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ngn
Hi,
I've had my elantra for about a week. It's my first stick car and I'm learning all the cool parts about driving a manual. Someone on this board mentioned to me in a previous post that when downshifting into first, I should double clutch it. I have also heard that when downshifting into lower gears in general, you should try to rev match.

I have practiced a little on downshifting and I find that the following works best for me. As I'm slowing up, I push the clutch in, shift down a gear, and while the clutch is still in, I give it a shot of gas to get the RPMs up, then slowly release the clutch so that it matches the RPMs. I find this is easiest when going from 4th to third or third to second. I've found that if done right, this results in a very smooth downshift.

However, I have read about double clutching (especially into first gear), which requires you to shift into neutral first, then give it a shot of gas, then down shift.

What's the difference? Why should I go into neutral first before giving it a shot of gas, when I can just give it a shot of gas while the clutch is down before sliping the clutch into gear?

Why use one method over the other? What's the difference between rev matching and double clutching? Aren't they both really the same thing?

Is my technique of giving a shot of gas while the clutch is down wrong? Should I be double clutching instead while downshifting through the gears?

Thanks for the help.
ricerrx7
What you are doing is rev-matching. It's good for preventing clutch wear during down shifts, and making the engagement sooner.

Double clutching is used for making the actual shift smoother. When you rev the engine with the clutch pushed in, the gears in the trans don't do anything in correlation to the engine. But when you rev the engine with the clutch out (in neutral) the gears also speed up, and prevent wear on the synchro's. Large trucks and really old cars have to double clutch because (as far as I understand it) there are no synchros.
ngn
So, rev matching as I am doing it is fine for the higher gears.

Is double clutching ALWAYS required to downshift into first. Sometimes I'm moving so slowly that second gear will just bearly cut it. I find it easier at this point to shift into first. I usually get a very nice shift and smooth transition into first. So, even though, when going very slowly, I can get a nice transition into first, is it still necessary to double clutch? Am I messing up my gears by not double clutching when shifting into first when rolling very slowly? Should I worry about it? I don't feel anything alarming and I only do it when I'm moving very slowly. But, I don't want to wear on my synchros.

Or, is double clutching only necessary when downshifting into first at higher speeds. If so, at what speed should I double clutch rather than simply shifting into first. How can I tell that I should have double clutched? In other words, what will it feel like if I don't double clutch and downshift into first, when really I should have double clutched? Right now, whenever I've downshifted into first, it's felt pretty good and I haven't double clutched. How will I know that double clutching is necessary? Will I hear grinding of gears? Will the car shudder?

thanks, evey post is very helpful.
cclngthr
QUOTE (ricerrx7 @ Sep 13 2006, 06:30 PM)
What you are doing is rev-matching. It's good for preventing clutch wear during down shifts, and making the engagement sooner.

Double clutching is used for making the actual shift smoother. When you rev the engine with the clutch pushed in, the gears in the trans don't do anything in correlation to the engine. But when you rev the engine with the clutch out (in neutral) the gears also speed up, and prevent wear on the synchro's. Large trucks and really old cars have to double clutch because (as far as I understand it) there are no synchros.
*


Most of the early 30's to late 40's cars you had to double-clutch. This action is similar what our automatic trans does when it shifts.
Tirolerpeter
QUOTE (ngn @ Sep 13 2006, 09:09 PM)
So, rev matching as I am doing it is fine for the higher gears.

Is double clutching ALWAYS required to downshift into first.  Sometimes I'm moving so slowly that second gear will just bearly cut it.  I find it easier at this point to shift into first.  I usually get a very nice shift and smooth transition into first.  So, even though, when going very slowly, I can get a nice transition into first, is it still necessary to double clutch?  Am I messing up my gears by not double clutching when shifting into first when rolling very slowly?  Should I worry about it?  I don't feel anything alarming and I only do it when I'm moving very slowly.  But, I don't want to wear on my synchros. 

