Stick shift drivers: Come in, I have a question!!

[Rix]

I rev match all my down shifts in the corolla, unless I'm trying to upset the car, (sideways fun) then I'll sometimes be on rev limit, or nearly idle into a lower gear.
The truck I rev match downshifts, but there's no upsetting that thing.
Sometimes I just decel, and shift without the clutch.
Sometimes upshift without it too.

 

[rg200amp]

Glad to see im not the odd one out!!!

 

[maersk]

Downshifting does have its downsides. In vehicles not fitted with ABS, for example.

 

[ltslimjim]

Originally Posted By: maersk
Downshifting does have its downsides. In vehicles not fitted with ABS, for example.


Engine braking by downshifting will allowing DFCO for most vehicles, so unless you are jumping from 5th gear at 50 straight into 2nd or 3rd all of the time, going from 5th through each gear down to even 2nd until a complete stop or continuation at a lower speed, you can save fuel that way and help your brakes. If your engine suffers as a result of this, you've got other problems(motor mount etc).

 

[rpn453]

Stop and go: I leave it in gear until stopped, disengaging the clutch at about 900 rpm. Once stopped, I go to first and head off. It slips into first most easily when the transmission is at a complete stop, so I figure that means less wear.

Stop and wait: I leave it in gear until about 900 rpm, where I slip it out without using the clutch. This requires the least effort and I figure it also saves some clutch assembly wear. My fingertips tell me that it doesn't wear the dog teeth any more than doing it with the clutch disengaged. During hard braking or when the engine is cold and trying to rev a little higher, I do use the clutch.

I never use neutral while in motion. If I'm coasting, I figure I might as well use the momentum to drive the engine and power the accessories.

I only downshift while slowing if I'm preparing to accelerate again.

 

[maersk]

Originally Posted By: ltslimjim
Originally Posted By: maersk
Downshifting does have its downsides. In vehicles not fitted with ABS, for example.


Engine braking by downshifting will allowing DFCO for most vehicles, so unless you are jumping from 5th gear at 50 straight into 2nd or 3rd all of the time, going from 5th through each gear down to even 2nd until a complete stop or continuation at a lower speed, you can save fuel that way and help your brakes. If your engine suffers as a result of this, you've got other problems(motor mount etc).


What I meant is one of your driven wheels can lock up if downshifting under braking to go round or accelerate out of a corner, at least on a FWD car like mine.

This will instantly halve the transmission's output shaft's speed ruining the engagement and possibly resulting in damage or undue wear.

It has happened to me a number of times and it certainly sounds awful if either wheel locks under braking by chance over a patch of ice or a puddle.

 

[Craig in Canada]

Originally Posted By: maersk


What I meant is one of your driven wheels can lock up if downshifting under braking to go round or accelerate out of a corner, at least on a FWD car like mine.

This will instantly halve the transmission's output shaft's speed ruining the engagement and possibly resulting in damage or undue wear.

It has happened to me a number of times and it certainly sounds awful if either wheel locks under braking by chance over a patch of ice or a puddle.


This is the whole reason for rev-matching, which has been mentioned by most posters in this thread. Even if you aren't rev-matching you shouldn't be popping the clutch on a downshift. There is no "instant" anything - it's all up to you as the driver.

Frankly, having an automatic transmission that decides to do whatever it wants, whenever it wants is MORE dangerous if conditions are as ultra-slippery as you describe.

If you're locking a wheel due to downshifting a FWD car in a "puddle", you need much better tires or to seriously work on your standard transmission driving techniques.

 

[maersk]

Originally Posted By: Craig in Canada
This is the whole reason for rev-matching, which has been mentioned by most posters in this thread. Even if you aren't rev-matching you shouldn't be popping the clutch on a downshift. There is no "instant" anything - it's all up to you as the driver.


Rev-matching has nothing to do with it. What happens is one wheel might lock up on a patch of ice or puddle as you are applying the foot brake concomitant with you engaging the lower gear.

As one wheel locks up while the other one doesn't, not having passed over ice or water, the output shaft from the pairs of pinions in the gearbox to the differential built into the gearbox halves its speed as dictated by the diff ((0 RPM + still spinning wheel RPM) / 2).

