Wednesday, November 26, 2014

Thanksgiving hours and holiday special

HC will be closed for the Thanksgiving holiday weekend, Thursday, November 27 thru Monday, December 1. We will get back to normal hours on Tuesday, December 2. I am more than happy to take orders and answer questions during this time via email during this time. hiawathacyclery at gmail

Don't wait in line for hours like on Thanksgiving and Black Friday for deals. You can get all your deals here at HC. Buy any gift certificate between now and December 31, and I'll add 15% to it. For example, you spend $100 and get a gift certificate for $115, or spend $1000 and get a gift certificate for $1150. You can order this by email or phone, and I can mail it to the intended recipient.

Thursday, November 20, 2014

Are fat wheels heavy?

I think most smart bike people will acknowledge that fat tires have superior traction and flotation on sketchy surfaces, in winter conditions, etc. But the tradeoff is that they're so heavy and slow!

Thirteen years ago, the University of Minnesota decided to grant me a master's degree in geophysics, and I figure it's finally time to apply that credential to some useful purpose. So why not start by measuring something. Here's a 120tpi Dillinger 26x4" on the scale:
The scale reads 1352 g with packaging included. Add in a Q-tubes 26x2.4-2.7 superlight tube and a standard Marge Lite rim, and we have a tire/rim mass of approximately 2.28 kg.

For comparison, consider a more "typical" winter bike wheel. A Schwalbe Marathon Winter 29x2.0 studded tire is listed at 1265g. On a typical 520g rim with a typical 220g tube, this typical winter wheel weighs in at just over 2.00 kg.

But the acceleration of a wheel with an applied torque is not quite as simple as a basic mass comparison. We also have to consider the size of the wheel, since mass farther from the center of rotation is harder to accelerate. The important physical quantity here is moment of inertia. The lower this number, the faster the wheel accelerates under a given torque. Most cyclists prefer a lower value for moment of inertia, though having a higher value increases rolling momentum, which is desirable sometimes. If I assume that the effective radial center of momentum of each wheel is in the center of the tire (halfway between the rim bead seat and the outer tread of the tire), the 29" wheel has an effective radius of approximately 0.340 m. The fat tire 26" wheel has an effective radius of approximately 0.330 m.  The formula for moment of inertia is I = m x r x r. So square the radius and multiply by the mass. For the fat tire 26" wheel, the value of I is 0.24 kgm^2. For the 29" wheel the value is 0.23 kgm^2. These are about double that of a typical high-performance road racing wheel.

I consider these two inertia values to be effectively the same, given the simplifying approximations I made. But the fat tire is widely regarded (by armchair experts) as heavy and slow, while almost nobody thinks to comment on how heavy and slow a typical 700C/29" winter wheel is.

Note that I'm assuming that the mass of a hub and spokes don't contribute to the inertia calculation. Assuming the same hub mass, the 26" wheel has a slight advantage because the spokes are shorter and lighter. But the more important mass is further out on the wheel. That's why I just consider the mass of the rim, tire, and tube. Also, I'm not considering the effect of tire rolling resistance or aerodynamics. My general sense is that a high-quality fat tire inflated to an appropriate pressure has lower rolling resistance than a Schwalbe Marathon Winter, but the skinnier tire has lower aerodynamic drag.

Friday, November 14, 2014

Winter bike stuff

This week, winter set in a little earlier than usual. Given the 10-day forecasts, and the date on the calendar, we probably can't expect much of a break from cold and ice and snow anytime soon.

So I've added a few cold weather items to my Ice Cream Truck:
First, I added 45NRTH Dillinger 26x4.8" studded tires ($250 each or $450/pair). They are costly but worth it, in my opinion (similar 45NRTH tires also available in 26x3.8, 29x2.35", 700x38, 700x30). I missed out on the limited supply of studded fat tires last year, which was unfortunate given the combination of cratered/rutted ice-pack and deeper snow along my commute route for six months of winter. I opted out of bike commuting a lot because it was simply too dangerous on the ice on my fat bike, and too difficult in the snow on my skinnier tire studded bike. So this is the best of both worlds.

Second, the roads get pretty sloppy in places, so I added PDW "Dave's Mud Shovel" fenders to keep myself from getting excessively splattered. I used two front fenders ($18/ea), one on the downtube as intended, and one zip-tied under my Old Man Mountain rack ($135 for the ICT version).