Or, is double clutching only necessary when downshifting into first at higher speeds.  If so, at what speed should I double clutch rather than simply shifting into first.  How can I tell that I should have double clutched?  In other words, what will it feel like if I don't double clutch and downshift into first, when really I should have double clutched?  Right now, whenever I've downshifted into first, it's felt pretty good and I haven't double clutched.  How will I know that double clutching is necessary?  Will I hear grinding of gears?  Will the car shudder?

thanks, evey post is very helpful.
*



Good questions. Everything posted so far in response to your original question is correct. You have been "rev matching" and it has obviously made for smooth CLUTCH engagement. But, as has been noted, you are not "double clutching." Downshifting from any higher gear to any lower gear is facilitated by the synchronizer rings in your transmission. As you push the shift lever from the higher gear position into the lower gear position the synchro rings are forcing the internal shafts of the transmission to turn at the same speeds. This is most noticable on shifts from 2nd down to 1st, if you are moving at more than a couple of mph. You can actually hear the lower gear shaft "whine" as it tries to speed up. I'm sure you can feel the resistence in the stick as you force the lever into the slot for the lower gear. The "double clutch" procedure works to not only match the revs for clutch engagement, but it also helps to speed up the internal shafts carrying the gears thus making it easier for the sychros to smoothly engage the shafts carrying the lower gear. In fact, done properly, you don't need the sychronizer rings at all. As noted, on some older vehicles there were vehicles that had synchros in only the higher gears, or in some cases, none at all (usually big trucks).

I posted the following previously. You might find it helpful. The stuff on double clutching is toward the end.

Manual Trans Basics


When I teach a “first timer” to drive a manual trans I take them to a nice level empty parking lot and proceed as follows:

After explaining why a clutch is needed, I show them how to start from a total stop without touching the gas or stalling the engine. Then I make them do it themselves several times. Then I get them to do standard up-shifts while still not touching the gas pedal. This makes them understand that there is no need to use excessive engine RPM to get the car rolling. Of course, that then graduates into normal starts, and up-shifts using proper amounts of gas.

Since the Elantra has five fully synchronized forward gears, it is very easy to drive and shift both up and down through the gears. While some members are annoyed by the “soft’ feel of the clutch, it is a very easy clutch to work with. And, it can be “tightened up” a bit with the “clutchvalvectomy.”

For normal driving, there is no need to use more than 1500 – 2000 RPM at start up. I think the vast majority of clutch wear occurs when a driver uses too much gas and too much clutch slippage at virtually every start. Some drivers also allow slippage between engagements of gears while rolling. That is totally unnecessary. After you get going in first, there is no need to slip the clutch again on subsequent shifts. If you allow the clutch to engage fully as you move off in first gear, you can give it as much gas as you want, run the revs way up, and get moving very quickly without beating up the clutch. This car does have that annoying RPM hang that can cause some up-shifting issues, but it is not so severe that it normally causes a problem. Regardless of how high you run the RPM, up-shifting into second is just a matter of clutching, while simultaneously letting off the gas, then slide (don’t jerk)the stick into 2nd and bring the clutch up while not letting the RPM drop too far. The next three shifts are the same.

Down-shifting is where people encounter issues. At fairly slow shift speeds the synchros allow pretty smooth engagement into a lower gear. As soon as you move the shifter into the next lower gear, you should be bringing the revs up as you engage the clutch (This is known as “rev matching”). This is to prevent the “forward head jerk” that an inexperienced driver can often produce when they grab a lower gear but don’t give enough gas. As drivers get more experienced, and want to drive more “aggressively” they try to speed up their shifts and shift at higher RPMs. This is where the problems begin. When the shifter is pushed too quickly and the synchros are stressed, you can encounter either a “grind” or even a missed shift.

So, how to avoid jerkiness, engage lower gears smoothly, not lose power as you shift, and do so at higher RPMs? Simple: Double Clutch. Describing this takes a lot of words, but is actually quickly and easily done. And, after a little practice, becomes totally automatic. BTW, don’t keep the clutch depressed (like sitting at a light), unless you are actually shifting. It creates wear on the throw-out bearing.

A little digression: I like driving a stick because I get to choose not only what gear I want the transmission running in, but also exactly when I want to be in that gear, and at whatever RPM I want to be in based on power demands of the situation. (Like passing another vehicle with oncoming traffic, or wanting engine braking on a hill or on very slippery surfaces.) I actually double-clutch all my shifts both up and down through the gears. It is just a totally ingrained habit. In truth, it is really not necessary to double-clutch this transmission on up-shifts. The synchros do an excellent job virtually all the time. Down-shifting is another matter.