Obviously this makes it impossible to complete engagement because the input shaft and clutch disk have considerable momentum and are now suddenly spinning at twice the rpm they should in relation to the output shaft for the given gear you were just about to engage and the synchro grinds. Badly.

I've had this happen to me a number of times, it is not conjecture. I shudder at the memory.

Originally Posted By: Craig in Canada
Frankly, having an automatic transmission that decides to do whatever it wants, whenever it wants is MORE dangerous if conditions are as ultra-slippery as you describe.


Yes but at least it will never grind.

Originally Posted By: Craig in Canada
If you're locking a wheel due to downshifting a FWD car in a "puddle", you need much better tires or to seriously work on your standard transmission driving techniques.


The lock-up does not occur because of anything the transmission does but because of the service brakes. You can't lock a wheel up with just the inertia of the clutch disk and gearbox input shaft.

Better tires, that I do. I have a pair of cheap-[censored] turkish Lassa Impetus 2s on the front.

Yes, I skimp on tires.

 

[Rix]

In the corolla (rear drive), it just helps the car rotate

Coming into a corner hot in 3rd, hard on the brakes, let off the gas pedal, cram it in second, drop the clutch, countersteer, floor it.
GREAT FUN.

 

[subiedriver]

I'm a downshifter, down to second, never into first. I've got 60K miles on my pads and they are still at 6mm, 50%. My clutch is just fine at 115,000 miles. I don't think its going to be an issue, its become a habit for me.

 

[rpn453]

Originally Posted By: maersk
Rev-matching has nothing to do with it. What happens is one wheel might lock up on a patch of ice or puddle as you are applying the foot brake concomitant with you engaging the lower gear.

As one wheel locks up while the other one doesn't, not having passed over ice or water, the output shaft from the pairs of pinions in the gearbox to the differential built into the gearbox halves its speed as dictated by the diff ((0 RPM + still spinning wheel RPM) / 2).

Obviously this makes it impossible to complete engagement because the input shaft and clutch disk have considerable momentum and are now suddenly spinning at twice the rpm they should in relation to the output shaft for the given gear you were just about to engage and the synchro grinds. Badly.

I've had this happen to me a number of times, it is not conjecture. I shudder at the memory.

I see. I also initially didn't understand what you were getting at.

You could always double clutch. It's effortless once you get used to it. I always double clutch any rev-matched downshifts - even heel-toe - and I rev-match any downshift over about 1500 rpm. I rarely heel-toe on the street though, because I find it difficult to hold braking force steady while blipping during the sort of light braking that street driving requires. Instead, I downshift right before braking when approaching a turn. After blipping the throttle to rev match, I immediately go to the brake, so I begin braking right as I'm engaging the clutch again.

 

[xxch4osxx]

Originally Posted By: hate2work

Brakes are for slowing/stopping, not gears.
Thats ok for cars, but try that in a big truck.

 

[Maritime Storm]

Agreed. I'm the son of a 40 years on the road trucker, coasting in neutral is cardinal sin as far as my father has taught and is illegal in a lot of areas. Your vehicle should always be in the right gear for the speed it is moving in case you accelerate to avoid and accident.

 

[mechtech2]

So a diesel truck accelerates so well that it needs to be in gear one half second sooner?
The lighting like acceleration is that dependent on being in the proper gear?

 

[xxch4osxx]

Originally Posted By: mechtech2
So a diesel truck accelerates so well that it needs to be in gear one half second sooner?
The lighting like acceleration is that dependent on being in the proper gear?
Its about control.

 

[Maritime Storm]

Not many vehicles accelerate in neutral, in a panic it is much faster to mash the throttle pedal then to try and figure out which gear to be in then mash the throttle.

 

[123Saab]

I love stickshifts, Unfortunately I had ankle surgery twice in the last 10 years and suffer from chronic pain (work accident) so my 1985 Saab SPG Turbo basically just sits in the garage......

 

[maersk]

Originally Posted By: Maritime Storm
Not many vehicles accelerate in neutral, in a panic it is much faster to mash the throttle pedal then to try and figure out which gear to be in then mash the throttle.


A little bit of torque always makes it to the wheels. Especially on a 'seasoned' transmission. This can be plainly seen if you get the car up on a lift or if you have a driveshaft totalled from a side impact.

The part that's still connect to the differential will spin freely.