Shifting without the clutch

[SAV912]

Originally Posted by ddongbap

Anyone else know why clutchless shifting is bad for syncros?

It was just explained to you above. Synchromesh is there to help ease the transition between gear changes. The gears in the half of the transmission that can freely rotate are the ones that come into factor when you rev match and the shift lever freely slides into place. Those gears of the transmission can be freely rotating, or locked to the shaft. The synchros ensure that the speeds of the two shafts/gears are matched perfectly before letting the gears engage.

When you rev match, you are doing the work of the synchros by yourself but still putting excess force on the synchros, but if you mis-rev even slightly and still attempt to shove the shifter into gear and get an awful grinding noise, you are putting wear on not only the synchros, but the gears themselves as well. Sooner or later, you'll start wearing teeth off the gear itself, and eventually, whether or not you rev match perfectly, you will grenade that gear in the transmission. And other gears in the transmission don't like it when there is bits of broken gear roaming freely.

By all means, if you think you can rev match perfectly each and EVERY single time, go nuts. It's not my synchros you're eventually going to destroy. It's yours. So if giving your left leg an exercise during a drive is not worth it to you, then best of luck footing that new transmission bill. You probably should've invested the extra money in an automatic Yaris anyway, if that's the case.

-SAV

[ddongbap]

Originally Posted by SAV912

It was just explained to you above. Synchromesh is there to help ease the transition between gear changes. The gears in the half of the transmission that can freely rotate are the ones that come into factor when you rev match and the shift lever freely slides into place. Those gears of the transmission can be freely rotating, or locked to the shaft. The synchros ensure that the speeds of the two shafts/gears are matched perfectly before letting the gears engage.

When you rev match, you are doing the work of the synchros by yourself but still putting excess force on the synchros, but if you mis-rev even slightly and still attempt to shove the shifter into gear and get an awful grinding noise, you are putting wear on not only the synchros, but the gears themselves as well. Sooner or later, you'll start wearing teeth off the gear itself, and eventually, whether or not you rev match perfectly, you will grenade that gear in the transmission. And other gears in the transmission don't like it when there is bits of broken gear roaming freely.

By all means, if you think you can rev match perfectly each and EVERY single time, go nuts. It's not my synchros you're eventually going to destroy. It's yours. So if giving your left leg an exercise during a drive is not worth it to you, then best of luck footing that new transmission bill. You probably should've invested the extra money in an automatic Yaris anyway, if that's the case.

-SAV

Ok, so say I'm at 60 mph. I know that third gear falls around 4kish rpm. If I revved to 5, and pushed the gear into third and waited for the revs to drop till 4. Then thrid gear would take it. Is that still bad?

I understand how that'll be bad for the gears it self, but wouldn't that take the work off of the syncros?

Btw, idk what the other guys problem was. I just wanted an answer like this.

[SAV912]

Originally Posted by ddongbap

Ok, so say I'm at 60 mph. I know that third gear falls around 4kish rpm. If I revved to 5, and pushed the gear into third and waited for the revs to drop till 4. Then thrid gear would take it. Is that still bad?

I understand how that'll be bad for the gears it self, but wouldn't that take the work off of the syncros?

Btw, idk what the other guys problem was. I just wanted an answer like this.

If you rev'd to 5K and tried shoving it into gear (because it wouldn't just slot right in), it wouldn't go in unless you forced it. If you succeed in forcing it, that's where the wear on your synchros and gear grinding comes in. Hence why the people above mentioned why you have to be absolutely spot on with your rev-matching.

Now if you know that 60 mph is about 4K in 3rd gear (I wouldn't know for sure, my Yaris doesn't have a tach) and held the car at exactly this engine speed in neutral with the gas pedal, then yes. The gear lever should slot right into 3rd gear with no problem. This action of being correct is not really a problem. It's much easier to upshift without the clutch than it is to downshift. It's the fact that every single human being will eventually blip the throttle wrong, mis-shift and force it in, causing excess wear on the synchros since the gear speed and output shaft speed are not correctly matched. Forcing it all the way in will just get gears grinding, just as what happens when missing a shift like we all did once upon a time when we were noob stickshift drivers.

Bottom line, you can try it and you can even become good at it. But that doesn't change the fact that our cars come with clutch pedals for a reason.