Double-Clutch down-shift procedure:



When going from a higher to a lower gear, you need to increase engine RPM and spin up the transmission internally so that you don’t force the synchronizer rings to work too hard, and possibly create a “grind” and/or avoid the dreaded “head jerk.” When you decide you need to down-shift use the following sequence:

Push down on the clutch; slide the stick into neutral, release the clutch and at the same
time “blip” (give it a little gas to bring up the RPM) and then immediately push the clutch in again (you have just increased the internal speed of the transmission) now slip it into the lower gear, and while giving it more gas, bring the clutch back up. You have now engaged the lower gear, not lost power, and helped the synchros engage internally. You know you are doing it right, when you feel no resistance on the stick as it slides into gear, and there is no “jerk” as you release the clutch and hit the gas.

This is the same for every shift from fifth gear down to first. It is best to practice this by first working on a 5 – 4 downshift, and as you get smoother work on 4 – 3 and so forth. Keep in mind, that the RPM difference between each gear increases as you go to lower gears. So, as you work your way down through the ratios, you need apply a bit more RPM at the point where you have the stick in neutral, and you are “blipping” the gas.

Give it a try, and you will drive more smoothly, and be able to wring more performance out of your vehicle (after you master the technique of course.)
fgummett
here is some sweet video that was posted on EXD : Heel & Toe + Double Clutching with Gary Sheehan...
SWortham
QUOTE (fgummett @ Sep 14 2006, 05:50 AM)
here is some sweet video that was posted on EXD : Heel & Toe + Double Clutching with Gary Sheehan...
*

Impressive stuff. Gary posts over at NASIOC, he's good.
cobas
There's a section of the transmission between the clutch and gears. It's small and light, but it's still there and that's why you need the synchros to help engage gears. By rev-matching, you are spinning the engine to the new RPM (approx) for the next gear. But since you pushed the clutch, there's that small section between the clutch and gears still spinning at the old RPM. To spin that part up, you have to rev-match with the clutch engaged (in neutral). So shift into neutral (release clutch), rev-match, shift into next gear, thereby using the clutch twice and hence the name double-clutching. If you don't do this (most people, most of the time) you are using and wearing the synchronizers.

I don't think there's anything special about first gear except that it has such a high gear ratio and thus the RPM-mismatch from the next gear is greater.

1-2: (3.62 - 2.05) downshift RPM Difference: 77%, Max RPM: 3680
2-3: (2.05 - 1.37) downshift RPM Difference: 50%, Max RPM: 4340
3-4: (1.37 - 1.06) downshift RPM Difference: 29%, Max RPM: 5030
4-5: (1.06 - 0.84) downshift RPM Difference: 26%, Max RPM: 5150
Tirolerpeter
While I have used the "heel-toe" method many times in the past, it is really only useful for competition driving. For the average driver, a good smooth down-shift
double clutch procedure is adequate. I have seen many people use the "heel-toe" method rather badly. They really don't benefit, and often just beat up their clutches and trannys. Beginners should NOT focus on "heel-toe" shifting. They should master normal shifts, and "double clutching" before venturing further.
ngn
This is some great info. If I rev match without double clutching, is the wear on the synchros really all that significant? You mention that most people don't double clutch. Do I really need to double clutch ALL the time, or is rev matching enough to get me by without much wear on the car. I assume that no rev matching at all results in the most wear?

If I never rev matched, where would the most wear be: The engine? The clutch?

Also, Tirelopeter, you mention not to use any clutch slippage between gears when rolling and when moving up through the gears. Are you saying that I should pop the clutch on all gears after first gear? This would make for a rather bumpy ride. I have found that for smooth shifts, I need to let the clutch up easy and gently. Of course, not as slowly as first gear, but especially moving from first to second, I need to go a little easy on the clutch or I'll lurch a bit. Are you saying that this will cause unnecessary wear? I can feel just a moment at the friction point while moving up through the gears, and I try not to accelerate during that point, just enough gas to hold the proper rmps. I do most of my acceleration after letting out the clutch fully, but I don't just pop it, I do just slip it just a little bit, I think. If this is wrong, how should I be letting up on the clutch in higher gears?
---------
Also, I would think that one of the benefits of heel-toeing it would be that you can break through the downshift. If I am slowing down and I want to downshift, unless I heel-toe the downshift, there is a moment there when I have to release the break to give it a shot of gas. This affects the slow down and also, might be confusing to a car behind you who thinks that maybe you are going to speed up when all of a sudden you downshift.