And third, the 45NRTH Cobrafist pogies. These are fairly expensive at $125/pair, but they are a bargain compared to most comparable options, and designed really well. The design allows lots of unencumbered hand movement inside, plus convenient pockets and vents accessible from the inside. The idea of pogies is to allow the rider to ride bare-handed or just wear a thin glove inside the pogies, which means no dexterity loss for shifting and braking, compared to wearing big chopper mitts or lobster claw mitts.
And finally, lights. It gets dark here at 4:30 PM, so having lights that function in cold temps is an essential. I'm running dual NiteRider Lumina 750 lights ($140 each). Unlike alkaline-battery lights, these don't seem to fade in the cold. One is plenty, but having a backup light isn't a horrible idea.

Wednesday, October 29, 2014

A new adventure on the calendar

I've been married to my wife just over a year now, and we now have a baby together. It's honestly been wonderful. But being in a happy, secure relationship, then going through a challenging pregnancy, followed by caring for a newborn that doesn't often let me get enough sleep... Well, that situation has not exactly been good for my eating habits, and my waistline and new chins tell the tale. I've gained about 40 pounds in the past 13-14 months. I took half-assed measures to take the weight back off, but of course, I still continued to gain. Once the baby came and got settled in, I've begun to have more time to ride, which feels good, but those extra 40 pounds are obvious when I'm trying to pedal up hills.

Anyway, last week I read about the Tuscobia winter ultra. On a whim, I signed up for one of two remaining slots to race/ride the 75-mile option on New Year's Day 2015. I have never been more than moderately athletic, and as I already described, keeping my weight under control is a challenge for me. But having an event on the calendar has really focused my effort. I immediately reverted to a past strategy that has yielded success: low-carbohydrate diet. I stopped sneaking sweets (including fruit) and pastry and anything made of grain. I've lost 5 pounds already. I'm probably not going to lose 40 pounds in two months, but I can probably lose 25 and get back under 1/10 of an English ton in time for the race.

I'll try to keep the HC blog updated about my weight progress. Also potentially of interest: I'll also do some posts on my gear choices and training. 

Tuesday, October 28, 2014

Tis the season

After an exceedingly pleasant Summer-ish Fall, we are finally getting to that time of the year. Luckily, we don't yet "need" fat tires, studded tires, or fat studded tires, nor do we require any specialized clothing or extraordinary cold-weather toughness (by Minnesota standards). For the most part, we can still just hop on our bikes and ride. But it sure gets dark early now, and this weekend we will all set our clocks back an hour, so it's gonna be dark by 5pm next week. If you're going to keep riding, and you really should keep riding, you could do worse than investing in some good lights if you don't already have some. I see a lot of unlit cyclists out and about, and if I could think of a way to do it without creeping them out, I'd approach them and offer to provide them with free LED blinkies (they don't cost much). Honestly, riding unlit is so dangerous. If you do ride at night a lot, something better than cheap blinkies is probably in order. We like the NiteRider Lumina series lights, but you really can't go wrong with most of the lights on the market.

I used a second stem and a cut off chunk of handlebar to mount two Lumina lights (a 700 and a 750) on my bike. One is probably enough, but I work for the Department of Redundancy Department. I have a helmet mount, too, so when the situation warrants it, I can detach one of these and put it on top of my head in 2 seconds.

Here is a pic from some trail riding last week with my riding buddy. To protect his privacy, let's call him "Cheesecake Jake". Trust me, a nickname like this is how legends are born.

And here's my bike midway across the Marshall/Lake bridge a few nights ago (just one light on).

Taillights are important too, but they don't need to be fancy. We like various versions of the Planet Bike Superflash. They are inexpensive ($20-30 ish), bright with an irritating (good) flash pattern, have a sensible/sturdy mounting bracket, and the AAA batteries last a long time.

Tuesday, October 21, 2014

Ice Cream Truck commute

I was all set to do some kind of sentimental "Ode to Winter Cycling" post, but Fall has been amazing this year in the MSP. We have had a nice slow descent into lower temperatures, and no hints of early winter yet. So I'm going to stay in the moment. This is as good as it gets.

Since I got my new Surly Ice Cream Truck a few weeks ago, I have stopped riding other bikes. My Surly ECR is on loan to a friend, and my "road bike", a hot-rodded Torker Graduate, is mothballed for the season (unless someone wants to buy it). So the ICT is my only bike, for now. Eight years ago during the fat bike stone age, I would tell people that a fat bike was a sort of luxury for the person who already owns 7 bikes and wants something "different". And now in 2014, here I am thinking that I feel pretty happy with the ICT as my only bike. This is partly because fat bike technology has improved dramatically in the past 8 years, and partly because my perception about what a good fat bike can do has gotten broader with experience.

