Relative merits of 60s race bikes

lcrken said:

Not so, Danno. The relaltionship is a direct proportion, as rob ss said. By definition, horsepower equals torque (in pound-ft) times rpm divided by 5252. That's why they are equal at 5252 rpm. In other units the constant will be different, but the linear relationship is the same. You can't have a situation as rpm increases where horsepower is decreasing while torque is increasing. When you hit the point in rpm where horsepower has peaked and started to drop, torque must also be decreasing.

Ken

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If that's true, all torque curves would follow the horsepower curve at exactly the same distance. Horsepower tends to rise steeply, equalling and then surpassing the torque curve at 5252. Are you saying the torque curve cannot continue to rise as the horsepower curve begins to flatten out? I'm not talking about redline or just before when power falls off the table, I'm talking about the slope of the horsepower curve as opposed to the slope of the torque curve. Possibly that was not clear. I guess I should have said rate of increase instead of increase.

Usually the torque curve rises to a peak with the revs, then falls off while the power curve continues to rise. The difference between the two is that a head wind has more effect on a motor which depends on revs to make it's power. The gearing is usually different, so the differences in performance are largely negated. A torquey motor pulling a very high gear is just as likely to get blown backwards as a powerful high revving motor pulling a lower gear. I wonder how many guys change gear long after peak torque has been reached and their bike's acceleration rate has decreased ?