On the same note, how do most of you slow down? My friend drove my car and I noticed that he likes to shift into neutral and brake a lot. It seems that whenever he needs to break, he shifts into neutral, whether it be around very tight turns or slowing down to turn off a road, etc.

A lot of other people I have talked to say they like to downshift instead. I think I would like to learn how to downshift properly. I've tried my friend's neutral technique and I don't like its lack of control. I also don't like the idea that if I suddenly need to accelerate, I have to shift into gear from neutral.

Could you give me some procedure to practice? Let's say I am coming to a stop sign in the far distance and I am in fourth gear. How should I proceed to slow down? Many people say that when starting out, you should push the clutch EVERY time you hit the break. That doesn't seem to make sense to me. Isn't that the same as putting it in neutral every time you hit the break? So, how do you usually slow down to make a turn, or slow down to a stop? When in the process do you hit the clutch? Howabout going around a tight turn on the road? If you need to break during the turn, do you really need to hit the clutch at the same time? Doesn't seem to make sense to me. All help is appreciated.
cobas
I was going to say what I usually do, after driving a manual 3 years, and I just realized... I DON'T REMEMBER!! YES!!! Finally, I've reached the point where I just drive and I don't remember how I shift or don't shift.

Anyway, yeah if you're just starting out, maybe you need to double-clutch into 1st gear but otherwise just rev-matching is fine and forget the rest. I rev-match, I double-clutch into 1st and also into 2nd and 3rd when the car is cold (less crunchy that way), and I 'heel-and-toe' sometimes but that's not something to practice in traffic. When i need to brake and downshift, I try to get the downshifting done early and then just brake. The only way to brake and downshift perfectly at the same time is heel-and-toe, which is a pain.
SWortham
I rev match and heel and toe downshift. I never double clutch though. I never thought it was so important with today's modern synchros.
Bobzilla
QUOTE (SWortham @ Sep 14 2006, 02:54 PM)
I rev match and heel and toe downshift.  I never double clutch though.  I never thought it was so important with today's modern synchros.
*


I agree 100%. I've tried a few times to double clutch, especially when I was fighting a cold crunch this past winter but never saw any benefit. As long as the synchros are in decent shape than there is really no reason to need to double clutch.
Tirolerpeter
ngn as you get more and more used to driving stick, you will find less and less need to slip the clutch on upshift. As you clutch and shift up, you need to release the gas. Although this car tends to "hang" a bit on the revs, by the time you have the lever in the next higher gear and lift up on the clutch, you should need no slippage at all. Maybe you are getting on the gas too soon after shifting up. Any slippage, intended or otherwise, is wear on the clutch. The absolute worst thing to do in terms of wear is to accelerate while slipping the clutch. Unless you are pulling out onto a road, and suddenly see a semi bearing down on you, don't do it. It is one of the reasons I recommend getting rid of the clutch restrictor valve. You can practice rapid clutch release (not "popping it") in the higher gears first. As you get better, you can gradually get it down to the 1 - 2 upshift all the time.

Don't "heel - toe" you are not ready for it and don't need it.

Your friend is wrong to clutch any time he is braking. It is especially bad to de-clutch and brake in curves. If the curve is tight enough to require a lower gear to pull out of it, downshift just before the curve (double clutching here is useful), keep the clutch engaged, and use the brakes only enough to help slow the car down to an appropriate speed for the curve. Then, use the gas to pull yourself through and accelerate back up to where you should upshift again. The rule of thumb for any kind of driving, whether stick or automatic, is to brake down before the curve, and then pull through and out with the throttle (but not too much!). Anytime you are rolling, you should be in an appropriate gear. If you are approaching a stop sign, get off the gas, start braking, and as you get down to about 25 mph, just put in the clutch, and finish your stop. Brake pads are a lot cheaper than clutches to replace. The only time to use downshifting for braking (despite how much fun it is) is when you are on a long down-grade or are trying to maintain control on slippery roads.

