Lets learn to drive manual! Save my clutch Season 1

[himbo]

Originally Posted by flashburn

Mechanically speaking though, why does it matter? Do the synchro's engage as the shifter is gated into a gear? Or as the clutch is depressed?

It can cause extra wear on the synchros if you're moving. Frankly you only need 1st for fast starts and starting uphill. 2nd is short enough to start on. I use a mixture of either 1st or 2nd to start.

[_______]

Originally Posted by Hardy

Can anyone actually heel-toe with the stock gas pedal in this car? I was playing around at lunch, and I think I would have to remove my knee joint to twist enough to do it. Any recommendations to a full length fuel pedal that would fix this?

Some people its fine for them but I think it lacks feel. When I do it sometimes I over rev quite substantially because i really cant feel how much input im putting on the throttle. I ditched heel toe and just brake then quick rev match and back on the brakes. im much more smoother that way but im probably annoying the person behind me going on and off on the brake lights. Might invest on the cusco pedal.

[Suberman]

Originally Posted by flashburn

Mechanically speaking though, why does it matter? Do the synchro's engage as the shifter is gated into a gear? Or as the clutch is depressed?

The clutch has nothing to do with the synchros. The clutch is entirely separate from and outside the gearbox.

When you rest your hand on the gear lever you will partially engage the synchros at some pressure. If you know what you're doing you can feel that pressure and in this gearbox at least you can feel the selector sleeve begin to engage.

The gear selector moves a rod inside the gearbox. On that rod is a fork which engages in a groove in the selector sleeve. That selector sleeve moves the synchronizer assembly away from the already selected gear, or neutral as the case may be, and towards the gearset to be engaged. As the selector sleeve moves towards that new ratio the synchronizer cones contact each other. As they do so the friction so generated matches the speeds of the inner and outer synchro cones. On first and second there are three concentric cones. On the remaining gears only two are needed.

Inside the cones are grooves with small blocks of metal in them. These are baulks preventing the selector dogs from engaging prematurely. Only when the two sets of cones are turning at almost exactly the same speed do the baulks move out of the way and the dog teeth on the synchro cones mesh with the dog teeth on the gearset and the selector slides home.

The gears don't move and you don't change gears, you engage the dogs.

If you do all this too slowly the dogs will clash. You need to shift firmly and quickly to ensure the synchro cones are pressed together with high force.

You should not rest your hand on the gear lever between shifts unless you know what's going on. Once you apply any pressure to the gear lever you may begin to load up the shifter fork which may load up the selector sleeve causing unnecessary wear. Once you know exactly what's happening when resting your hand on the gear lever then you will know not to apply any pressure until you're going to shift. Then it doesn't really matter. I was taught not to rest my hand on the gear selector between shifts and that's definitely the preferred technique. Of course, if your doing a zero to 60 you can keep your hand on the gear lever between shifts because you need to, even in a car this slow!

It is very important not to shift too slowly, synchros work best when you really pressure them.

[Gords_zenith]

Originally Posted by Suberman

The clutch has nothing to do with the synchros. The clutch is entirely separate from and outside the gearbox.

When you rest your hand on the gear lever you will partially engage the synchros at some pressure. If you know what you're doing you can feel that pressure and in this gearbox at least you can feel the selector sleeve begin to engage.

The gear selector moves a rod inside the gearbox. On that rod is a fork which engages in a groove in the selector sleeve. That selector sleeve moves the synchronizer assembly away from the already selected gear, or neutral as the case may be, and towards the gearset to be engaged. As the selector sleeve moves towards that new ratio the synchronizer cones contact each other. As they do so the friction so generated matches the speeds of the inner and outer synchro cones. On first and second there are three concentric cones. On the remaining gears only two are needed.

Inside the cones are grooves with small blocks of metal in them. These are baulks preventing the selector dogs from engaging prematurely. Only when the two sets of cones are turning at almost exactly the same speed do the baulks move out of the way and the dog teeth on the synchro cones mesh with the dog teeth on the gearset and the selector slides home.

The gears don't move and you don't change gears, you engage the dogs.

If you do all this too slowly the dogs will clash. You need to shift firmly and quickly to ensure the synchro cones are pressed together with high force.

You should not rest your hand on the gear lever between shifts unless you know what's going on. Once you apply any pressure to the gear lever you may begin to load up the shifter fork which may load up the selector sleeve causing unnecessary wear. Once you know exactly what's happening when resting your hand on the gear lever then you will know not to apply any pressure until you're going to shift. Then it doesn't really matter. I was taught not to rest my hand on the gear selector between shifts and that's definitely the preferred technique. Of course, if your doing a zero to 60 you can keep your hand on the gear lever between shifts because you need to, even in a car this slow!

It is very important not to shift too slowly, synchros work best when you really pressure them.

