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Thursday
Jun282007

A String Alignment Test


Here is a string alignment check that will check both your frame and fork without dismantling the bike. I must warn you that this is a little tedious to set up; I did it on my own but it would be easier with the help of a second person. Not your wife, if you want to stay married.

Turn the bike upside down and rest the handlebars on two wooden blocks or stacks of books of equal height. Squeeze the brake levers and secure them with rubber bands as shown. This will hold the wheels to stop them spinning, but still allow you to rotate them.


Measure the height of the bottom bracket shell from the ground. Now rotate the wheels so the valve stems are one inch higher than the bottom bracket front and rear wheel, and positioned at the extremities of the bike. This will be your guide to where you will place the string.

Using a piece of string long enough to reach the length of the bike and back again; start at the back wheel valve stem and thread the string inside the spokes of both wheels. Tie a loop in the string at the front tire and repeat with the other end of the string from the back to the front on the opposite side of the bike.



Pull the string tight. Make a loop at the front tire and pass it through the first loop you tied on the end of the string. Pass this loop over the front valve stem and pull tight; this will hold it in place.


Now here is the tedious part; if the sting is touching a spoke, you are going to have to untie and rethread the string. Mostly you will be inside the spokes, but in some places where the string passes a spoke near the rim, you may need to be outside the spoke.

You can turn the front wheel (Steering.) until the string is touching the tire in four places each wheel, but touching nothing else. The double string should be in the center of the bottom bracket shell, (See top Picture.) but more importantly be in the center of the down tube. A BB shell can be machined unequally, but if the wheels are central the main tubes, the frame is straight.



If your bike rides fine I wouldn’t even go to the trouble of doing this test. However, if you suspect something is off, this test will show it up. Sometimes in a crash, the front wheel will turn 90 degrees to the frame and the rider is thrown over the handlebars. In this case the front fork can be pushed slightly sideways, and the wheels will not be in the same plane.

Tolerances: I would expect the string to be within 1 mm. of the tire at any point, with the wheel central between the chainstays. My thanks to Bill Talbot for suggesting this topic.

Sunday
Jun242007

Suicide Shifters


Suicide shifters is a term I never heard until I came to the US; it is a name given to the lever operated front derailleurs used in the late 1940s and early 1950s.

I came across this rare picture from 1952 of André Darrigade (with Lucien Lauk) reaching down to change chainrings on his Simplex-equipped La Perle bike. When I started racing that same year, I used this same equipment and I can assure you there was nothing “suicide” in their operation.


The most popular lever operated front changer was the French made Simplex, (Above.) which is the one being used by Darrigade in the top picture. It simply pivoted in the center and you pushed the knob on the lever inwards toward the frame to shift up to the big ring, and opposite to shift down. Simplex also made chainrings and bottle cages (both pictured here.) The chainrings were often used with different make cranks like the Italian Gnutti or Magistroni.


Huret, (Above.) another French make, was also popular; I used this one. It worked on a helical, or screw like cam. You pushed the lever forward to go to the small ring, and back to change up.

Huret also had an interesting rear derailleur, it used twin down tube levers and twin cables. (Note: Two cables on the chainstay that also needed a double cable stop.)

(The twin levers: Left.) The large lever shifted gears, while the short lever tensioned the chain. On a smooth road, you could run the chain slack for less friction.

 

Another front changer I had fist hand experience of was the British made Cyclo-Benilux. (Above.) This one had a twist rod held with two clamps on the seat tube. You twisted the rod to shift up and down. I liked this one because I found I could reach behind my right leg and the knob at the top of the rod would be right where my hand naturally fell. Unlike the other changers that you had to reach between your legs to operate the lever.

None of these changers had return springs, they were manually operated both ways. Most of them had a simple friction device to hold it where you put it. But on most of them if the chain rubbed it would automatically knock the changer yoke out of the way, and no further adjustment was needed.

This equipment was simple, to the point of being crude, but they got the job done. We became used to it, and skilled in its operation. There was nothing “suicide” about it.

