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By sherrick, October 25, 2009 8:47 pm

Everything conspired to make this a great weekend for riding. The 3^rd Annual Tourning of the Leaves was set amongst beautiful fall foliage in the vineyards, and the inaugural ride over the two bridges was warm, sunny, and hardly any wind. Pretty much everyone got to do at least one new road they had never done before and vests and arm warmers were packed into back pockets for most of the day. Just another reminder of how lucky we are to live in such a gorgeous and diverse area. Ward, Jay, and Craig took lots of pictures, so watch the web site to see when they get posted.

The Tourning of the Leaves was around 65 miles and featured a new option over Sweetwater Springs Road. It’s a beautiful, winding, one lane road along a forested creek until it kicks up for a mile and a half of steep climbing, but the view from the top is worth the effort.

Present for the ride were: June, Jack, Jay, Johnna, Joe, Joe, Ward, Beth, Andy, Tom, Vic, and Stephen.

Where the Wild Things Are

The course starts in Windsor, and rolls through the Alexander Valley, over Chalk Hill, down Westside, and River Road into Guerneville. From there, it follows the Wine Country Century back to Eastside and the start. It’s designed to be a relaxed metric century to wind down the season and to take advantage of the beautiful fall colors. We weren’t disappointed. With the recent rains, there was a lot of green in between the browns and oranges and the blue sky set it all off.

Everyone seemed to be in good spirits and on their best behavior. We kept a good pace up Chalk Hill, then regrouped and held a pace line across the valley and in to the first rest stop at the deli/market next to the Lambert Bridge. Rolling on, we see that the iron cows are still playing poker in the sculpture garden,

Who's the cow now?

and the rollers on West Dry Creek and Westside roads can still hurt. One group turned off to do Sweetwater Springs. I was surprised to find that no one else on the ride had ever done it! Just goes to show that there are always new roads to look forward to. Tom wisely figured it was best not to try it on his recumbent, and poor Andy thought he was taking the easy way around until June and Johnna took off like babes out of hell trying to be sure they beat us to Guerneville! Jay and Ward stopped near the top to take a picture, and I swear I don’t know how they ever clipped in again on that grade!

We regrouped near Armstrong Redwoods in Guerneville, took a break, then crossed over the Russian River to more one-lane roads and a couple of attention-getting climbs. Graton still smells of apples, and the Haunted House on the Hill

Say "Cabernet!"

was surrounded by a vineyard at the peak of its foliage change. There were even some grapes left on the vine for us to pirate.

Getting close to the end, and the rollers never seemed to end, until finally they did, and we were done. Some of us had to leave right away, while the rest headed over to our favorite outdoor patio restaurant for beers, burgers, shakes and salads. Can’t wait until next year!

Sunday’s ride over the two bridges was also a lot of fun. Present on that ride were: June, Jack, Joe, John, Ward, Don, Brian, Craig, Tom, Dave, Chris, Stephen, and 3 relatively new riders, Brian, his wife (Karen?) and Sean. The route follows the usual path out to the Crockett Waterfront, and then crosses the Carquinez Bridge. After a quick photo-op at the scenic view,

Everybody back up about 5 feet!

we headed south across Vallejo then into the Benecia State park with a rest stop at another drop-dead-gorgeous view looking up the Carquinez Straight. From there we left the park, crossed Benecia, and then over the Benecia Bridge, which was also a first for most of the club. It was a fun ride, nice to do the new bridge, and hopefully one we can put in the library for future Sundays.

Next weekend we set our clocks back an hour, and the sun will be setting before 5:30pm. Then it’s only a matter of time before it starts raining, but for now at least we can be happy we had one good last weekend of perfect weather and great cycling.

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By sherrick, September 8, 2009 9:50 pm

OR…Don’t think about this the next time you’re descending a winding road.

Ask any cyclist how you steer a bike, and they’ll probably tell you that it’s a combination of turning the handlebars in the direction you want to go, and leaning into the turn, right? Well, not exactly. Although balancing and steering a bike is something we take for granted, and do automatically, it’s actually a very complex skill to describe.

BALANCING

We learned quickly about balancing. If the bike started to fall over to the RIGHT, we had to steer RIGHT, into the fall to straighten up. But think about it for a moment. When your mass began falling to the RIGHT, the act of steering to the right actually exerted a force on your mass in the opposite direction, bringing it back to the LEFT towards the upright position.