Bobzilla, if you are not experiencing any "benefit" from double-clutching, then you are likely not quite getting it right. It is a skill that is best personally demonstrated by someone proficient at it. It's kind of hard to "talk" someone through it on line. Although, I sure have tried over the last couple of years. Keep in mind, I have been driving manual transmissions for over 43 years. I have owned, and driven trannys that were three speed (no sychros in first or reverse) four speeds (early ones also had no 1st gear synchros) 5 speeds, 6 speeds, and 6 to 12 speed truck trannys (some with NO synchros at all). Proper double clutching allows for seamless gear changes at all power levels. It allows you to utilize the really best part of your engine's power band without any jerkiness, or gear crunching. I can run most vehicles up through the gears from first to fifth and back down again without changing actual road speed, and without a passenger noticing anything other than the change in engine sound. It just takes practice.
ngn
Tirolerpeter, I notice that I am getting better as time goes on (I've only been driving a stick for like 6 days.). Just to get something clear though. When shifting up, are you applying any gas at all while releasing the clutch or are you only applying gas once the clutch is FULLY released. I find that for smooth transitions, I sort of apply some gas while lifting the clutch and apply more and more gas as I lift up until it is fully up and then I really accelerate. All of this happens rather quickly, but I'm pretty sure I'm starting to apply the gas as I lift and the clutch starts to bite, and then lift off the clutch smoothly and apply for full accerlation. Are you saying that instead, I should hold off fully on the gas until I'm fully off the clutch? Of course, popping the clutch is not the way to go, so there is some smoothness to the release, and therefore, some slippage (unless I'm misunderstanding what you mean by slippage). What I mean, is that there is a very quick moment spent where the clutch is partially engaged. Otherwise, you'd have to pop it to avoid any semi engagement of the clutch. I do get fully off the gas when I push the clutch in, then shift, then get back on the gas very slightly while releasing the clutch and when I feel it start to bite, I start to give it a little more gas, then fully release and gas it up. All pretty quickly (though slower from 1-2nd gear). I have found it easier to get off of 3 and 4 and 5 quickly, then going from 1-2. To avoid a lurch in the lower gear, I need to be more gentle. Don't get me wrong, I'm never reving the engine without going anywhere. I feel like power is always being transferred well to the wheels (Sometimes, since I'm new at it, I feel myself accidently acellerating too early when the clutch is biting and I don't get a lot of power and I know I'm wearing the clutch). Most of the time, I don't feel any slipping to the gas, but I do feel myself begining to apply the gas when I reach the biting point of the clutch, then releasing the clutch more and more and accelerating through it.

How can I tell if I'm wearing the clutch too much? How can I tell the difference between a nice shift and a shift with too much slippage? I would like to identify any of my bad habits very early on. Thanks for taking the time respond!

As for breaking: So, it seems from what you say, that, in general, unless I need more control going down a long hill or coming to a long slow stop, that I don't really need to downshift all the time. Also, I should only really clutch in at the last moments before fully breaking (around 25mph). Is that correct? In that regard, once I get up to speed, I should drive it like an automatic and not to worry about the clutch all that much for minor breaking, breaking around curves and such--I should only worry about it when coming to a full stop, right? I think my friend got into the habit of going into neutral because he was scared of stalling out at slower speeds, but stalling out seems pretty impossible as long as you are rolling. I'll try to take the car out and stay in gear until I really need to stop, then clutch it. Downshifting, though, could come in handy if I anticipate a need to accelerate out of the slowdown quickly.

One final question, what about a quick emergency stop? I find the need to clutch in during this circumstance to avoid stalling. There's no real time to downshift and no use doing it. So, shouldn't I get in the habit of clutching when I have to do an emergency break? But for minor, temporary breaks, no clutch is necessary? It will take some time to train my brain, I guess. Thanks.
fgummett
For an emergency braking situation, "if in doubt, both feet out"... in other words brake AND clutch. You want to avoid stalling the engine so that whatever the emergency, you still have the option of quickly driving or reversing away BUT ideally you hold off depressing the clutch until the very last second as the engine will help to stop you more quickly and with more balance. As you have ABS, press as hard as you can on the brake and just before you are completely stopped floor the clutch... if you stopped quickly and the engine is still running you did it right. Its part of the driving test in the UK but to this day (only 22 years not yet 43!) I will still practice it from time to time on a nice empty stretch of road... try a slow speed stop at first and gradually build up to higher speeds.

DON'T use the clutch on a bend... as above do all your braking before the bend and use the gas to pull/push you through the bend. Hitting the clutch and/or brakes in the turn is very likely to throw the car off balance when it already has reduced grip and you could go for a spin. Even with the stock tires I find my '05 GT hatch one of the best cornering cars I have driven in a while.. especially since I went with the 19mm Tib sway bar and rear strut brace.

