Back on the Bike: The First Month

I have been back on my bike for a little over a month now after at least a 15 year break from cycling. I am amazed at how quickly I got back into it; I guess a body remembers. Not that I have been a couch potato since I last turned a pedal; up until three years ago I was running up to six miles a day and my resting heart rate was 36.

I had to quit running when my hip started hurting, but I continued walking. Now when you have a resting heart rate that is just barely ticking over, walking only brings it up to the pace that most others would experience getting up from the couch and walking to the refrigerator for a beer.

The other problem with walking (or running) in Charleston, South Carolina, is that it gets brutally hot here in the summer months. It is mostly in the upper 80s or 90s with very high humidity. You can just stand still and sweat let alone do anything strenuous like running or walking.

Riding a bike I find if I get out early before it gets too hot, once I get above 10 mph I’m creating a cooling breeze, and the faster I go the more airflow. Modern cycling helmets as well as looking cool actually have a cooling effect. Made from high density polyurethane; basically the same stuff that drink coolers are made from, so what better to wear on your head on a hot day. The built in slots channel air and add to the cooling effect.

Modern cycling clothing too is wonderful; made of a material designed to wick sweat away from the body so you feel cooler. Of course you are still sweating but as long as you keep hydrated by drinking plenty of water you are fine, and it’s easy to carry water on a bike. On my walking route I had to take in series of stops at hardware stores and city parks that had drinking fountains.

My first few days back on the bike my neck hurt. I imagine the human head weighs around ten pounds. (I’ve never actually weighed one.) So naturally leaning over in a racing position means you are holding your head up and it is going to make your neck muscles sore if you are not used to it.

So why is my bike set up in a racing position? It’s the way I have always ridden and my pride won’t allow me to adopt any other way. Of course I could have raised the handlebars level with the seat and used a shorter handlebar stem, but what kind of a dork would I look wearing all the latest racing gear and sitting on the bike looking like a monkey humping a football? I may not be fast yet, but damn it I’m going to at least look fast.

Anyway the sore neck muscles went away after the first week, and so did the puffing and panting on the slightest incline. My bike handling skills quickly returned and already it feels like I had never stopped riding.

I’m riding five days a week and up to thirty miles a day. I’m only averaging 15 mph; not fast but I feel it is respectable for the first month. I can’t ride at a leisurely pace; the slightest incline or a headwind and I feel I have to ride as hard as I can. I feel that burning sensation in my upper thighs and I remember what it was like when I was at the peak of fitness. On my rest days I still feel the ride in my legs from the day before and it feels good.

I can’t imagine taking Advil for sore muscles from cycling, like the TV commercial suggests; to me that dull ache in my leg muscles is the greatest feeling in the world. But then only an ex bike racer or athlete would think that way; I guess a body does remember.

The picture at the top is me on the new Cooper River Bridge, which happens to be the biggest hill in Charleston, SC. But that’s another story that I’ll write about next time.

Shimmy Re-Visited

Speed wobbles or shimmy occur on bicycles and motorcycles because the front wheel is free to turn about its steering axis and at the same time the whole bike can move from side to side along a horizontal axis with the pivot point being the front and rear wheels being in contact with the road. Think of the motion of climbing a hill out of the saddle and you are swaying the bike from side to side.

So if the bike is swaying from side to side and the front wheel is turning from left to right at the same time the front wheel is in Nutation. Rotation is an object spinning around a fixed axis; Nutation means the axis (or axel in the case of a wheel) is also moving as the object is spinning. Think of an orbiting planet; the Earth spins but its axis also moves as it orbits the Sun

To demonstrate to motion of a front wheel in a shimmy hold a bicycle wheel by the axel in your outstretched hands (not spinning) and move your hands in the motion of pedaling a miniature bike. If the wheel was spinning while you were doing this the wheel would be in nutation. If you spin the wheel you will notice that the axel is difficult to move because the gyroscopic action of the spinning wheel is preventing nutation.

Now get someone to tap the side of the wheel as it is spinning; it will nutate (wobble) briefly but quickly return to spinning straight as the gyroscopic action dampens the nutation. So nutation is a constant and natural occurrence as a bicycle is being ridden caused by the movement of the rider pedaling the bike, side winds, bumps in the road, etc.

