Sunday, January 21, 2018

Sunday, January 14, 2018

Tour de Kurjenrahka - January 2018

Lately I've been involved in a few depressing discussions about mountain biking in Facebook. There has always been two ways most mountain bikers are involved in the sport: a) They might be interested in speed and using nature as a playground without any further actual nature interest and b) people into outdoor and nature stuff who use mountain bikes as a mean to explore the nature and outdoors. Generally a mountain biker practices a blend of those two and I'm personally quite strongly situated in the b) camp. Some people situated clearly in the a) camp have difficulties understanding arguments about taking the nature and the trails into account and this is starting to cause problems. A fall like last time, when it rained from the middle of September to the beginning of January, makes the trails deteriorate quickly and locally in the Turku area I'm convinced that mountain bikers currently cause the biggest trail damage. In these conditions riding should simply be avoided. Even the only real organisation lobbying for mountain biking, Suomen Latu, is unwilling to acknowledge the problem and do not mention it enough in the trail etiquette published. In contrast, this is recognized as item number two in the IMBA trail etiquette. There has been a number of complaints by other trails users that mountain bikers have destroyed the trails and ordinary hiking boots are not enough to keep the mud and dirt out. With the number of e-bikers rising, the situation might get a lot worse and if the current development continues, we will see limitations for mountain bikes in the future.

Due to this, I've pondered whether I should make this blog post at all. Riding the places we rode this time has great potential for causing damage to the ground if the rider doesn't care or lacks the needed knowledge and skills. And e-bikes would only make this worse. I still decided to write something, though.

There is a nice circular route in the Kurjenrahka National Park, which is possible to traverse in some situations by skis and fatbike. For skis only snow is needed, but for fatbike there are further requirements. Snow is good, since it protects the ground from the bikes. Too much snow, however, makes riding impossible, unless there is a strong enough crust. Another possibility is only small amounts of snow, which is enough the protect the ground, and ice underneath. The more ice the better, since riding on ice doesn't even in theory cause any damage. After a very rainy fall, the water level in the mires was high, which would provide perfect conditions if the ice would be strong enough. There was some uncertainty about this, but we decided to check it out. I started with JJ from Rantapiha around 15:30 a January Saturday, starting on actual trail.

The first wet opening into the mire was great and covered with strong ice.

My Surly Ice Cream Truck.

There were softer spots and good opportunities to get really wet.

Good riding on ice.

Slippery even for with 4-paw drive.

Traversing to the next rideable section. This is the trail of the ski track, which is made by snow mobiles when there is enough snow.

Rideable by searching a route with ice underneath the tires.

With cloudy weather and the sunset at 15:50, the daylight started to disappear after an hour of riding.

We entered the trail system again at the Töykkälä shelter and rode on trails to Vajosuo.

After two hours we arrived at the Vajosuo shelter. Someone had obviously just left the place, since there was a fire waiting for us. It was now about half past five, so we had plenty of time to make dinner and relax. I started with hot chocolate and toasts.

I made a tortilla dinner. Twice.

Around half past ten Toni arrived.

He had managed to get wet already.

I went to sleep maybe half past midnight in my ultralight summer sleeping bag reinforced with a ultralight summer quilt. This should have been enough for the temperature, which was a few degrees below freezing, but my toes were a bit cold, probably from being in the rather cold Shimano MT-91 shoes, which really are made for summer use, the entire evening. I should have taken my new oversized 45NRTH Wolfgar shoes, but I deemed them much too hot for the temperature.

I got up and started a fire at half past seven.

Soon Toni and JJ were also up. Toni enjoys his instant (😱) coffee.

Breakfast in the making.

Getting ready to continue.

Vajosuo was very wet and hence there was a lot of ice. No problems riding it and someone picking cloudberries in the fall definitely affects the ground more than we did.

Toni with his ITI rig. He rode the 350 mile race in 2015 and is now going for the 1000 mile race. Be sure to follow him.


Two tracks, same route.

