[honeybee]

I think we are digressing from the topic of skipping gears here.

My own experiences on skipping gears:

Upshifting: Skipping gears while upshifting has always been deliberate for me. Almost always after I have built up good speed for overtaking in the third gear and after the overtake I find the road is sloping downwards or I have built up enough speed to carry into the fifth gear directly. In each case I only skipped when I felt the revvs were high enough to allow me to skip a gear.

Downshifting: I regularly shift down from fifth to third. I am able to sail in the fifth gear at speeds as low as 40kmph (even with five people on board), so whenever I need to stop, I let off the accelerator and cruise along (using the engine braking) till the car slows down to around 40kmph and then downshift to 3rd, still letting off the accelerator, which allows me to come to a halt without much use of breaks. I also downshift from fifth to third whenever I need to stop suddenly. A few times when making sudden halts I have braked hard while in fifth gear (from speeds of 100kmph or thereabouts) and after the car has slowed down to about 55kmph, shift into third and then use the engine braking as well as the foot brakes to halt the car within a safe distance.

Can someone explain mechanically if there are any pros and cons of skipping gears while downshifting?

Here's some interesting info I found, though I don't necessarily agree with anything/everything said there:
Driving a Manual Transmission , thread @

[McLaren Rulez]

Don't racing drivers who have regular gearboxes (not flappy paddles) always skip gears while downshifting? That is, they slow down to whatever speed the corner is to be taken at and drop to the appropriate gear and accelerate out.

[narendra.vw]

In my opinion , don’t slip while up shifting or down shifting. If needed, stay in the next gear less then it is necessary, then change. This keeps gear box shifter links in good condition. All connected parts including engine, clutch life affects by slipping gears. Torque plays major part.
I believe, rally drivers don’t slip gears. If they do, rpm of the engine may suddenly increase or decrease, this leads to engine brake down. Rally cars have short gearing.
don’t compare normal car to rally car.
My experience: Make sure up hill or down hill always be in lower gears. Over taking, or slippery condition never be in 5th gear.

[adisag]

In most driving conditions, you need/want to get to a reasonable cruising speed (say 40-50 Km/h) with quick acceleration, once this speed is achieved, it is desirable to drive at the engine RPM which would be most fuel efficient at that speed (even if further acceleration is slow). So typically I accelerate till 50 Km/h in 3d taking the revs till the engines sweet spot, and then shift directly to 5th, so engine RPM's drop to a minimum (making sure the engine does'nt lug). Similarly in slower traffic (or maybe a more powerful car) you could probably shift straight from 2nd to 4th - But make sure you're familiar with your engines powerbands and gearing so that you don't end up shifting gears at the wrong RPM.

Originally Posted by honeybee

I think we are digressing from the topic of skipping gears here.

Downshifting: I regularly shift down from fifth to third. I am able to sail in the fifth gear at speeds as low as 40kmph (even with five people on board), so whenever I need to stop, I let off the accelerator and cruise along (using the engine braking) till the car slows down to around 40kmph and then downshift to 3rd, still letting off the accelerator, which allows me to come to a halt without much use of breaks.

I Agree 100%

IMHO - there should be absolutely no harm done by skipping gears as long as you are familiar enough with the car to ensure the car does'nt lug (at low RPM's) or generate excessive engine-braking (at high RPM when downshifting)

[aargee]

Originally Posted by SirAlec

what if you have a car that has a weak handbrake.??

You can definitely skip gears, many times i have gone 2nd to fourth. fourth to 2nd. 1st to third with ease. i never skip a gear to go to overdrive though.

Sir, if the car has a weak handbrake, then I wouldn't even park the car on the slopes right? Ok, lets assume I used gears to park the car on the slope, in that case I would use brakes & half clutch in such a way that the car stands still but does not shut off the engine. On diesel cars its quite easy to have half clutch & remove the foot completely off the gas pedal, while in petrol cars, its little tricky, but can be done with little practice.

Once the car stands still without the engine shutting off, shift the leg from brakes to gas pedal, accelerate & release the clutch.

Originally Posted by SirAlec

You can definitely skip gears, many times i have gone 2nd to fourth. fourth to 2nd. 1st to third with ease.

I got your above point on, but couldn't understand the below

i never skip a gear to go to overdrive though

I too do 5-3, 3-1 depending upon the speed of the vehicle; 1-3 or 3-5 I do only after difficult successful overtakes.

Manufacturers would have given 3 gears itself :

Nope; its not a bad until you've revved the engine sufficient to avoid knocking. If there were only 3 gears, people had to rev the engine lot before each shift that affects FE. Its bad only when someone has the habit of driving with skipping gears.

[SirAlec]

Originally Posted by aargee

Sir, if the car has a weak handbrake, then I wouldn't even park the car on the slopes right?

Thats funny! do you think all the cars that runs on hills have proper handbrakes. They use wood stopper or plain stones.

Originally Posted by aargee

I got your above point on, but couldn't understand the below

Meaning I never go from third to 5th.

[GTO]

I see absolutely no problem with skipping gears, as long as:

a) You don't shift too low & over-revv the engine (e.g. engage 2nd gear at 100 kph).

b) You don't shift too high & "lug" the engine (e.g. 5th gear at 30 kph).