STEERING

So what about steering? Next time you’re out on flat ground, try the following experiment, but make sure you’re going very slowly! You’re going to isolate the two movements, steering and leaning. First, try to steer into a turn without leaning. In other words, if you want to go left, turn the handlebars left but remain upright on the bike without leaning into the turn. Whoa! I hope you pulled yourself out of it in time, because steering LEFT just caused you to fall RIGHT. Try steering right without leaning, and you’ll fall over to the left. In other words;

Steering in any direction will actually cause you to fall in the opposite direction.

Now try just leaning into a turn, but without turning the bars. The faster you are going, the harder it is to lean over anyway, but when you do manage, if you don’t steer into the fall, you’re just going to topple over.

COUNTER-STEERING

Which brings us to the concept of counter-steering. To initiate a RIGHT turn on a bike, you actually have to first, exert a force on the bars (steer) to the LEFT. This causes you to start to fall (lean) towards the RIGHT. Now you can move the bars right, (steer into the fall) to try to catch up until you are pointing in the direction you want to go, at which point you have to OVER-STEER to push yourself back upright. If you want to turn LEFT, you start with a counter-steer to the RIGHT, etc.

THE RULER ANALOGY

Imagine what would happen if you were trying to balance a ruler upright in the palm of your hand. If the ruler starts to fall over to the right, you have to move your hand to the right to catch up to its fall, and then overshoot it by a bit to bring it back upright. Now suppose you have the ruler under control, and you want to move it over to the right. If you start moving your hand to the RIGHT, the ruler is just going to fall over to the LEFT, so that won’t work. In fact, what you have to do is first make a small movement to the LEFT, which causes the ruler to fall towards the RIGHT, and now you can move your hand right until you reach the point you want to be at. So then, how do you stop the ruler from moving or falling further? You over shoot the fall to the right, which pushes the mass of the ruler left, and hopefully brings it back to upright.

SUMMARY:

When you want to make a turn, you have to:

• First counter-steer in the opposite direction, which causes you to fall (lean) in the direction you want to go.
• Which then allows you to bring the handlebars around and steer into the fall until you are pointing in the desired direction.
• Now to bring yourself out of the turn, you have to over-steer even further into the turn, which will push your mass opposite and bring you upright.

Have fun on those hairpins next time out!

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By admin, September 7, 2008 7:03 pm

by Stephen Herrick

Here’s a good one to amaze your friends at rest stops

Kneel down next to your bike on level ground, and hold it upright. Turn the cranks so that the pedal on your side is at the very bottom (6 o’clock) position. Of course, the pedal on the opposite side is at the highest 12 o’clock position. Grab the pedal on your side.

Now you’re going to gently pull straight back on the pedal, (towards the rear of the bike,) but before you do, ask yourself these two questions: Which way will the pedals rotate, and in what direction will the bicycle move?

Of course, pulling back on the pedal at it’s lowest position should rotate the cranks in the normal forward pedaling motion, sending the bike forward, right? Try it, you might be surprised.

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By admin, September 7, 2007 6:41 pm

by Stephen Herrick

Suppose a Diablo Cyclist wanted to train hard enough that he/she could start at a point exactly 15 miles from the summit of Mt Hamilton (say at Amy’s Rancheria,) ride to the top, and then return exactly the same way and have an average speed of 15 miles per hour upon his return.

He/she goes out as hard as he can, and checks his cyclometer as he makes the turn at the observatory before heading back down. He’s got an average speed of 7.5 miles per hour so far.

At what average speed will he need to ride the descent back to the start in order to finish with his target goal of 15 miles per hour for the compete out-and-back?

Well, it’s a trick question really. He can’t get his average up to 15 miles per hour unless he can teleport instantaneously back to the start.

Here’s the deal. Average speed is determined by the distance you travel, divided by (per) the time you take to do it. However, if you average ½ of your target speed over ½ of your distance, you use up all the time you’ve allotted yourself to complete the entire trip already.

Plug in some numbers, and it gets easier to see. It’s exactly 15 miles from the start to the summit, so an out and back would be a total of 30 miles. If you want to finish the whole round trip with an average speed of 15 miles per hour, you have to complete the ride in 2 hours. But if you average 7.5 miles per hour for the first 15 miles, then you’ve already taken two hours!

Or, for the mathematically inclined, d (distance) / t (time) = v (velocity or average speed)
Flip that around you get, d/v=t.
But, 1/2d / 1/2v also = t.