We do not normally notice this because the nutation is constantly dampened out, by gyroscopic action; the bike’s trail which provides a caster action keeping the front wheel straight, and the damping effect of the rider’s hands on the handlebars. However at a critical bike speed, the front wheel nutation frequency matches the bike + rider natural frequency amplifying or sustaining the nutation. And you have shimmy.

During a high speed shimmy the front wheel is not just fluttering back and forth about its steering axis but is also moving side to side in the horizontal plane shaking the head tube violently from side to side; the rider’s weight on the saddle provides an anchor point, the rear wheel on the road provides another making a pivot point for the front end of the bike to move from. Adding a pannier or saddle bag behind this pivot point will increase the likelihood of shimmy and cause the bike to shimmy at lower speeds because it gives an added sling-shot effect, especially if the load is loose and free to move.

It is a well know fact that tall riders on large frames are more likely to experience shimmy. I believe this is because the seat tube slopes backward and as the frame gets taller and the rider’s weight is more directly over the center of the rear wheel. This provides a near vertical pivot line between the riders mass on the saddle and the rear wheel on the road for the bike to shake and weave. With a smaller frame the rider’s weight is more forward with a less than vertical pivot line, making it less prone to shimmy.

Pressing your knee against the top tube will often stop a shimmy; in doing so you have dampened the shaking top tube through the muscles and tissues in you leg without actually connecting the leg to the top tube. This is also a clue that the rider needs to be holding the handlebars lightly so that you are damping the nutation rather than being connected to it by grasping the handlebars tightly.

In extreme cases if the rider is gripping the handlebars tightly the body starts to shake along with the head tube and handlebars. It becomes difficult to loosen your grip on the bars with your body shaking violently and because the shaking mass now includes your body it is much larger, higher and more fluid making the situation much worse and a crash may ensue.

This is more likely to happen with motorcycles and it has often been observed that a rider will be thrown from the bike, the bike will then stop shaking (because there is no longer a rider in harmony with the machine’s vibrations) and the bike with continue on for a while on its own before it hits something or looses momentum and falls.

An article on Wikipedia stated that frame flex has nothing to do with shimmy, but I am not so sure. Frame flex may not be the cause of shimmy but I believe it can sustain it. If the seat is not moving because the rider’s mass provides an anchor. And the rear wheel is not moving sideways at its point of contact with the road; but at the same time the head tube is shaking side to side, something has to be flexing and twisting, either the frame or the rear wheel.

Frames I built do not shimmy as a rule; so what did I do different? My bikes had a little more trail so possibly the damping effect of the extra trail helped. But I believe another factor is that all my California built frames had Columbus SP (heavier gauge) chainstays, making the rear triangle much stiffer and less likely to flex.

There could possibly be flex in the rear wheel if you consider that the upper spokes are under tension and the lower spokes are not; making the wheel likely to flex at the bottom. Also a dished wheel has unequal tension on the drive and non-drive sides. So if you have a bike that is prone to shimmy maybe think about switching to a stronger more tightly built wheels.

Most high speed shimmies occur while coasting down hill so here are a few things you can do to avoid this phenomenon. Lifting your weight from the saddle without actually standing up will transfer your weight to the pedals which are a much lower and more forward point of contact. Keep one pedal down and most of your weight on that pedal; you can switch pedals as you corner keeping the lower pedal on the outside. This will make the point of contact between you and the bike very low, but also off center of the frame.

Keep your knee lightly against the top tube as I have already mentioned, and hold the bars lightly. Many riders report that a shimmy it gets worse when applying the brakes. Well of course when you squeeze the brakes you automatically grip the handlebars tighter. So practice applying the brakes while loosely holding the bars.

Try switching your hands to the brake hoods and applying the brakes over the top with your fingers. It may take some nerve to do this if your bike is already shaking, but letting go of the bars for a split second may bring you out of the shimmy. Remember it is the connection between you and the bike that is causing the shimmy and the more connected you are the worse it will get.

Clueless

Some people selling stuff on ebay do not have a clue. Take this Fuso pictured here; listed as a “one of a kind” custom Fuso. I built just under 3,000 from 1984 to 1993 so hardly one of a kind.

Model year 2000: I retired in 1993.

Size: XL. I’m sorry the seller may be clueless but the people buying my frames are not. Extra Large will not cut it; it’s not a tee shirt. Looks like at least a 66 cm.

