MY "TEN SPEEDS"

 

 

MY "TEN SPEEDS"

 

 

 

SITE INDEX   FINDING   BICYCLES   WORK SHOP   TRADING   WHAT'S NEW?

MY "TEN SPEEDS"

 

 

"SS" BICYCLE BUILD - INTRO

"SS" COMPONENT - CHOICES

CONVERT A "SS" WHEEL

POSITIONING "SS" HUBS

"SS" CRANK/RING SET

ASSEMBLING "SS" FRAME

INSTALL - CHOICES

INSTALL - WHEELS/CRANK

INSTALL - BAR & SADDLE

INSTALL - BRAKE CALLIPERS

INSTALL - ADJUST BRAKES

RIDING THE "SINGLE SPEED"

 

CUSTOMIZED BICYCLES

BICYCLES OF CANADA

 

  

POSITIONING THE "SINGLE SPEED" HUB

Wheels and dishes!  What could the two have to do with each other? Well, every wheel originally mounted on a "Ten Speed" bicycle has a dish incorporated into its structure.  Look at a "Ten Speed's" rear wheel directly and squarely from the back of the bicycle.  You will notice that the angle, or slope, of the spokes on the drive side, is much steeper, than those on the non-drive side, of the bicycle.

Let's assume that a vintage road bicycle's rear wheel is made up of four parts - the rim, the axle, the hub and the freewheel.  True, things like spokes, nipples, bearings, and the like, are all of equal importance, in the make-up of a wheel, but they do not directly come into consideration when converting from ten gears, to one (actually its five, or six, to one, depending on the number of cogs on the freewheel).

In order to convert the rear wheel, the freewheel will be changed out, for one that is much narrower, impacting overall width of the rear hub assembly.  With the narrower freewheel installed, it will be necessary to shift the hub a few millimetres, towards the drive side, to achieve good chain-line.  Good chain-line is defined as, having the front sprocket in perfect line with the rear sprocket it drives.  That is, of course, in the perfect world.  A "Ten Speed" has a five cog freewheel, and it is rare that the bike is being ridden, under perfect chain-line conditions.  Because the front sprocket feeds power to five, or six, different rear sprockets, that sit side by side, only one rear sprocket can ever be in perfect line with the front.  All the others, are a wee bit, and a wee bit more, offset to one side, of the perfect chain-line, or the other.  However, since the "Single Speed" has only one rear sprocket to consider, why not get the chainline as close to, in perfect alignment, with the front sprocket, as you can?

Achieving the best possible chain-line, will retard wear rate, on both the chain as well as the front sprocket (commonly called the ring), and rear sprocket (most often referred to as the cog).  Reducing wear means that friction has also been reduced, and reduced friction means that the legs do not have to work as hard, to make the bicycle go.  Which means, you get there  and back, probably faster, but certainly with less effort expended.  Now is the time to set the best chain-line possible.

After rebuilding the hub, and refitting the original freewheel finger tight, install the wheel into the frame set.  Try to ensure that the wheel is centered in the chain stays.  By this, I mean, ensure the the distance, from each chain stay, to the appropriate rim face, is as close to equal, as you can get it.  As a rule, this means slide the wheel axle as far back in the rear drops, as possible.  Look, and measure carefully, to see if the rim splits the distance between the chain stays equally.  If so, your task just got a wee bit easier.  If not, you will have to make minor but easily repeatable, wheel installation adjustments, by moving either side of the axle, fore or aft, in the rear drops, to center the wheel.  Make these axle position adjustments, followed by measuring the position of the rim, between the chain stays, until the rim splits the chain stays evenly.  And, a little tip to help make this much easier...

When preparing to measure this rim relationship to the chain stays, it helps if you begin by placing a short (2") piece of masking tape, on the top of each chain stay, adjacent to where the rim locates.  Using a fine point pen, make a short line on each piece of tape, exactly opposite of the wheel rim's position.  Needless to say, take your time in making the marks, on the tape.  The marks should be made exactly in the top/center-line of each stay.  These marks will make it easier to consistently install the wheel, into the same or "starting position", throughout the wheel conversion process.  This carefully marked "starting position" can be used, not only as an installation guide, but also as a reference point to compare and measure to throughout the process of converting the wheel for "Single Speed" use.  I might add, that these marks can even be used to accurately re-dish the rear wheel, thus removing the need to purchase a proper dishing tool.  But that is another story, yet to be published.

With the wheel in this "starting position", it is time to determine how much the hub must move over, to achieve good chain line.  Again, take care to implement all measurements, to the best of your ability.  The more care you take in defining good chain-line, the better your bicycle will feel, as it lasts longer and pedals easier.

