georgehoward said:Originally posted by Tom Keats I'm not suggesting any answers. I'm just asking a couple of
questions, myself.
Could this effect be because the wheels aren't tracking properly -- say, if a rim is off-centre in
relation to its axle? And if so, would some difficulty in riding a straight line no-hands also be
a symptom?
It certainly could be caused by various misalignments, but I believe it can happen with a
perfectly straight bike. Recall what I said about our tandem; I lean one way, my wife leans the
other. I've known people who always wear out one particular side of their saddles, no matter what
bike they ride.
There are ways to check the alignment of a bike. One way is to take a long straightedge and hold it
alongside the wheels, about six inches off the floor. Assuming the wheels and tires are identical,
the straightedge should touch in four places.
Another way is to carefully walk the bike down a tiled hallway (or other flat surface with accurate
lines). Hold the handlebars one-handed at their center and walk at least ten feet, being careful to
keep the bike balanced and the front wheel exactly on a line. Then stop and see if the rear wheel is
exactly on that line.
Much quicker, but not nearly as accurate, is to ride though a puddle and beyond, riding straight.
Then see if you leave one track or two side-by-side ones. And yes, the bike will probably pull to
one side when ridden no-hands.
If you suspect your wheels are not symmetrical, measure the distance from the front fork blade to
one side of your wheel. Take the wheel out and reverse. You should get the same measurement.
You can get a good idea of rear triangle alignment with a string run from a rear dropout, around the
front of the head tube, back to the other dropout. It should clear each side of the seat tube by the
same distance.
Fork alignment is tougher. AFAIK, the only way to get good measurements is to take the fork off the
bike and lay it on a flat work surface, then measure carefully.
--
Frank Krygowski