Frame Material: Carbon Fiber. When it is obviously lugged steel; I doubt there is one single piece of carbon fiber on the whole bike.

Starting Price: $2,300. I don’t think so. Even my custom ‘dave moulton’ bikes of which I built only 219 in California, do not command even near that yet. The going rate on ebay for a Fuso in nice condition is from $500 to $800. The higher price would be for a Lux model. That is for a complete bike with nice components; frames in good condition (Not needing a repaint.) go for around $240 to $340.

I can understand someone selling a bike and knowing nothing about it, but have they never heard of Google? Type in “Fuso Bicycle” or “Dave Moulton” and you will find all the information you need to know.

If you are selling one of my frames or a complete bike; take lots of pictures. Take close-up pictures of the lugs and seat cluster. Takes pictures of any damage to the paint, etc. Turn the bike over and take a picture of the underside of the bottom bracket shell showing the serial number and the frame size stamped there.

Take at least one good side on shot from the drive side of the bike. But don’t stand above the bike or frame and take the picture from a high angle, or the camera will distort the frame geometry. The head angle will appear steeper than it is and the seat angle shallower.

If the frame is a Fuso Lux for example; take a picture of the Fuso Lux decal on the top tube, because people will ask you, “Is it really a Lux.” Put a link to the "Bicycle" section on my website if you wish. (www.ProdigalChild.net/Bicycle.htm)

When one of my bikes is sold on eBay there is no financial interest in it for me; but I am still interested. These are my “children” and I care whether they have a good home, or if they are being treated right, and are loved.

Utter Rubbish

My Blog of July 21st on stem length has been shot down, debunked, dismissed as “Utter Rubbish.”

I failed to take into account the Competitive Fit, the Eddy Fit, the French Fit, and also the little known and yet to be accepted, Hissy Fit. I also realized that rude people may have a longer middle finger than most throwing the whole formula out of whack.

If you rushed out and bought a new handlebar stem on the strength of my Blog, I apologize. But look at it this way; your local bike store needs the business.

Let’s face it; every time a bike store closes its doors people become homeless. Forced to get out and actually ride their bikes instead of being able to stand around at the weekends in a friendly, climate controlled atmosphere, and BS about bikes.

This elbow against the tip of the saddle trick is just an “Old wife’s tale” and should be totally ignored. I was simply pointing out that there is often a grain of truth to most folk lore and that the length of forearm is relevant to foot length and therefore to the rest of the body.

Most old wives will also verify that length of the foot is relevant to penis size; which makes perfect sense when you consider that long feet prevent well endowed men from falling on their face.

Tantrums

Tantrums: That was the nick name I gave to tandems; building them was for me a love/hate thing. The problem building a tandem is in the fact that it is more than twice the work of building two single frames, but they do not command the price of two singles. So I knew I was screwed financially every time someone talked me into building one. I would cuss and swear all through the building of it (Hence tantrums.) and would promise myself I would never build another.

I will say that once the tandem frame was built I did get double the satisfaction in seeing the finished product. Time would pass and someone else would come along and ask me to build them a tandem frame; I would say “No” they would whine and beg and eventually I would give in, and the whole process would start over.

Working on a single frame whether it be brazing it or filing the lug work after; you simply hold the frame in one hand, place a wooden block around a tube and clamp it in the vise with the other hand.

With a tandem frame it is so big, heavy and unwieldy that it takes two hands to hold it; you rest one end of it on something while you let go with one hand to put the wooden block in place. Next you carry it to the vise and try to tighten it using your knee. Invariably the wooden block falls off during the process and the result is more tantrums.



There is one tandem frame that I am particularly proud of and may have actually enjoyed building it. It is the track tandem pictured here and at the top of the page and it was ridden in the 1978 World Championships by Roy Swinnerton and Trevor Gadd representing Great Brittain. Seeing two very powerful young riders get up to speeds of 55 mph. on a banked oval track is both satisfying and at the same time very frightening.

I built a few tandems when I first moved to the US in 1979 and I worked for Paris Sport; here is one of them.


Later I went to work for Masi in Southern California and in 1982 started my own business there. On doing so I promised myself I would never build another tandem.

I was asked several times but I always said “You can’t offer me enough money to get me to build one.” And no one ever offered enough that I was even close to being tempted.