This is a good quality post! I don't know how accurate you are but I like your description - seems logical to me. See, this is what a useful post looks like. And I'm not being sarcastic. Legitimately good.

[qqzj]

Thanks for the description. But w/o a proper graphical help, I doubt a lot of guys will actually benefit from it.

Originally Posted by Suberman

The clutch has nothing to do with the synchros. The clutch is entirely separate from and outside the gearbox.

When you rest your hand on the gear lever you will partially engage the synchros at some pressure. If you know what you're doing you can feel that pressure and in this gearbox at least you can feel the selector sleeve begin to engage.

The gear selector moves a rod inside the gearbox. On that rod is a fork which engages in a groove in the selector sleeve. That selector sleeve moves the synchronizer assembly away from the already selected gear, or neutral as the case may be, and towards the gearset to be engaged. As the selector sleeve moves towards that new ratio the synchronizer cones contact each other. As they do so the friction so generated matches the speeds of the inner and outer synchro cones. On first and second there are three concentric cones. On the remaining gears only two are needed.

Inside the cones are grooves with small blocks of metal in them. These are baulks preventing the selector dogs from engaging prematurely. Only when the two sets of cones are turning at almost exactly the same speed do the baulks move out of the way and the dog teeth on the synchro cones mesh with the dog teeth on the gearset and the selector slides home.

The gears don't move and you don't change gears, you engage the dogs.

If you do all this too slowly the dogs will clash. You need to shift firmly and quickly to ensure the synchro cones are pressed together with high force.

You should not rest your hand on the gear lever between shifts unless you know what's going on. Once you apply any pressure to the gear lever you may begin to load up the shifter fork which may load up the selector sleeve causing unnecessary wear. Once you know exactly what's happening when resting your hand on the gear lever then you will know not to apply any pressure until you're going to shift. Then it doesn't really matter. I was taught not to rest my hand on the gear selector between shifts and that's definitely the preferred technique. Of course, if your doing a zero to 60 you can keep your hand on the gear lever between shifts because you need to, even in a car this slow!

It is very important not to shift too slowly, synchros work best when you really pressure them.

[SoCal909]

Originally Posted by Hardy

Can anyone actually heel-toe with the stock gas pedal in this car? I was playing around at lunch, and I think I would have to remove my knee joint to twist enough to do it. Any recommendations to a full length fuel pedal that would fix this?

Yeah I was going to see if I could practice heel-toeing (I am new to manual trans) since I am now pretty good at downshifting regularly. But I have size 13 feet and there is no way in hell I can move my foot the right way in order to heel-toe with these stock pedals. Unless I move my foot way up the break pedal which is just weird

[schmearcampain]

Originally Posted by daiheadjai

I couldn't do it at all - I bought the Cusco pedal and it helped immensely.
I am planning to learn and perfect my technique with the Cusco, then maybe remove it before I return the car at the end of my lease and try it on the stockers.

Same here. My guess is all the Unintended Acceleration lawsuits against Toyota forced them to make a tiny gas pedal that's situated really far away from the brake pedal. The Cusco pedal is perfect. It makes the gas pedal wider by a good amount and also raises it (adds thickness). I don't even actually use my heel and toe, I have big feet and can press the brake with the left half of my foot and roll my ankle a bit to blip the throttle with the right half of my foot.

Also, I had no idea about resting my hand on the shift knob being a bad thing. I've been driving a manual for nearly 30 years with my hand on the knob nearly all the time and never knew this. Then again, I've never had a transmission go bad either...

[flashburn]

Originally Posted by Suberman

The clutch has nothing to do with the synchros. The clutch is entirely separate from and outside the gearbox..snip...

Thanks a lot for that explanation! It helped a lot.

[daiheadjai]

Originally Posted by schmearcampain

Same here. My guess is all the Unintended Acceleration lawsuits against Toyota forced them to make a tiny gas pedal that's situated really far away from the brake pedal. The Cusco pedal is perfect. It makes the gas pedal wider by a good amount and also raises it (adds thickness). I don't even actually use my heel and toe, I have big feet and can press the brake with the left half of my foot and roll my ankle a bit to blip the throttle with the right half of my foot.

Also, I had no idea about resting my hand on the shift knob being a bad thing. I've been driving a manual for nearly 30 years with my hand on the knob nearly all the time and never knew this. Then again, I've never had a transmission go bad either...

I've heard similar things from other folks, and it IS a physical connection between driver and gearbox, so it makes sense to me...

On the issue of heel-toe, one possibility is that we're all trying to do this during (relatively) conservative braking that we do on the street.
I experimented last night in an empty industrial area - under hard braking, it seems to become much easier to heel-toe, as your brakes are on full (rather than trying to modulate for a smooth stop like in regular street driving)

[Want.FR-S]

Originally Posted by flashburn

What about shifting into first gear, while coming to a stop (say at a stop sign), but not disengaging the clutch until < 5MPH? Is that still putting wear on the synchros?