For regular braking to a stop (at a light for example), look well ahead down the road and if you see a red traffic light, ease off the gas and if needed use the brake gently at first... chances are you may not need to come to a full stop at all... but if you do, gradually increase brake pressure until the car starts to slow then you may find you can actually ease back on the brake until you are almost completely off it by the time you come to a complete stop... completely drop the clutch just as you come to a complete stop.. this results in the smoothest stop for you, your brakes, your car and your passengers. Try it out in a car park where you are not worried about stalling and having cars backed up behind you blush.gif Once stopped at the lights, gear in neutral, clutch up and hand-brake on. As above, it wears your clutch throw out bearing to hold the clutch in and also consider what could happen if you were rear-ended while holding the car with a depressed clutch and holding it on the foot brake...

You are absolutely right about it being highly unlikely to stall so long as the car is rolling. Another advantage manuals have over automatics is the "bump start"... you can roll down a hill (or get a few friends to give you a push) with the engine off, in 2nd gear with the clutch in... then turn the electrics on and let the clutch up quickly to turn the engine over and fire it up without the starter.

How are you doing with up hill starts..?

Good Luck... I still really enjoy driving a stick shift and sometimes I just go driving for fun thumbsup.gif
Tirolerpeter
ngn I think I see your "jerkiness" problem.

You said: "I do get fully off the gas when I push the clutch in, then shift, then get back on the gas very slightly while releasing the clutch and when I feel it start to bite, I start to give it a little more gas, then fully release and gas it up."

Don't start to apply gas until the clutch is actually engaged. It is useful to "lead" with some gas when downshifting (rev matching), but when upshifting, "rev matching" requires REDUCING the rpm down to the proper level. In time, you will just "feel" when it is time to start adding gas. You will eliminate that "slippage" that you think you need, because by adding gas too soon, you would "jerk" if you let the clutch all the way in. Hey, I think you are doing great for "6" days of stickshift driving.

Yes, in an emergency stop, you need to hit the clutch and brake at the same time to avoid stalling the engine. It is a reflex that you will develop in time.

You said: "How can I tell if I'm wearing the clutch too much? How can I tell the difference between a nice shift and a shift with too much slippage?


OK, the rule is, any time the clutch is slipping, like in starting up, it is wearing. Any time it is fully engaged, it is not wearing. Of course, you need a bit of slippage at start-up, but every other shift requires no slippage at all if you have the gas/gear/speed equation in equilibrium. It comes with practice and experience. You would be amazed at how little "slippage" you actually need for the average, level road, non-racing start-up. I sold a 91 Honda Accord (my previous personal vehicle) with 203K miles on the original clutch and it was going strong when I sold it. I even did a good bit of trailer towing with that vehicle. The key is, as always, reduce slippage whenever you can.

A big mistake beginners make trying to make a fast start is to pour on the power while slipping the clutch. The right way (again, assuming no semi or train is bearing down on you) is to ease in the clutch smoothly and fully, and then you can "go for the red-line" before you upshift. You can do this at every shift, but just don't let it slip.

Fgummett makes a good point. Whenever you are stopped for more then a few seconds, put the stick in neutral and take your foot off the clutch. Even with the clutch fully depressed, there may be some slight slippage of the clutch friction disc on the flywheel. Most importantly, you are wearing out the throwout bearing anytime you sit with the clutch depressed. The business about being rear ended is also something that could have damaging effects. Also, while waiting to turn across traffic, keep your wheels straight ahead. If you are hit in the rear, you won't be pushed into on-coming traffic. There is also less "start-up" effort for your engine and clutch to overcome when the wheels are straight. Try it. Keep working on your technique, and like Cobas said, in time it all becomes totally unconscious and automatic.
southpawboston
QUOTE (SWortham @ Sep 14 2006, 03:54 PM)
I rev match and heel and toe downshift.  I never double clutch though.  I never thought it was so important with today's modern synchros.
*



QUOTE (Bobzilla @ Sep 14 2006, 04:10 PM)
I agree 100%.  I've tried a few times to double clutch, especially when I was fighting a cold crunch this past winter but never saw any benefit.  As long as the synchros are in decent shape than there is really no reason to need to double clutch.
*


+1 !!!