-SAV

[ddongbap]

Originally Posted by SAV912

If you rev'd to 5K and tried shoving it into gear (because it wouldn't just slot right in), it wouldn't go in unless you forced it. If you succeed in forcing it, that's where the wear on your synchros and gear grinding comes in. Hence why the people above mentioned why you have to be absolutely spot on with your rev-matching.

Now if you know that 60 mph is about 4K in 3rd gear (I wouldn't know for sure, my Yaris doesn't have a tach) and held the car at exactly this engine speed in neutral with the gas pedal, then yes. The gear lever should slot right into 3rd gear with no problem. This action of being correct is not really a problem. It's much easier to upshift without the clutch than it is to downshift. It's the fact that every single human being will eventually blip the throttle wrong, mis-shift and force it in, causing excess wear on the synchros since the gear speed and output shaft speed are not correctly matched. Forcing it all the way in will just get gears grinding, just as what happens when missing a shift like we all did once upon a time when we were noob stickshift drivers.

Bottom line, you can try it and you can even become good at it. But that doesn't change the fact that our cars come with clutch pedals for a reason.

-SAV

Well, some cars come with other crap nobody ever use sometimes.

Sorry of my questions seem like I'm trying to prove you wrong. I'm just trying to figure it out.

Btw, the gear accepts the shifter because its the right RPM range. Theres no grinding as it goes it. It just goes POP and takes it in. And only at the right RPM range, consistently.

Now, you may be right, but I think its kinda hard to mis shift w/o the clutch, seeing as the gates won't open if you're at the wrong speed range.

Anyways, long story short. Syncros are used to match difference in speeds on the clutch and the different gears. But if you go clutch-less, and use the engine to act as syncros, how would that put wear on the syncros?

[Yaris Hilton]

Originally Posted by ddongbap

But if you go clutch-less, and use the engine to act as syncros, how would that put wear on the syncros?

Because you're not going to perfectly match the speed, and the synchro has a bigger job matching the transmission input shaft plus the massive flywheel and rotating assembly of the engine than just the free floating input shaft and friction disc of the disengaged clutch.

But if you think you can do it better without the clutch than with it, go ahead, wear it out. Don't come back here later complaining about Toyota's low quality transmission that tore up.

[ddongbap]

Originally Posted by Yaris Hilton

Because you're not going to perfectly match the speed, and the synchro has a bigger job matching the transmission input shaft plus the massive flywheel and rotating assembly of the engine than just the free floating input shaft and friction disc of the disengaged clutch.

But if you think you can do it better without the clutch than with it, go ahead, wear it out. Don't come back here later complaining about Toyota's low quality transmission that tore up.

Shiet.... that makes total sense. Thats all I needed to know. Don't get all mad at me.

[Yaris Hilton]

I'm not mad at you.

[SAV912]

Originally Posted by ddongbap

Btw, the gear accepts the shifter because its the right RPM range. Theres no grinding as it goes it. It just goes POP and takes it in. And only at the right RPM range, consistently.

That 'pop' right there is wear on the synchros. If you do it EXACTLY correct, it slides right in with no noise whatsoever. The 'popping' noise is the synchros acting against the force of the shifter sliding into place without the use of the clutch pedal and this action is what wears them out. Sooner or later, you'll get grinds when shifting even when you do use the clutch pedal. Think Honda's 6-speed manual problems in the Acura RSX and Honda Civic Si. I'm not a fan of my shit popping out of gear under normal usage/acceleration, so that's why I'm not a fan of constant clutchless shifting.

-SAV

[ddongbap]

Originally Posted by SAV912

That 'pop' right there is wear on the synchros. If you do it EXACTLY correct, it slides right in with no noise whatsoever. The 'popping' noise is the synchros acting against the force of the shifter sliding into place without the use of the clutch pedal and this action is what wears them out. Sooner or later, you'll get grinds when shifting even when you do use the clutch pedal. Think Honda's 6-speed manual problems in the Acura RSX and Honda Civic Si. I'm not a fan of my shit popping out of gear under normal usage/acceleration, so that's why I'm not a fan of constant clutchless shifting.

-SAV

Oh, I didn't mean it went POP. I meant as in, it just pops in there.