Saturday, December 31, 2011

Skinny Tire/Small Ring

I figured there's no reason to push extremely hard right now. There aren't going to be any races around here until late April and I had already achieved a fitness goal this week, so I took the skinny tire out on an exploratory mission and kept it in the small ring.

My last ride of 2011 involved riding trails in town, and then unfamiliar territory via West Van Dorn, south on SW84th/91st to West Denton, and then east, up and over "the wall", a climb of nearly 150 feet that feels like you're going straight up.

At the top of the wall is Our Lady of Guadelupe Seminary. I had no idea this was out there. I should have taken a picture, it looks like a resort perched on a cliff, overlooking the corn.

The wind was out of the southwest for much of the ride, and then almost straight out of the west during the last few miles. I didn't have to do much pedaling on West Denton after the wall. The wind and gravity pulled me to 27mph at some point.

I have trouble grasping that it's officially January, and there's no snow on the ground.

My last ride of 2011 was 33.37 miles, at a leisurely 13.5mph pace.

Friday, December 30, 2011

May the Force Be With You

I once commented that I'm the cycling equivalent of a Mustang II. Well, after spending the last few months in the gym, I can now say with great confidence that I am the cycling equivalent of a Mustang II King Cobra.

What I'm saying is that force is no longer my limiter. I achieved my goal of doing "step ups" with 90% of my body weight on my shoulders. Six sets of six reps per leg.

It's safe to say I can make some torque (twisting force) at this point. It remains to be seen if I can convert the gains from the gym to gains on the bike. I know I need to do some leg speed work to make that happen. It's been a long time since I've gone out and just spun the hell out of the pedals. (While my cruising cadence is in the upper 80s, I have terrible form above 120rpm, a far cry from the days when I could spin out my 42x23 at 22mph.)

Why should I worry about leg speed? (About to get all mathematical up in here.)

Power = torque at speed. Most folks are familiar with the term "horsepower" when talking about cars. It's a number used to describe an engine's ability to make torque at high RPMs.

A couple of somewhat correct assumptions, correct enough for an example: A 70s Mustang II King Cobra and an 80s Honda CRX make about the same horsepower. The Mustang II's post-EPA/pre-EFI V8 makes about 200lb-ft of torque at roughly 2,000 rpm. A Honda CRX's modern multivalve four cylinder is making 120lb-ft of torque at 5,000 rpm.

Yes, the Mustang makes more torque, but at a lower RPM. The game changes when gearing is introduced.

Assuming a tire circumference of 80 inches for both cars, we arrive at 792 rpm at the tire at 60 miles per hour.

If both cars are geared to deliver peak torque at 60 miles per hour (they aren't in real life, but we can pretend they are for the sake of this example), the Mustang's final drive ratio is 2.53 and the Honda's is 6.31. This means the Mustang's engine and transmission combination is putting down 506 lb-ft to the wheels at 60mph while the Honda is putting down 757.

Having 50% more twisting force at your disposal is a clear advantage when accelerating, regardless of weight differences. Not just for sprinting, but also for climbing and battling the wind.

This is why I need to do speed work.

Monday, December 5, 2011

Ice Ice Baby

Saturday marked the unofficial start to winter in Lincoln Nebraska. It started with freezing rain followed by four inches of snow. I went for a short ride on Sunday to see what it was like. There were quite a few sections of the MoPac west that were downright dangerous.

It seems like the city was caught off guard. The residential streets in my neighborhood are pretty much one big ice skating rink, 48 hours later. The bike trails are usually clean and dry within 24 hours with a few questionable spots, but this year it's the opposite: questionable with a few clean and dry spots.

It took 42 minutes to ride to work, about 15 minutes longer than usual. I only had to get off and walk once. (Rock Island, under the zoo entrance.)

The ride home took an hour and ten minutes. The ice melted and then refroze. Stretches that were okay on the ride to work had me slithering this way and that. Coming out from underpasses was particularly dicey, as those seemed to be the slickest. I didn't take any chances on the home stretch, I walked the bike over the 27th street overpass.

While I have Nokians, I haven't taken the time to install them yet. I'll probably bring them in from the garage to warm up and swap them out tomorrow.

Things I've learned about ice biking:

  • Breathe. I've been told by a few people that your body will not tense up if you keep breathing. You are more likely to stop the bike from falling if you're relaxed. 
  • Lighten up on the saddle and handlebars. Let the bike move a little bit under you. Even side to side.
  • Don't make sudden movements. Physics is not on your side.
  • Pedal slowly in a taller gear. This helps with staying light on the saddle and handlebars. It also reduces the mechanical advantage to the rear wheel, reducing the power lost to spinning your rear wheel on the ice. 
  • Low tire PSI. You want the largest possible contact patch, but not so low that the rim is riding on the pavement. You also want the tire to deform around imperfect ice, which helps keep the bike upright.
  • Learn to lean your body and not your bike when steering. I learned this the hard way. The nearly zero coefficient of friction combined with gravity tends to pull the bike out from under you, even if you have studded tires.