We really won't have a chance to skip gears within the city, as we would on the highway.

[karty_83]

Say we are in the 4th gear and we slow down to a speed of 20. Which approach consumes more fuel ?

(1) Downshift to 2nd and proceed up shifting to 3rd and 4th.
(2) Continue accelerating in the 4th.

[clevermax]

Originally Posted by karty_83

Say we are in the 4th gear and we slow down to a speed of 20. Which approach consumes more fuel ?

(1) Downshift to 2nd and proceed up shifting to 3rd and 4th.
(2) Continue accelerating in the 4th.

Whether it consumes more fuel or not, I won't continue accelerating in 4th from a speed of 20Kmph. It lugs the engine, it is so boring thing to do because it will take ages to accelerate. I lot of newbie drivers lug their engines so happily, as if downshifting is not in their modus operandi at all! Sometimes you can hear the metallic sound coming from those poor engines when they are driven in 4th or 5th gear at speeds like 20!

To answer the question, yes it may consume more fuel when you floor the gas pedal in 4th gear to accelerate, than downshifting to 3rd or may be second and smoothly accelerate. I recently tried this, I had the IC mode on my Punto's DIS, and noticed the IC while engine was lugged in 4th gear to accelerate, and then again, in 3rd gear with moderate press on the accelerator. Instantaneous Consumption was like 9 or 10 Kmpl when I floored the gas pedal in 4th, and it was like 13 -14 when the car was accelerated from the same speed in 3rd gear.

[aargee]

Originally Posted by karty_83

Say we are in the 4th gear and we slow down to a speed of 20. Which approach consumes more fuel ?

(1) Downshift to 2nd and proceed up shifting to 3rd and 4th.
(2) Continue accelerating in the 4th.

Well to answer your point, it depends on the RPM. 4th & 20, I'd assume the RPM should be around 1-1.5K. If you want to accelerate, well, this is very much likely to cause engine to knock, I would definitely shift down & bring the RPM to appropriate level.

Meaning I never go from third to 5th

Well if one drives well, it never requires to skip a gear, this is what my experience has taught. Let me explain

Lets say we do 4th gear & 40 Kmph & are in the mode to accelerate to 60 & 5th gear. Now we see a hinderance for my acceleration (if one is cautious driver, they see the blocks well in advance; if its emergency, well that's a different story all together) and put off the gas pedal & prepare to brake while still in 4th gear, now the speed comes down to say 30, now shift down to 3 & on further speed coming down, shift to 2nd & this is the best way to go about. See I didn't skip a gear at the same time I brought down the gear appropriately to the speed & RPM.

But if I need to do a medium to difficult overtakes, yes, I don't see any harm in skipping gears without which I will land up in mess.

Thats funny! do you think all the cars that runs on hills have proper handbrakes. They use wood stopper or plain stones

One moment, what I meant here is using the hand brakes. To rephrase, "Sir, if the car has a weak handbrake, then I wouldn't even park the car on the slopes using handbrakes" right.

[clevermax]

Originally Posted by aargee

I got your above point on, but couldn't understand the below

i never skip a gear to go to overdrive though

Originally Posted by SirAlec

Meaning I never go from third to 5th.

well in some cars even the 4th is overdrive, so probably you can refine the statement as the clarification given itself, that you never go from 3rd to 5th.

[SirAlec]

One moment, what I meant here is using the hand brakes. To rephrase, "Sir, if the car has a weak handbrake, then I wouldn't even park the car on the slopes using handbrakes" right.

, what if the whole city is based on hills.

that is my personal experience (using a 5 speeder swift) and hence was stated in that context.
Point being not to go to overdrive directly even if the rpm looks seemingly good to go.

[clevermax]

Originally Posted by SirAlec

, what if the whole city is based on hills.

that is my personal experience (using a 5 speeder swift) and hence was stated in that context.
Point being not to go to overdrive directly even if the rpm looks seemingly good to go.

Understood. If the engine is happy revving, and if you are in 3rd and tacho reads something like 5500, (Petrol) going straight to 5th won't hurt. On the other hand, shifting from 3rd at that point where you'd normally shift to 4th (around 3K rpm) is not good.

[RajaTaurus]

Gear skipping comes kind of naturally and sponteaneously, if you have been driving the same car for reasonably good period.
Example: You are overtaking in 3rd gear and you need to clear the vehicle in front and get back to your lane safe, so use both hands on the steering wheel. And your revs are showing more than ~4000. Once you are on your lane, you speed is good 80-90, with 3rd gear still engaged, so if the road is clear, skip the 4th gear and go to 5th.
In Camry I very often went from 3rd to 5th even on a straight road. That car has one hell of a gear-box.

[aargee]

Originally Posted by SirAlec

, what if the whole city is based on hills.

that is my personal experience (using a 5 speeder swift) and hence was stated in that context.
Point being not to go to overdrive directly even if the rpm looks seemingly good to go.

Yes, you're right; experienced this in Thirupathi & Madikeri hills. Anyway, I couldn't think this in theory; I mean, little difficult for me to put in words, but can understand it when driving.