From post by spatten (and SOP):
**with a few comments**
There are two things that I believe create more left side wear when sport riding:
1. It's harder to turn and accelerate aggressively when you have your weight on the throttle hand. This would be along a continuum for different skills or aggressiveness. It takes much more skill to work the throttle well when turning right. The exception is racers with really strong stomach muscles and grip with their legs, and not too many of us fall in that camp.
**WTF...Either I am highly skilled and zen-like in the corners...or this is just not so. REALLY?
Or it's the monster abs thing. Seriously, I concentrated on this on the way up the hill last night.
Dark, road nearly empty, 20 miles of winding and climbing goodness. I found that I have NO
TROUBLE AT ALL cornering with just fingertips on the bars. Literally. Both directions, variety of
speeds, cambers, road surfaces, etc. No arm wrestling, no ab pump, no problem. It seemed to
be completely symmetrical. Seemed. Me. One trial. I just don't buy it.**
** Oh, and dragging the pegs often, on recently new Pirelli Angels, 55 on the back. Bags, no top
box, 210# plus gear, using both upward lanes. Yes, I was hauling pretty good. For a fat guy.**
2.
Quote
Late Apex is a late Apex, regardless of direction. Riding on the road I hold outside to the point I can see my exit point/line.
Still sticking with road crown
**This if from SOP. I have to agree on the apex thing. Straight, if possible, until I can see the exit.
At least trailing the throttle and cautious until I can see all the way through the corner. (SOP is
the first rider I have met in a long time who has longer time on the road without a crash, BTW.)
Not only good on tires, good defensive technique all around. **
If you take the same road curve in both directions the left turn is a bigger arc (radius) than the right turn, in the US. You go faster in larger radius turn than a smaller radius turn and it's harder on tires. You apex at a higher rate of speed if the curve radius is larger, all other factors being equal.
** HERE is the reason for this long-winded post. Velocity IS NOT harder on tires. Physics Fail.
ACCELERATION (equivalently, FORCE) is harder on tires.
Physics lesson: Acceleration is a VECTOR (amount AND direction), so we can think of it as being
divided up into two components: 1) acceleration that changes speed; 2) acceleration that
changes direction. 1) points directly in the direction of motion right then...2) points directly
toward the center of the circle you are rotating around. Yes, at any instant there is such a
circle, and this is how physicists and engineers think of cornering accelerations/forces.
(Force is just F = ma, where m = mass of the object, and a = the acceleration. So you see why F
and a are talking about the variables, and m is just constant, so it doesn't change as you ride.
Much.)
So there are two parts to the acceleration here, a(1) that changes speed, and wears out the
center of the tire mostly...and a(2) that changes direction, and wears out the sides of the tires.
SOOOOO...Acceleration (2) is just about cornering, and is calculated: a(2) = v*v/R.
a(2) = velocity squared divided by the radius of that circle.
Velocity, by itself does not matter much. The radius of the circle matter just as much.
MOB, distance differential chart was interesting...but distance only matters if the a(2) values are
the same through all corners. NOT SO, I think. That is much harder to quantify with a chart.
Pavement surface matters a lot too.
I have no answers to the crown thing, only questions...but 30 DEGREES is more crown than I have
ever seen.
saxman