There are probably few people in America with actual experience of using these. (I would be interested to hear comments from any.) The 1970s generation probably gave them the name. They look more awkward to use that the actually were.

I can imagine in years to come, the cyclists who grew up with down tube friction shifters will fade away, and the “Brifter”* generation will then dub these suicide shifters.

Top picture from The Wool Jersey.
Other pictures from Classic Lightweights, UK.
Brifters* Combination brake and gear shift levers.

Thursday
Jun212007

The New Jersey quick release ban: My two cents


The recent New Jersey Legislation, which has led to a ban on the sale of bikes with quick release wheels in that state, is a perfect example of politicians trying to protect us and our children from ourselves, and in doing so cause more problems than they solve.

It seems the legislation calls for bicycles with quick release hubs to be fitted with some fail-safe mechanism. Whereby, when the bicycle wheels are inserted in the frame they lock in place on their own and will not fall out even if not fastened properly. No such mechanism exists and if it did it would be extremely costly to produce.

We have other safety devices in our lives that are not fail-safe. Car seat belts do not work unless you put them on. Child-proof caps on medication containers do not work unless an adult replaces the cap correctly.

Why does this piece of legislation call for a bicycle wheel, which somehow magically fastens itself? All that is needed is a solid axel with a pair of hex nuts on any bike that should never have been fitted with a quick release hub in the first place.

When Tullio Campagnolo took out the first patent and later produced the first quick release hub in the 1930s, it was born out of a need for the racing cyclist to remove their wheels quickly and easily. A simple device that has remained the same and works well for the purpose it was intended.

Why it ever made its way onto almost every other bicycle produced, including children’s bikes, is beyond me. There are two reasons why a quick release is not a good idea on all bikes. Kids of all ages think it is a huge joke to flip the quick release open on someone’s bike.

How many times have I watched “America’s Funniest Home Videos” and seen someone on a bike pop a wheelie only to have the front wheel drop out. Like your momma always said, “It’s only funny ’til someone gets seriously hurt.”

The other reason QR’s are not a good idea on all bikes. People, especially children, cannot grasp the concept of a cam mechanism tightening something. They take the nut in one hand and the lever in the other and screw it tight like a wing nut, instead of using the nut to adjust and the lever to tighten, which is how they are designed to work.

The bicycle industry needs to take care of this problem itself before we see legislation like this in other states or even nationally. Only racing bicycles and other high-end bikes need quick release hubs.

All other bikes and especially children’s models should have solid axels and hex nuts. If you can carry a repair outfit to fix flats, you can carry a wrench to remove the wheels. If you have no repair outfit, you are screwed anyway, and being able to remove your wheels quickly is of little use.

Having a quick release wheel that won’t come out when it is not fastened, kinda defeats the purpose of a quick release. A little like having a “fire proof” match that won’t burst into flame when you strike it.

Two cents worth from someone no longer connected to the bike industry, and with no personal agenda to push.

Tuesday
Jun192007

Stand-over height has little to do with the correct size frame

When I started riding in the 1950s I rode a frame that was 4 or 5 centimeters bigger than I would use by the 1970s; it was the fashion of that time.

One of the reasons for this was that aluminum seat posts and handlebar stems were fairly new and were not as reliable as today, so by riding a larger frame we had less seat post showing and a shorter handlebar stem, resulting in less stress on those items. The big difference was the frame of the 1950s had very low bottom bracket height, as low as 9 1/2 inches. Because of this frames did not seem as big.

When I arrived in the US in 1979 it was as if I had gone through a time warp and landed back in the 1950s as far as the way bikes were set up and were being ridden. American cyclists at that time were riding larger frames than their European counterparts. The problem was these frames were designed with higher bottom brackets and I started hearing the term “Stand-over height.”

In my entire framebuilding career in England, this measurement was never once asked of me, and even today I could not tell you off the top of my head what the stand-over height is for and given size of frame I built.

To me stand-over height was something a bike store would do for a customer buying an inexpensive utility bike. They would pull out a bike; have the customer stand over it. If it cleared his crotch by an inch or two it would be close enough for the use intended.

