and Carlisle in Massachusetts. This was part of a 25-mile ride (mostly off-road) that day. It's amazing how fast the miles add up when you can get moving at 20+ miles per hours over the smooth ice! The photo shows my bike on the ice, looking toward some huge riverside houses in Carlisle, about half a mile downstream (north) of a public access point at Riverside Avenue in Bedford.

Enjoyable ice biking requires a fine balance between the snow cover, and the air and water temperatures over an extended period. Too much snow simply stops the bike from traveling anywhere but on plowed roads and sidewalks. Dangerous on the roads, and boring on the sidewalks! Even an inch of snow on top of glare ice can often be tricky, since it keeps the metal studs from reaching the ice, and the result is a quick slip and slide. I find it painful to ride below about 15 Fahrenheit (-10 C), so my ideal conditions call for overnight temperatures well below freezing and daytime high temperatures around freezing. An extended period of cold weather without snow cover helps to cool the water in the streams and rivers. If there is an insulating snow cover, the ground water can remain too warm to allow the streams to develop safe thicknesses of ice.

What is a safe thickness of ice? Two inches (5 cm) is a minimum on a small pond, but if there is running water or a deep pond, I don't feel safe until the ice reaches four inches (10 cm). (I remember an old article in Boy's Life magazine stating that 4 inches will support an automobile safely.) For a river with minimal current such as most of the Concord River near Lexington, I look for six or more inches. Any stretches of river with significant current, such as around bridges or narrow stretches, I simply avoid. This is not a place to take risks.

As the winter days lengthen in February, the sun delivers enough energy to melt the ice on the northern edges of ponds and streams, even while the air temperatures remain below freezing. This is especially likely where the dark soil lies directly below the ice. This can lead an unsuspecting adventurer to a sudden encounter with a cold mucky stream bed. Luckily, this nearly always occurs in shallow water, or where the ice is directly on top of the muddy bottom.

Speaking of tricky ice situations, another danger in riding on rivers is the likelihood of thin ice at points where other streams flow in. Even the smallest streams (or maybe especially the smallest streams) can contain warmer water, or salt from road drainage, which can lead to thinner ice. Watch out!

My favorite conditions for ice biking occur when a thick glaze of ice forms atop the snow. In these conditions, the whole world becomes my playground. The snow cover turns steep rocky drops into evenly graded slopes, so I can ride up areas which require dismounting in other conditions. The studded tires bite into the ice glaze, and I glide over every obstacle, dodging between trees, over the undergrowth hidden below the snow ...until I reach the evergreen forest, where inevitably the snow's glaze is thinner and I sink into the fluff...