Anyway, with the sun shining and temperatures still mild, I left a little early for today's commute. A few minutes after leaving home, I ducked around a long-abandoned, rusty steel gate onto a weedy, cracked-up old road, down the bank, and under a bridge to the river.

By the way, the Surly Bud is the ultimate fat bike tire (unless you need studded or skinnier than 5"). Bud was originally marketed as a front tire, with Lou marketed as its companion rear tire. I now run Bud front and rear. Bud seems faster than Lou with no meaningful loss of rear traction for us mere mortals.

It was mostly smooth riding, but I had to go into the water to get around some fallen trees. I got two soakers, but I didn't care.

I was eventually "forced" to ride in the woods. The nice thing about the ICT is that I don't really need a buff trail. I can just meander through the woods, around and sometimes over logs and other debris. Luckily this spring's flooding hauled away a lot of those obstacles, and left large swaths of open riding. It's particularly lovely down there with the yellow leaves.

I am lucky to be able to tie so much "wilderness" riding into my commute. It improves my mood all day.

Friday, October 17, 2014

Become a connoisseur of studs

I bought my first studded tires 11 years ago: Nokian Hakkaplitta W106 (they have 106 studs) in the 700x40 size. If there were other decent studded tire options back then, I didn't know about them. Those Nokians were heavy and slow and not much fun, but they did allow me to commute through the winter on streets and bike paths without any serious crashes. I also learned that winter riding involves a huge variety of surfaces conditions, and no tire is perfect for all of them.

Back when we had few options, we didn't have much need to scrutinize our studded tires. But now, we have lots of choices, and we can spend at least a few minutes over-analyzing. The classic type is shown here:
The top tire here is a Nokian Mount and Ground. The bottom tire is a Schwalbe Marathon Winter. The Nokian has a more open tread profile with tall lugs - this combination gives a good bite in snow, while being less likely to get snow packed into the tread. The Schwalbe has a lower profile tread and the lugs are more closely spaced. The benefit here is that the tire should roll more smoothly on pavement and hard ice. The common view among those who've tried both is that the Schwalbe rolls better/faster despite having more studs. If you are mostly riding paved streets and trails that are plowed but icy, the Schwalbes will probably be faster and more fun to ride. The studs on both tires have a square point with a sharp corner to dig into the ice. This type of stud works very well when new, but its performance diminishes as the corners get rounded off. Here's what they look like worn:
Don't pay attention to the rust, which is both inevitable and irrelevant. This is a Schwalbe Snow Stud, which was actually similar in tread pattern to the Nokian above. This tire started with square studs, like above, but it endured a couple winters of wear. It's subtle, but if you look closely, you can see that the sharp corners of the studs have been worn down and are now slightly rounded. It still works fine on smooth ice, but this tire failed me when I hit some uneven ice (common around here after snow and ice and car slop have been compacted together into rutted, cratered surfaces on the streets). I can't prove it at the moment, but I think I could have rolled that ice hump without an unplanned dismount if the studs were new and sharp-edged.

Here's what a 45NRTH Xerxes looks like. These tires have been in stock at HC since last year, so I'm not sure if this is still representative of the current Xerxes tire.
These tires are pretty lightweight and have a nice supple casing, and I would imagine that they roll much better than any of the tires I showed above. But the downside is that there aren't many studs, and the studs are not very sharp-edged (pre-worn?). I view this as a tire for road riders who wants to ride in spring and fall when the streets are clear, but have some control when they hit black ice. This would not be my first choice for serious winter commuting in Minnesota. But since these are 700x30, which is skinnier than most studded tires, these might be your only option if your bike doesn't have adequate tire clearance for something bigger.

Finally, this is the tread of a 45NRTH Dillinger (26x4" or 4.8"), but it's pretty similar to the 45NRTH Nicotine 29x2.35", which, in my experience, is an amazing tire.
These tires have a new concave stud style. The idea here is that as the stud corners wear, there is no center section to form the apex of a rounded dome (see the rounded/worn Schwalbe studs above). This means that the studs stay sharp even when they get worn. The sleeves of the studs are aluminum to save weight, while the points are wear-resistant carbide steel. These tires are expensive, but I believe they are the best available today. If you have a fat bike or "29er" to ride in the winter, these tires will handle a wider variety of winter conditions than any other winter tire on the market.