Short shifter Vs. Height of shifter knob
 

I got my BM shifter working great at 45% reduction, but it takes some effort to make the gears change. I guess that is due to the stick being to short and the knob being short also (using a greddy CW Knob).

my question is, if I add a knob which is tall - taller than a round knob (3"), will I be undoing the so called 45% shift reduction? (it appears my arm/hand would have to travel a little more to engage the gears thus, no really short-shifting) ?

your assumption is correct. the act of shifting is simply mechanical leverage. if you shorten your lever arm (shift lever), it will require more force to shift, but reduce the travel of the end of the arm (your hand). if you lengthen it back a little, you'll reduce the force, but increase the travel. it is a linear relationship. if the BM shifter requires to much force, use the taller knob like you're thinking. maybe you can find something between stock height and BM height which will feel best for you.

I thought the shift gate itself has shorter paths with a short shift kit, while a taller shifter would add leverage and make shifting easier.

Get a heavier counterweighted knob.

well that is what I am trying to find out

no. unless you change the transmission itself, it will still require the same amount of cable throw. thus regardless of what shift lever you use, you still need the cable to move "X" distance. so the gates will remain the same. all that changes is the length of the lever (or in some cases it could be possibly to retain the same length lever, but change ratios elsewhere... eitherway, shorter throw = more force required)

and a taller shifter then just adds leverage?

Not quiet right.

If you change the pivot point, you will change the distance that your hand has to move to move the opposite end of the shift stick the same distance.

isn't that exactly what i said?

look this is so easy people:

long shift lever = easy shifting = long throw

short shift lever = more force in shifting = shorter throw

The farther your hand is away from the pivot point (vertically), the farther your hand will travel to make the same shift (horizontally).

Setup 1: Long knob (+3in), Stock shifter
Setup 2: Short knob, Short shifter (-45*)
Setup 3: Long knob(+3in), Short shifter (-45*)
Setup 4: Short knob, Stock Shifter

S1 has the longest throw (least effort)
S2 has the shortest throw (most effort)
(obviously)

Comparing S3 & S4 is where your question lies, and it could be hard to say which exactly has the longer throw without equations and some measurements of the different parts of the shifter. For example you would have to know the length of the shifter above the pivot point and the % increase in length after the longer shift knob was added...among other things. If I had to guess though, I would say that S3 (Long knob, short shifter) will have a shorter throw than S4 (Short knob, stock shifter). As far as effort goes, you may find it too hard or too soft even after the change in shift knob; and no one can decide what feels best but you.

It's not the just the shifter height, it's whether the proprotional distance between the pivot point, the effort and the load is reduced.

You could have a a shift of exactly the same height above the pivot, that has an increased height below the pivot and your throw will be reduced.

And every possible combination inbetween.

If the proportions of the above and below pivot stay the same, there will be no ease of leverage gained.

It's actually not that easy.

thanks you for all your answers !!