The quick answer to your question is: it does not matter on the synchros in your scenario, as Suberman said. A little bit longer explanation is that if you can shift into 1st while moving, the synchro is already locked the input shaft and gear so no wear is done. Whether you disengaging the clutch or not does not affect the wear on synchro, but when you shift into first gear could potentially wear the synchro.

But how is that so? Here is the explanation.

As you may know, the torque generated by the engine is sent through clutch and to the input shaft of the gear box, multiplied by the gear box and the diff to the driving wheel. The car engine sends torque (power) to the flywheel, which is connected to the clutch. Think of the clutch as two sides dish, one side connected to the engine flywheel and the other side to the input shaft of the gear box. When release the clutch padel (fully engaged), two disks connected and the engine torque is transmitted to the input shaft of the gear box. When you press the clutch fully, it disengages the disks and the engine torque is disconnected from the input shaft of the gear box.

The input shaft of the gear box can be connected to different gears based on gear selector. Prior to connecting the input shaft to a gear, the synchro tries to *match* the rotational speeds of input shaft and gears. When the car is stationary, the gear does not rotate. If the car engine is started but the clutch is pressed, the input shaft will slow down to stationary if it was connected to the clutch before. You will have no problem engaging the first gear, or reverse since the input shaft is not connected to the engine so the synchro does its work to slow the input shaft to 0 to match the speed of gear. When you release the clutch, the two disks bite at engagement/friction point, and the torque is transmitted from the engine through clutch/input shaft/gearbox/diff and to the driving wheel.

Now knowing how this works, lets review your scenario here: What about shifting into first gear, while coming to a stop (say at a stop sign), but not disengaging the clutch until < 5MPH? Is that still putting wear on the synchros?

Just before you shift into 1st gear while car is moving, you need to clutch in and thus disengage the engine from input shaft. At this point, the input shaft rotates at the same speed as the gear as they were connected before. Now, when you shift the gear into Neutral, the input shaft disengages from the gear. When you shift the gear into 1st, the input shaft engages to the new gear ratio. Now, the key point here is *how much a difference of rotational speeds at these two incidents?* If you try the extreme case with running at 3K rpm with 4th gear (~42 mph) and trying to shift into 1st gear, the input shaft cannot handle such a great change so the synchro will do triple times to *match* the speeds, and thus this will hurt the synchro. If we look at the gear ratios of 1st and 4th gear of this car, to run in 1st gear to reach ~42 mph, the engine needs to rev to about 9K RPM (which is off the rev limiter). So if you try to do a 4-1 gear change at 3K rpm while at 4th gear, you are forcing the synchro to rev the input shaft from 3K to 9K! And you if release the clutch by mistake, you force the engine to rev to 9K and boom you could blown the engine!!

That is the reason why when you down shift, you should gradually change gears and rev match to reduce the *difference* between clutch and input shaft (to reduce wear on clutch) and *difference* between input shaft and gear (to reduce wear on synchro).

Hopefully this long explanation can help you understand how this works and why.

[schmearcampain]

Originally Posted by daiheadjai

I think if you want to be smooth (at least for the 1-2 and 2-3 shifts), you will need to utilize some mild slip on the clutch... It takes practice but it is doable.

No, you just need to shift slower. The revs have to drop more to match when upshifting between gears with ratios so far apart.

e.g (Hypothetical numbers) if you're shifting from 5th to 6th @ 55 MPH. In 5th gear you're at 3500 RPM. 55 MPH in 6th is 3250 RPM. Shifting gears at a normal speed will allow the engine to slow down just about that amount before you disengage the clutch. Smooth transition.

Shifting from 2nd to 3rd at 35 MPH. In 2rd gear you're at 4000 RPM. 3rd gear at 35 mph is 3000 RPM. Shifting gears at normal speed will NOT allow the engine to slow down a full 1000 RPM, so when you release the clutch it's jerky. Slow down your shifting speed so you release the clutch at 3000 RPM.

[brzr]

Good thread
Although my frs is an auto the other car is a manual

My question is something that I read somewhere
If you are stopped at a stoplight and you keep your car in neutral would that be an automatic fail for a license?
And why would that be?
All I can think of is that you wouldn't be as quick to react in case something comes up vs to having it in 1st already?

[chrisl]

I don't know about license examiners, but you should keep your car in neutral at a light, since holding the clutch in for an extended time puts more wear on the throwout bearing.

[brzr]

Originally Posted by chrisl

I don't know about license examiners, but you should keep your car in neutral at a light, since holding the clutch in for an extended time puts more wear on the throwout bearing.

Right

So I'm trying to figure out why that would be a fail