I was talking to my friend this weekend and wanted to post and ask all the manual drivers out there:

lets say im in 5th gear going 45-60mph...and i see traffic up ahead. i slow down with the brakes to like 30mph...is it wrong to just go from 5th to 3rd?

my friend told me that i am suppose to go 5th to 4th, let the clutch engage at 4th, then downshift to 3rd. the only time you don't have to do this is if you blip the throttle when tranny is in neutral for that split second going from 5th to 3rd.

^from that...if i don't blip the trottle, and just downshift (without over-revving), is it bad for the syncros (as my friend says it would)?

the reason i ask, is because sometimes im lazy to rev match and just want to downshift..and if i am suppose to go down in order, then by the time go through the gears, while depressing on the brakes, i should be in 2nd already.

so what's the correct way?

btw, this is not my first stick car, but i wanted to see what people think about this issue.

 

Whenever I have to slow down, I always heel-and-toe downshift. For your example, I would heel-and-toe from 5th-->4th-->3rd, then brake until I hit around 1500 RPM, then shift into neutral.

 

In the example you can go straight to 3rd, no problem. Even if you blip throttle there's no need to downshift through 5-4-3 - you can go 5-3 directly as long as you know the RPM and speed combination.

 

^ what do you mean as i know the speed?

if i go to 5-3 and rpm was at 2000 then it shoots up to like 3500...is that bad? i usually blip it to match the rpm and speed of the car...so it won't be jerky..but if you dont blip, is that bad?


also, sometimes i get lazy and if im going like 40mph on local, and i see a red light, i put it to neutral and let just let it roll up to the light. but i hear people say that u should press clutch pedal and leave shifter in gear and let it coast that way then switch to neutral when you stop. either way works right?

 

it's mostly preference. Blipping is always good so you put less stress on clutch/everything else

 

doing this puts excessive wear on the throw out bearing. i leave it in gear when i coast just incase i need to make any emergency moves.

 

thank you finally some1 whoknows it causes the thow out bearing to wear out...



i tell people when sitting at a red light put it in neutral and let out the clutch, yes it takes a half a second longer to start moving when it turns green but still... better then taking apart the car just to switch out a 15$ part (idk the price of it but it was 15 for my 240sx)

 

Yeah no need to ride around coasting in gear with the clutch pedal pressed and as stated above, personal preference as far as coming to a stop. Without matching revs you are putting more stress on the synchros, but really that is what they are there for. So again personal preference, do you want a tranny that doesn't need to be rebuilt in a shorter period of time, but even though I like to match revs downshifting to a stop it is completely unnecessary on the roadway, but makes for good practice if/when you ever decide to take your vehicle out on to a circuit or even an auto-x course.

 

I could be wrong here, but if someone is unsure of even how to shift/downshift I seriously doubt they are going to know what terms like "heel-to-toe" and "blip throttle" mean!

A little more of a plain explanation or an explanation of those types of terms may be in order for those such as the OP who ask such questions. He apparently knows at least one of those terms, but some people may not have a clue about either.

I'm just sayin...

 

For any given gear and any given road speed, your engine is spinning at a given RPM. Study this first.

e.g.
3rd gear @ 60 mph = ??? RPM
4th gear @ 60 mph = ??? RPM
5th gear @ 60 mph = ??? RPM

Once you know this information, you will know how hard you have to blip the throttle for a smooth downchange. Basically you want to match revs and road speed. THIS is the logic behind why you do throttle blipping.

What I'm saying is if you're familiar enough with your engine and transmission's quirks/habits, you can forego downshifting in sequence (5-4-3) and just go directly to your desired gear (5-3). All you need to do is blip a little higher, so that when you engage the clutch in 3rd the engagement is still smooth.

 

Why use the clutch when downshifting? Just increase RPMs when going through neutral and slip it into lower gear. Use to do this with old Datsun 210. Neat when it works. A lot of gear crunching when it does not.

 

Cliff's note version:

Shifting from 5th to, say, 3rd or 2nd gear can put more stress and wear on the synchros because the difference in rotational speed between those gears is greater than if you went from 5th to 4th, then to 3rd. Therefore, shifting up and down in sequence will decrease wear on the synchros. However, synchro wear can be minimized if you can match the rotational speed of the input shaft to the output shaft prior to shifting into the next gear. In order to do this, you need to learn a technique known as "double-clutching."

