[Monkey Wrench]

when there is some mismatch in gear speeds, the synchro rings help the mating gears to start turning the same speed as each other so that as the gears move into mesh they slide in, otherwise it would be harder to change gears without them, some old cars were built without synchromesh..

the point I am trying to make here is that there are two ways for the gears to be mismatched, gear A is going faster than gear B or, gear B is going faster than gear A.

so lets say the problem is that they shnchro rings are worn so the transmission becomes a little harder to shift.. you may find that changing the style slightly helps..

I believe that the syncros wear in two ways and it is likely common that one side wears out first..

when you doubleclutch and gear down you may note that when you let the clutch off you can control it a little , in one instance you may make it so that when you release the clutch the car lurches akead slightly, the other way you may find the car slows when you let the clutch up. even though both instances are downshifting into the same gear..

if the gears are perfectly matched in speeds, you would notice no surge ahead and no braking action as they are matched.

by getting used to the feel of it, you can control the two different situations..

since one side of the synchro is worn and the other is not then you may find that adjusting this technique favors the side of the synchro that is less worn , resulting in a smoother shift, despite the fact the syncromesh ring has some wear..

by not stressing the synchro and driving it for more miles what can happen is you then wear the synchro back in and thus improve shifting , you are basically reshaping the point on the synchro and smoothing it out.. that's a way to fix it without taking things all apart.

what it requires is some attention to the habit and learning how to shift smoothly every time,, as soon as you are grinding gears or feeling them clunk you are damaging the synchro ring..

each gear has a ring first and second may be the most susceptible.

Ive had old cars that were hard to get into first from a standstill , so Id sort of slip it in when the car is still rolling before I came to a full stop.

often in my old volvo I will doubleclutch down as I approach a light , in that case Im doubleclutching and using the engine as a brake , Ill still apply brakes but I'm taking some stress off the brakes..

often when you hear very experienced riders on Harley Davidson's, you can hear them doing this very well.. usually when approaching a light..

sure they use their brakes but thy also use the transmission and compression to slow themselves and to do that they doubleclutch.. These guys are basically in tune with their machines.. they dont want to wreck them, they really care about them..

also as they are coming to a stop, if they are in first already , then before stopping , but rolling at near waling speed, the light goes green,, then they can simply dump the clutch and take off in first
Since they are already put the bike in the correct gear for their speed.. they have prepared for the event.. they dont need to put their foot down on the pavement or stop the bike completely..

I think its an example of the fact that you dont need to know how a car works to drive one, but if you do it helps you unserstand the physics. after a million instances of almost the same action with only slight variations in habits,, you become more in tune with it all.. like riding a bicycle its a learned habit that once you get it down, you dont really loose it..

if the OP can doubleclutch on a bike then he already has learned it, he just has to get the to get the habits fine tuned then they will be easier to control and make them work to his advantage.

a car has two distinct actions, the wheels are slowing the car, it is decellerating , or the wheels are driving the car, he is accellerating..

every part in the driveline, transmission shaft splines U joints or CV joints , the gears in the tranny the load on all those bearings, the rear axle gears driveshaft splines , the axle shafts may be keyed to brake drums,, etc.. every point along the drive train is constantly changing between the two states..

if you lift a wheel up and the car doesn't have LSD then you can simply turn the back wheel either way with the engine in first and not running..

now you can note quite considerable play,, every little place where there is freeplay all through the driveline is added together so its a good way to tell easily how worn the drivetrain is..

if you have someone turn the wheel back and forth like that, for you. you can go put your hand on things like CV or U joints and feel the movement, to isolate and detect worn parts.

with older worn out cars, they can develop a lot of slop , the result is driving along at 10 MPH and feeling the car surge ahead and back in a jerky motion because they are in a state of limbo and that freeplay keeps reversing.. once driving, acellerating or decellerating constantly , it goes away.. this can make it uncomofrtable to drive a worn car in heavy traffic.
the harder you beat on it, the faster it wears and it involves a whole lot of parts.

I think if you are shopping for a particular car you could do that and take note, the car with less freeplay is the one you want, because fixing that is very expensive , it is involving stacked freplay through the entire drivetrain.

a driver who abuses his machine can wear it out in less miles. If the driver drove like grandma, then that's the one you want..
the kid that went hot rodding in his mom's car.. visually , by looking at the car, hard to tell.. you can drive slowly , put it in that limbo state, take note of how it feels,, a tight car is nicer to drive.

if Im shopping Id avoid a car with a boom box stereo, its a sign.. someone younger owned it and we all tend to wreck out first cars more as we are then young and a bit more rough on things..

Ive noticed that when handing antiques I can note the nature of people, say I handed someone an antique violin, said no more , just observed..

well some will carry it and place it back down carefully in a safe place, they will treat the thing like a baby.. others will put it down more roughly,, its just a difference in human nature. same with drivers.