in 21+ years of driving (all manual trannies) i have never worn out a synchro, and like swortham, i rev match and heel-toe, but don't double-clutch. besides, double-clutching just takes longer, no matter how proficient one may be at it. one could also make the argument that it puts twice the wear on the clutch release arm, the throw-out bearing, and the clutch master and slave cylinders (parts that the elantra is known for having problems with).
Tirolerpeter
QUOTE (southpawboston @ Sep 14 2006, 10:57 PM)
+1 !!!

in 21+ years of driving (all manual trannies) i have never worn out a synchro, and like swortham, i rev match and heel-toe, but don't double-clutch.  besides, double-clutching just takes longer, no matter how proficient one may be at it.  one could also make the argument that it puts twice the wear on the clutch release arm, the throw-out bearing, and the clutch master and slave cylinders (parts that the elantra is known for having problems with).
*


I disagree. I would bet that you actually spend more actual time on the clutch while you heel-toe then I do on a double clutch, and the consequent "rev matching" (which is part of double clutching) is more precise with the double clutch then with the heel-toe action. But, like medieval scholars arguing over "the number of angels that fit on the head of a pin," we really would have to have a real life "face off" on this. BTW, in slow to moderate driving I actually don't even use the clutch on the initial gear disengagement. I just slip it into neutral and then depending upon whether I am up or downshifting, either let the rpm drop, or "blip" it and then I just clutch once.

In any case, I think the major "crunching issues" that new MT drivers develop are likely due to attempted (and mostly unnecessary) "speed shifting" and attempts to engage a lower gear at rather high speeds. I have seen many new and poorly trained more experienced drivers approach a left or right turn at 30 to 40 mph, clutch, start to brake, and immediately (while still coasting at those speeds) attempt to engage 1st or 2nd. The "whining and complaining" of the sychros is painful to my ears. If they just waited with the lower gear engagement until they were down to the much lower actual turning road speed, the synchros wouldn't have to work so hard, and most "crunching" would not occur.
Bobzilla
I feel like the "young'un" in this crowd. I've had manual trannies since I was 14, so that only gives me . . .17 years? I have to say my personal favorite for clutch/shifter feel was my 2000 Sonoma with the 2.2L. Direct connection on the trans, light predictable clutch feel. Completely unlike the Elantra!
silet
Since this the newbie section I'll throw in my stupid question. Reverse has no synchros, so is that why I have to double clutch to get the gear in? I have to do the same in the Integra.
Bobzilla
Actually Tel, if you slide into 1, then 2, then 1 it will slide right into reverse.
silet
I'll try that, but I think pumping the clutch and tapping the gas may be quicker. I have to tell my wife to try it, because she can't get reverse in unless she moves forward for even just an inch.
Tirolerpeter
QUOTE (silet @ Sep 15 2006, 09:02 AM)
I'll try that, but I think pumping the clutch and tapping the gas may be quicker. I have to tell my wife to try it, because she can't get reverse in unless she moves forward for even just an inch.
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Actually, if you have it in neutral with the clutch engaged and "tap" the gas, you are spinning up the internal shaft and you will likely get a nasty "crunch" as you try to engage reverse. Every tranny is a bit different, so before trying to engage reverse, clutch then slip it into a synchronized gear (I tend to use 3rd since it is a "forward then back" motion to get to reverse) and then with the clutch still down, slip it into reverse. Usually works. Again, another gear may line up the reverse gear in your particular vehicle better, so you have to try different combinations.
silet
Okay, I'll try it. The Acura gets it about half the times. It's rare on the Elantra.
southpawboston
from what i understand, reverse does get a synchronizer, but a primitive one. it is designed only to stop the spinning of the reverse gear from an idle engine speed (since that is really the only time you would ever want to go into reverse). i may be wrong however...
Bobzilla
I've been doing that process (my 1-2-1-R) pattern since my Tempo. It's just second nature to me now.

On the FS trucks both of them would crunch going into reverse if you let the clutch out before trying to shift into reverse. ALWAYS. . . .but if you went 1-2-1 then reverse they were quiet as a church mouse.
ngn
I don't get the reverse issue? I just put it in reverse and it seems to work fine. Once and awhile, I'll think I'm in reverse, but then as I release the clutch to put it in gear, I get some crunching. All I do is go into neutral and then put it back into reverse. But, this is very rare. Most of the time, I just go into reverse. Sometimes the stick feels different than at other times when I slip it into gear. It's the same with first gear. Sometimes the stick feels a little bumpy when I put it up into first, and sometimes it's just smooth and I don't feel any resistance in the stick. Any reasons?