Doing a simple rev-match, ie. rev the engine so that the engine speed matches the transmission speed for a given gear while the clutch is disengaged (clutch pedal pushed in) will do nothing to reduce wear on the synchros. Doing so only helps decrease wear on the clutch disk and decrease driveline shock once you re-engage the clutch (release the clutch pedal).

In order to really understand why, you first need to understand how a manual transmission works. And I don't feel up to writing a lengthy description on how this works. You can probably find several websites that explain it.

edit: here is a good website that explains how a manual transmission works: http://auto.howstuffworks.com/transmission.htm

 

Synchromeshes eliminated the need for double-clutching, but yeah doing it will save 'em.

For the rest of us, a proper blipped downshift and correct clutch engagement will do the same thing.

 

Coasting on the clutch is usually not a very long period of time. It's not like we're talking about standing on the clutch while you sit at red lights for 5 minutes at a stretch...and even doing that how often does the throwout bearing wear out before the clutch does?

Of course "best practice" is to have the car in gear whenever you're moving...like GD3_Wagoon says...in case you need to make a move! I don't usually downshift to stop the car, but when I'm approaching a light, I will hit just the brake until the RPM gets below 2000 and then clutch/neutral.

To the original question, my impression was always that the manual says not to skip gears out of concerns you'll lug or over-rev, but in practice there's enough overlap that this seems unlikely. I've always just picked the appropriate gear for the situation regardless of what the last gear was.

 

jzerocsk, +1 for you. I especially liked this part:

>>>I've always just picked the appropriate gear for the situation regardless of what the last gear was.<<<

As long as you match your RPMs/Speed, this works for me. Over 140K miles on original clutch on my Accord with this method. I always go up the gears one at a time (just a habit I don't want to relearn) but IMO going down the gears one at a time is unnecessary. As a young man I was told one reason to go down the gears one-by-one was to save on brake wear. Nowadays, what costs more to replace, clutch or brakes?

Now, I am not an engineer so if I am wrong, I concede the point to superior knowledge but given the mileage I have gotten from my clutches and brakes in the past, I am still NOT changing my style of shifting. To quote some wise fellow: In theory, there is no difference between theory and reality. But in reality, there is.

 

This is the first car I've purchased new, and I must be getting snobby for it. But almost every day I come on this forum I find a new reason NOT to buy a used car!

 

Clutch/synchro/bearing replacement costs a heck of a lot more than brake pads. Unless you absolutely have to utilize engine braking (to remove some of that load/heat from the brakes) or need to be in the proper gear to stay in the power band (braking for corner to then accelerate out), I'd recommend just leaving it in gear while braking, and once you get to 30 or 40, use the clutch and shift into the gear you want to be in (you said 3rd). No need to go sequentially through every gear.

A lot of people like to use track techniques (double-clutching, rev matching, etc) on the street which is fine but not really necessary. Some techniques like rev matching may ease synchro wear if you get it right, but others like double-clutching and trail-braking actually introduce additional wear on some items. And some of these techniques are as much about not upsetting the balance of a vehicle at the edge of its traction envelope as they are about reducing wear. While track driving is all about being on that knife-edge of traction as much as possible (and thus not upsetting that balance is critical), this situation is rare on the street and the associated techniques aren't necessary.

 

Agreed 100%

This is why I don't believe heel-and-toe is all that helpful on the road. In my experience, for H&T to be really effective, you need to be braking pretty hard. Half-assed H&T on the streets, where I typically don't approach 70% of max braking power, actually killed its effectivity for me on the track - and I had to relearn it, but only after I learned threshold braking first. Half-assed H&T can even mess up what smoothness it was supposed to bring.

Rev-matching and blipping are also kind of pointless if you're not accelerating after you do the maneuver IMO - the point is to engage a lower gear without any juddering through the driveline (i.e. engine braking) so you can go back on the throttle ASAP, not hit the brakes. Hence, a blipped, rev-matched downshift is really only useful for overtaking on the freeway.

The same logic applies for H&T - normally on a track you brake hard, blip, downshift...then end your braking and get on the power.

 

I like to rev match just because it provides a smoother experience for the passenger (aka the wife). I have never found much use for heel-toe in street driving. I think for most day-to-day drivers provides little benefit and is a potentially risky technique for the uninitiated. Most of the time I just downshift to where I'd expect to be coming out of the turn and leave it at that.

 

+1... i was about to say the same thing.. beat me to it :P

no need to rev match in daily driving situations... as a DD it only needs to get you to your destination.. no one needs to stay in the powerband while driving to work