Cheapracer- are you sure your corrections are OK? (or are you making a point of a sort- like a jab from some sort of torque vs power argument?) Methinks Gruntguru had phrased it right- when changing gear one adjusts revs to match output torque, and therefore power must 'spike' during gearchange... If power should remain constant, one shzould not change revs during gearshift, and I don't think it's a very wise thing to do.
Gruntguru, OTOH- if spike (or jerk, as I would put it) came only from rotational inertia... that would mean you were saying exactly what Gerrard is saying? The jerk should obviously come from both inertia and unmatched revs (or as is referred to- torque spike)- and the implication is that power is then indeed not transferred during the shift.
You change gear so as to match component RPM.
Transfering torque is a different requirement.
Of course you want to change gear as fast a possible and to transfer torque for as long as possible.
The two things are not the same.
Can grunt explain how it is possible to measure the torque on the baulking components at each gear at the moment of gearshift?
Measuring the output (at the diff or wheel) does not take into account the complex forces within the gearbox at the relevent components.
Let me help.
It is possible to measure the twist (Torque) of the closest input shaft and output shaft to the two gears under shift investigation.
This requires electric contact strips lengthways on the shafts and the sensors measure the linear accuracy of these strips, as this measurement changes with torque applied and how much the shafts twist.
Of course the torque can only be measured if there is a load to apply the force against.
The spike that the marketing boys show, occurs at the central point of the gear shifts where both the gears in question are at their very least engaged state.
and the (so called zero shift or seamless parts) are at their weakest geometry for transfering high torque levels.
So ask yourselves this, 'why is there a so called spike at this point'?
If it were maximum torque from the engine at near Maximum RPM, this would without doubt grenade the geartrain.
No as cheapy corrected it can only be a 'power' spike as a result of rotational inertia.
This being the case, it PROVES, that NO torque can possibly be being transfered from input of the gears to output at the mid point of gearshifting where the spike appears.