Try something actually doable for all you daredevil descenders. Say you start at the same point 15 miles from the top, and you’ve got the same goal of 15 mph average, so you have 2 hours to complete the ride. You check your cyclometer at the top and you’ve got a respectable 10 miles per hour.

Okay, it took you one and ½ hours to climb to the summit (15 miles at 10 miles per hour, congratulations.) Now you’ve got to make the return 15-mile trip in ½ hour. That requires an average speed of 30 miles per hour. Watch it on the hairpins!

But say you get to the top and you’ve got an average of 8 miles per hour. Well, riding 15 miles at 8 mph means it took you 1 hour, 52 minutes, and 30 seconds to get there. Remember, to average 15 mph you have to complete the trip in 2 hours, so now you have only 7 and ½ minutes left to get down. Let’s see, 7.5 minutes to go 15 miles would require an average speed of 2 miles per minute, or 120 mph! I don’t think you’re going to make it.

The moral of the story is; you can almost never recover your average speed after climbing up a long hill merely by descending the other side.

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By admin, September 7, 2006 6:48 pm

by Stephen Herrick

Ever wonder how many pedal strokes you would have to turn if you rode 100 miles? (Come on, admit it, you think about it all the time…) Well, if you’re on a bike that shifts gears and can coast down hills, then you would need a wheel rotation sensor to count it out for you, or the best you could do would be to estimate. However, if you’re riding a fixed gear bike, then you can actually calculate the answer pretty accurately. You’ll need to do some conversions, and you’ll need to understand something about gear ratios and gear inches, also called virtual wheel size.

Your gear ratio compares the relative sizes of your front chain ring and rear cassette, and is easily calculated by dividing the number of teeth on your front cog by the number of teeth on your rear cog. Since the chain ring is attached to the crank set, and since the rear wheel is spinning at the same speed as the cassette when you are not coasting, then the ratio of pedal strokes to wheel rotations will be the same as the gear ratio. In other words, if a roadie is in her big 52 ring in front, and in her 13 ring on the rear cassette, then 52 divided by 13 = 4, so her wheels will be rotating exactly 4 times for each pedal stroke.

To understand chain inches and virtual wheel size, picture an old penny-farthing; the antique bike where the rider was perched up on top of a large wheel with the pedals mounted directly on the hub of the wheel. These wheels grew to about 60” in diameter, or about 15 and ¾ feet in circumference. Each pedal stroke turned the wheel around once, and so the distance that the bike traveled forward was exactly the circumference of the wheel. Calculating chain inches/virtual wheel size of a bike with cogs and chain is like trying to figure out how big the wheel on a penny-farthing would have to be in order to move you the same distance forward with each stroke. Figure out your gear ratio, (teeth in the front divided by teeth in the back,) and multiply that by the diameter of your tire in inches. So if the roadie in her 52 / 14 was on a standard tire with a diameter of 27.6 inches, then her virtual wheel size would be (52 divided by 14), times 27.6 inches, which equals 110.4 inches, or a little over 9 feet high! Her distance forward per pedal stroke would be the same as the circumference of the wheel, (Diameter X Pi = Circumference) so 110.4 inches X 3.14 = 346.7 inches, or 28 feet, 11 inches.

Okay, back to the fixie and his century. Let’s say he’s using a pretty standard set up for a fixed gear bike with a 42 front chain ring, and a 17 back cog. 42 divided by 17 equals a gear ratio of 2.47 wheel revolutions per pedal stroke.

Now take the gear ratio of 2.47 and multiply it by the circumference of the tire, and you’ll get how far the bike moves with each stroke. A standard 700 mm diameter road tire converts to a circumference of about 7.2 feet.

2.47 times 7.2 feet = 17.82 feet. That’s how far forward a fixie goes with each stroke.

Using 5,280 feet in one mile, divided by 17.82 feet per pedal stroke = 296.29 pedal strokes (revolutions) per mile. Multiply that by 100 miles and you get:

29,629 turns of the cranks to ride a fixed gear bike for 100 miles!

Summary:
Gear Ratio = Front Cog divided by Rear Cog
Chain Inches, or Virtual Wheel Size = Gear Ratio X Wheel Diameter in inches
Distance Traveled per Single Pedal Revolution = Gear Ratio X Wheel Circumference
Pedal Revolutions per Mile = 5280 feet/mile divided by DT/SPR (in feet)

If you like this kind of thing, and you want to see what the numbers would be like on your bike, follow this link to a great web site for calculating just about any gear set up.

http://www.jbarrm.com/cycal/cycal.html