Another section that was easily rideable with high water and ice.

The 27.5x4.5 Bontrager Gnarwhal tires work great.

A short bike pushing section later we again were on trails...

... until the next bike pushing section.

There was clearly more snow on the western mires.

There's a first for everything. This time my chain broke in two places, one of them being a chain lock. This took less than ten minutes to fix. Always carry several chain locks!

My left foot was soaked around 11 o'clock and the right foot one hour later.

This bike pushing section was quite demanding.

Crust strong enough to ride on.

Again a section with much ice.

We took a shortcut at the end, bringing to a trail that quickly took us back at the starting point of yesterday after four hours. A nice ride, but fairly demanding. The open part were mostly quite rideable with lots of ice, but the connecting sections were difficult, with great opportunities to get really wet.

Wednesday, January 10, 2018

Bontrager Gnarwhal 27.5x4.5 studded fatbike tire impressions

In December I put together Mk. III of my Surly Ice Monster Truck, with the main new thing being the 27.5x4.5" platform. I'm still lacking deep snow and crust conditions for it, but thought it would be of some interest to give my impressions so far.

The Bontrager Gnarwhal 27.5x4.5" tire has a rather aggressive pattern with big knobs, which makes it roll about as poorly as can be expected on hard surfaces. This is definitely overkill for all but the most difficult situations for summer use, at least if the rider skills are intermediate or better. Also, I think tires this coarse are a poor choice since they definitely affect the trails more that tires with more moderate patterns. I fully expected this, and will use the Bontrager Barbegazzi 27.5x4.5" tires outside the winter season, but wanted to have one tire for everything for the winter. The Gnarwhal has ready-made stud pockets and I studded the tires myself with Schwalbes's studs. With 218 studs per tire it should be good on ice and the slightly longer contact patch should give both grip and floatation.

The first ride was in around 10-15 cm of very wet snow. No surprise here, the grip was excellent and due to the big knobs the front tire didn't wash out, something that easily can happen with tire with smaller knobs, e.g like the 45NRTH Dillinger 5. I can't say I noticed the larger diameter of the wheels, though.

The next ride I had quite mixed conditions. A thin layer of mostly hard snow was no match...

... and the very slippery and uneven ice on forest roads showed that the grip with studs was excellent. Riding ordinary fatbike tires without studs could only have led to disaster in these circumstances. The tires actually worked a little better that I expected. I rode with 5.5 psi in the front and 6 psi at the back, and it felt like the tires actually conformed to the uneven ice and found grip for the studs that way. Maybe a bit surprising, since conventional wisdom tells that higher pressure would be better since it would maximize pressure on the studs, causing them to grip better. I think the grip was possibly a bit better that with Dillinger 5 in theses conditions, though Dillinger 5 clearly rolls better.

No problems on even and hard ice, either. I felt perfectly safe riding on ice with these.

The we got around 10 cm of snow. A plowed forest road, occasionally with a little snow on top of the uneven ice, was no problem.

This was colder and more fluffy snow, varying between 5 and 15 cm. On pure and even ice the grip was as poor as could be expected, since the snow hadn't yet bonded to the ice and it was thick enough to prevent the studs from gripping ice. In these condition tight turns inevitably leads to the front wheel washing out. The grip for propulsion, however, was good. Putting a little more power to the cranks caused the tire to dig down to the ice, again getting grip for a moment. The digging down is a consequence of the coarser pattern and is not a good thing in snow. The snow conditions can vary a lot, but there are conditions where a slicker tire finds floatation on top of the snow, and a more coarse tire breaks the snow surface and starts digging down. A slicker tire can have problem with traction, though. There is simply no tire that works well in all conditions.

We haven't yet had enough snow for floatation to be an issue, so it remains to be seen how the tire work in those conditions. I do think it is a good all round tire, unless you need something that rolls easily over hard surfaces. During this tests I can't say I've noticed the bigger diameter, but I assume that will be more obvious on summer trails. I'll be back when I have more miles and conditions with the tires.