When a rider got to the level of buying a top of the line racing frame, and he bought the size that fitted correctly, then stand-over height was not even an issue. If you could not stand over your frame then you definitely were using too large a frame. However, it was not the other way round; you did not talk about stand-over height first, or even mention it.

I am amazed that stand-over height is still being talked about today, I see it crop up all the time on the various forums; I see it asked of people selling frames on eBay.

The correct position on a road bike is all about efficiency. It is not just about a low tuck aero position; it is about getting maximum power to the pedals not only from the legs, but also from the arms, transferred through the back muscles. This means having the handlebars positioned low in relation to the saddle.

The problem arises when a person wants to use a road bike for more leisurely riding, and does not want that low position. They tend to use a larger frame to get the handlebars level with the saddle. However, a larger frame has a longer top tube, so any gain in raising the handlebars is lost because of a longer reach.

Now that road frames generally have sloping top tubes, they tend to run smaller than they did prior to the late 1980s. It is also a relatively easy matter to design a frame with a slightly longer head tube to raise the handlebars, and with clipless pedals, ground clearance is not such an issue. Maybe frame manufacturers should be thinking of lowering bottom bracket height for a non-racing frame.

Friday
Jun152007

Watch out for the Right Hook

An accident so common it has a name: The Right Hook.

You are plugging along on your bicycle at about 15 or 20 mph on the right hand side of the road as you should be. A car approaches from behind; he is doing 30 or 40 mph and catches and passes you quite easily. But then the driver brakes and slows down to make a right turn.

Car brakes being as efficient as they are, he slows down quickly to about 15 or 20 mph, the same speed you are doing and as a result does not completely pass you. You are now along side the car, or a little behind the driver in his blind spot. He makes the right turn and you either run into the side of the car, he side swipes you, or in the worst case he runs right over you.

A good and careful driver would slow and stay behind the cyclist and wait until the bike rider clears the junction before he turns. Unfortunately, careful drivers are in the minority and it is really in a cyclist’s interest to ride defensively and be alert to hazards like this at all times.

First, be aware that you are approaching a turn off to the right; be it a road, entrance to a parking lot, or a driveway. Next, be aware of vehicles approaching from the rear. If they partially pass you then slow, it may be in your best interest to slow also. With your hands already on the brakes, you are ready for a panic stop.

If there is a separate right turn lane, do not ride your bike there unless you plan to turn right. Other road users will assume you are turning right, and you are asking to get hooked if you try to go straight.

I always look over my left shoulder as I approach a right turn lane and give a going left hand signal. Not an arm straight out left turn signal, but more just pointing at the road to my left to show, “I’m moving over to the next lane.”


Then I ride just outside the turn lane, close or on the lane marking. This gives vehicles plenty of room to pass on the right. You will still get the occasional joker who will pass you on the outside then cut in front of you to turn right. But I find a look over my left shoulder is the best signal to give, and most drivers will stay behind you when they see this.

Sometimes the lane markings are for straight ahead and right turn; in other words, it is not a lane designated for right turns only. In this case, I do the same glance over my left shoulder and if there is no one immediately behind me, I signal and move towards the center of the lane just so everyone knows I intend to go straight ahead. I try to do this at least 100 feet before the junction to cut down the risk of being right hooked. Once clear of the junction I move back over to the right.

Interval training is the best form of exercise, in terms of being good for the heart and for burning calories. I treat riding in traffic as interval training, slowing when caution is called for and reserving energy for when a sudden burst of speed is needed to clear a junction for example. If someone causes me to brake and slow down, it is another interval opportunity getting back up to speed.

I try to accept bad driving on the part of a few road users as an unfortunate fact; otherwise if I let every little incident upset me, it ruins my ride. I find anger on my part, keeps me focused on the stupidity and carelessness of others. If I take the attitude, “Ah well, this is South Carolina, we have some of the worst drivers in the whole country here, so this is what I should expect.” My ride is a lot more enjoyable.


Foot Note: If you live in the UK or some other country where you drive on the left, the Right Hook becomes a Left Hook. (Picture, left.) The same rules apply, just read left for right and vice versa.