I've been trying to use some downshifting as I've been coming to stops. It makes for a bumpier ride, but I like the control and I like being in the proper gear for the speed. Does it wear more on my car? I know it helps the break, but whatabout the tranny getting more of a workout...any long term problems? When I have car sick prone guests in the car I think I'll avoid it and just break in whatever gear I'm in and then clutch it when I'm about to come to a stop and slip it into neutral.

One question, say I'm in 5th gear and I don't want to downshift. How slow can I go before I will stall? At what speed should I put the clutch in before coming to a stop?
cobas
The idle is about 1,000rpm when the car is moving, so I put it into neutral before it drops to 1,000. Now that I'm paying a bit of attention, I actually heel-and-toe a lot more than I thought initially. That makes the downshifts while braking a lot smoother. And yes, downshifting without rev-matching will wear the clutch more, and that's expensive to replace. As Peter says, brake pads are cheap.
Tirolerpeter
QUOTE (ngn @ Sep 17 2006, 09:24 PM)
I don't get the reverse issue?  I just put it in reverse and it seems to work fine.  Once and awhile, I'll think I'm in reverse, but then as I release the clutch to put it in gear, I get some crunching.  All I do is go into neutral and then put it back into reverse.  But, this is very rare.  Most of the time, I just go into reverse.  Sometimes the stick feels different than at other times when I slip it into gear.  It's the same with first gear.  Sometimes the stick feels a little bumpy when I put it up into first, and sometimes it's just smooth and I don't feel any resistance in the stick.  Any reasons?

I've been trying to use some downshifting as I've been coming to stops.  It makes for a bumpier ride, but I like the control and I like being in the proper gear for the speed.  Does it wear more on my car?  I know it helps the break, but whatabout the tranny getting more of a workout...any long term problems?  When I have car sick prone guests in the car I think I'll avoid it and just break in whatever gear I'm in and then clutch it when I'm about to come to a stop and slip it into neutral. 

One question, say I'm in 5th gear and I don't want to downshift.  How slow can I go before I will stall?  At what speed should I put the clutch in before coming to a stop? 
*


The crunching in reverse is what everyone is discussing here. It happens because the internal shafts of the transmission are spinning whenever the clutch is engaged. Stepping on the clutch, and slipping into another (synchronized gear) stops that spinning and prevents the crunch.

As for first gear, it depends just on where the transmission stopped spinning as to whether you feel anything or not. The "bump" you feel is the synchronizer activating to line up first gear. It is normal.

Downshifting to slow the car is cool, and useful in slippery conditions or to engage a lower gear for engine braking on a downhill stretch. While it "helps the brake" it does cause more wear on the clutch and synchros during each shift. If you are "shaking up your passengers" you are not doing it smoothly enough. Stick to simple braking for virtually all your speed reductions for longer clutch and tranny life.

You can comfortably slow the car (with the brakes) down to 25 mph while in 5th gear before stepping on the clutch. Of course, don't try speeding up again in 5th from that speed without shifting down a gear or two.
cclngthr
I think when downshifting as you slow down should not be at a speed where you can feel it. I would try this first: see which gear lugs the engine at a medium acceleration speed (see which gear lugs the engine at a certain speed) then keep that speed and gear in mind when you downshift. This way, the downshift does not destroy the clutch/transmission. Since I have the auto, I don't know the exact speed and gear.
cobas
Here's a short video of a gentle launch (gauges only).
http://www.youtube.com/watch?v=RXMYn78DRek
stauf
http://www.youtube.com/watch?v=rqtctkznYjk

try that.. tongue.gif rofl.gif

also, the only thing that 'should' be required to get into reverse, is to move the shifter into neutral. i find generally moving into the 1-2 neutral position lets me into reverse easily. sometimes 1st is required first tho. imo, poor reverse lockout design...
silet
When I mentioned about reverse above I meant at start up only. On both the XD and the Integra, there are times when the gear will not go in. Clutch depressed for start up and directly shifting into reverse! I ease off the clutch a bit and the gear then slips in. This happens on both cars.
fgummett
I also have occasional difficulty getting into reverse. Not every time but often I have to depress the clutch a couple of times... no biggie... reverse is not gear I want to engage by mistake anyway blush.gif

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