The old five, or six, cog freewheel is considerably thicker, than the single cog one to be installed.  If we just swap freewheels, the chain-line will be off by a few millimetres.  With this in mind, the entire hub must be re-spaced, to ensure that the proper chain line is maintained.  Re-spacing is achieved by moving individual spacers, from one side of the hub to the other.  I will probably be necessary to have spare spacers, of varying thickness, on hand to achieve this task.  Spacers can usually be purchased at a local bicycle shop.  That failing, go to a hardware store and try to find flat washers of an appropriate inner/outer diameter.  These will do the job, in a pinch, but proper spacers are the best way to go.

First, install the original wheel and freewheel into the "starting position".  Now select a point on the drive side rear drop, that lies in the same plane, as the center cog, of the five speed freewheel.  Carefully measure and record, the distance from the drop to the mid-line of the middle cog.

Next, remove the wheel and replace the original freewheel, with the new "Single Speed" one.  Install the wheel, to the "starting position", and measure the distance from the reference point, on the drive side drop, to the center-line of the single cog.  The difference between these two measurements, is how much the hub must be moved towards the drive side.

Next, measure the distance from one drop, to the other.  This distance should be either 120mm or 125mm.  If not, you should go back to the drawing board and double check your frame set's structural integrity.  If your original wheel slips snugly between the drops, fine.  If the original wheel is loose between the drops, or if the drops need to be spread slightly, to slip the wheel into place, then part of the re-spacing process can include ensuring that the wheel will fit easily.  Once again, this is achieved by adding or removing spacers.

Let's say that the difference in the above measurements of the two different freewheels, is 5mm.  That means, we must remove 5mm from the drive side of the hub/axle assembly, and add 5mm to the non-drive side.  It will take a bit of trial and error to get this just right, but persevere, and you should come pretty close.  It would also be a good idea to purchase a few spacers, probably available at a local bicycle store, to help make this task easier.

Once the hub is re-spaced, the wheel rim will no longer be centered, between the chain and seat stays.  With this in mind, it becomes necessary to reposition the rim, in relation to the hub.  This is a simple process, of loosening and tightening opposing spokes, until the rim is centered when compared to the hub.

The following mini-procedure assumes that we are starting with a wheel that is already true and dished for use with a five, or six cog freewheel.

As you will recall, the process of setting the wheel rim's position in relationship to the hub/freewheel combination is called "dishing".  And, the wheel we have just re-spaced the hub on needs to be re-dished, so that the wheel rim will run, in-line with the center line of the bicycle.  Believe it or not, by loosening the drive side nipples two full turns, and then tightening up the non-drive ones the same amount, you will come pretty close to having correct dish.  That is not a rule to be followed.  Just an example of how little nipple adjustment is necessary, to achieve desired results.

So, how to re-dish without a "dishing tool" at hand?

Remember those marks on the tape you attached to the tops of the chain stays?  Well, you can use these marks, with the wheel in the "starting position" to measure the rim's movement, as you loosen and tighten nipples.

With the wheel properly and accurately secured in the "starting position", measure the distance from the face of the offset rim, to the marked tape on one side only.  For this exercise we will work from the drive side.  Record this measurement for reference purposes.  The rim needs to move towards the center line of the bicycle, or away from the drive side chain stay.  This means that the drive side nipples will be loosened, and the non-drive side tightened up the exact same amount, to effect rim movement.

Now, loosen off all of the drive side nipples by one full turn, pinching each appropriate spoke, between your thumb and forefinger, to ensure the spoke is not being twisted, as you loosen and tighten.  With all of the drive side nipples loosened off, by one full turn, move your attention to the non-drive side nipples.  Tighten them up by one full turn, again pinching the appropriate spoke, to ensure no twisting is going on.

Once the nipples, on both sides, have been adjusted by one full turn, measure the results.  How far did the rim move away from the mark, on the drive side chain stay?  Consider the result and decide if you moved too far, or too little.  Loosen and tighten nipple sets accordingly.  Repeating this, simple process, will help you to re-dish the wheel and ensure that it is running parallel to, and inline with, the center line of the bicycle.

But why bother doing all of this?

As mentioned, drive chains work best, and last longer, when the sprockets they join are in-line.  Taking your time to carefully build your "Single Speed" will pay off, big time, in the end.  With each extra effort you invest, to get the bicycle built just right, your ride quality will improve.

And that is about all there is to converting an old "Ten Speed" rear wheel to one of "Single Speed" design.  There can be very little expense involved, if you take your time to understand, and then practice.  Make all nipple adjustments small, and make them even smaller, as you approach perfection.

NEXT - THE "SINGLE SPEED" CRANK/RING SET

 

 

SITE INDEX   FINDING   BICYCLES   WORK SHOP   TRADING   WHAT'S NEW?

mail@mytenspeeds.com

COPYRIGHT(2008): mytenspeeds.com