MY "TEN SPEEDS"

 

 

 

MY "TEN SPEEDS"

 

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MY "TEN SPEEDS"  

FRAME SET PREARATION

INSPECTING A FRAME SET

FRONT FORK INSPECTION

REAR DROPS INSPECTION

STRINGING A FRAME SET

CENTERING THE STAYS

SIMPLE TEST - STRAIGHT

TEST RIDING - STRAIGHT

WORD OF CAUTION!

 

 

 

 

CENTERING THE FRAME STAYS

My method for straightening seat and chain stays is crude to say the least, but very effective.  So effective that one must take great care when using the frame straightening tool that I picked up at the local Dump one day.  The tool is nothing more than a four foot long piece of 2x4 lumber.  I warned you that the procedure had a crude side.

The 2x4 can be used as is or wrapped with a piece of soft cloth to protect painted and decaled surfaces.  The 2x4 is a lever and used to pry delicate bicycle frame parts this way and that.  The professional term for prying this way and that is "cold setting".  A technical term commonly referred to as bending.

Straightening the stays is a job best performed with an assistant.  Once again, if you don't know for absolutely sure what you are doing, let a guy who does know do it!  That said, this is how I put a misaligned set of stays back into alignment.

Once again, before beginning to center the stays, you must ensure that the drops are the proper distance apart (120mm or 125mm) and parallel to each other.  If the drops are not the correct measured distance, start by bending one set of stays to achieve the specified measurement.  This specified measurement is important since it will be used to determine how much each set of stays is bent in relation to one another.

Inset the 2x4 from the outside of one side of the stays, and past the opposite side of the seat tube.  This arrangement will allow for the bending of the stays towards the centerline of the frame set.  Remember, the frame being used as an example is offset to the right.  The right stays need to be pushed towards the centerline of the bicycle and the left away from the center line.  Remember the difference total was two millimetres.  This means that the string on the right side will have to be moved towards the centerline of the bicycle by only one millimetre.  But the stays will have to be bent more than one millimetre.  By going slowly and making small bends, you will get a feel for this effort.

I will make a warning at this point.  Be really careful!  If you bend the stays in too far, they will then have to be bent back again.  Repeated bending is a very bad idea and needs to be avoided.  So be gentle.  You are not trying to make the correction in a single effort.  Lots of little efforts will seriously improve your chances of success.

Now, go ahead and make the bend.  Measure after each attempt until the measured value is exactly 119mm between the drops.  When that value is achieved, turn your attention to the opposite set of stays and bend them away from the centerline of the bicycle.  Because space is a bit more limited when bending from the center out, the 2x4 lumber can be used on its side. Once again, work in small careful increments until the specified distance between the drops is achieved.

Check after each attempt to bend the second set of stays and stop when you hit the 120mm mark.  At this point in the procedure, the right stays will have been bent in one millimetre and the left ones out 1 millimetre.

With this task completed, repeat the stringing process to see what difference has occurred.  Chances are the measured value between the seat tube and each string will be closer to but not right on the money yet.  If the measured value is not acceptable, repeat the process and bend the stays again, double checking results after each attempt to bend.  With care, you will be able to center the stays in relation to the centerline of the bicycle.

Once the string is equal distance from the seat post on both sides, stop and check your work.  Pull out the drop tools again and ensure that the drop-outs are still nice and parallel to one another.  If not, square up the drops, and "string the frame again".  Though it is unlikely that squaring up the drops will change the alignment it is still a good idea to check.

Once you are finished, double check your work.  Measure the distance between the drops.  You should have either 120mm or 125mm.  Nothing else is acceptable.  Next, measure the distance from the string to each side of the seat tube.  The measurements should be exactly equal.  Nothing else is acceptable.  Check the drops for parallel to one another and if they are parallel, you are finished and your frame set is straight, just as it was intended to be.

NEXT - A SIMPLE TEST FOR STRAIGHT

 

 

 

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