So I am thinking to myself, as I drive along in my new AB Mini that I picked up on Saturday, that, having read about double clutching and how you are less prone to damage the transmission synchornizers, it feels a bit wrong to just push the clutch in all the way and shift completely. There is just something that feels off about doing this the "easy" way. I have never double clutched before, and I know I'll catch heat from some of you for even bringing it up given my inexperience, but it just feels to me that I should learn (I tried it out a couple of times with no issues)...My two questions are the following: Should I experiment with this while the clutch is still pretty new (almost 250 miles) or just wait a few more hundred miles? Should I fool with this at all? Thanks. Now back to trying to move the grin from my face and come up with some more excuses to leave the house to drive.

 

Whats double clutching?

 

I think you should try power-clutching instead.

 

It's when you engage the clutch into neutral, then disengage it and go into the next gear (and then engage it again of course ). It helps match RPMs...also resulting in less wear on your syncro and other transmission parts.

 

Been driving manual trannys for nearly 30 years and never double de-clutched (never had synchro/gearbox problems either).....I wouldn't bother.

 

If you're worried about downshifting and matching revs, just blip the throttle via some heal/toe. If you do it right, all will match and be calm. If you do it wrong, the synchros will save you and you'll feel a lurch.

mb

 

Strangely enough I read from Click and Clack that it's a total waste of time in a car with sychro gears. They're designed to just depress the clutch and shift. No wear savings, or any savings at all.

 

I like this method......do it when needed...

 

I dont like double clutching. It seems like a lot of work for nothing. to me. Sure, matching up the engine with trans before you release the clutch is a GREAT idea, no question there. but you dont have to double clutch to do it. If you waiting for the engine to wind down, just hold the clutch in longer. otherwise, as was mentioned, heel-toe is a faster way to get the engine up to speed anyway(and more satisfying). I tried double clutching and it just was too much work when you can just hold the clutch in, or heel-toe to do the same thing.

also, wether some of you know it or not, the clutches/transmissions on these are pretty nice. Im pushing 70k miles. I race off the line quite a bit. a lot of open throttle shifting and my clutch/trans still feel great.

--my two cents--

 

God invented synchronizers so you don't have to double clutch. Really no reason to on a modern gearbox. Do it if it makes you feel sporty I guess.

 

addamaniac, syncro's work great when upshifting. The problem is that when you downshift, the syncro has to bear the entire momentum of the car when your puting it in a lower gear. Holding the clutch in doesn't work when the next gear needs to be 1k rpm higher. Heel-toe works great when your actually braking but sometimes, you need to drop down a gear (or two) to pass. That's when double clutching really helps. I can go from 6th to 4th with no jerk and without causing the syncros to work overtime.

 

I'm not advocating double cluthcing as a regular practice but if its of no value then why is the following a fact: I'm sure most of us have experienced that situation when sitting in neutral and trying to go into 1st or more often into reverse, it won't go in smoothly, either harder to go in or begins to grind slightly. What's the answer? Double clutch man. It goes in smooth as butter. Now before all the sage advice on taking it in to the shop rolls in, it happens at some point on just about any make tranny. I'm just sayin....

 

Hmm, very interesting responses. I surely thought that at least a few people would be very pro-DC, but I suppose I was mistaken. Thank you all for your responses. An additional clutch question, though: The manual suggests to be easy on the clutch during the first few hundred miles, if I remember correctly. What exactly does this entail? No quick shifting? No fast acceleration? Thanks again.

 

some of the newer MCS's come with two clutch pedals.

 

There is value to double clutching and heal/toe downshifting on the track. First, it stops the synchros from having to do a ton of matching when slowing down from high speeds. Second, the lurch created from NOT matching the revs upsets the balance of the car and your smoothness.

All that said, I heal/toe all the time on the street 'cause I love the way it sounds, feels, and makes me think I'm helping my transmission. Passengers like it, too, less lurching and fun blip noises.

mb

 

Double clutching when upshifting has always struck me as mostly just a cumbersome way to force you to shift more slowly. Yes, shifting more slowly reduces wear on the synchros, but you can just as well accomplish that by keeping the clutch on the floor and having some patience.

It's not like the MINI clutch disc and input gears weigh a lot since they're not from a semi-truck. Those are the parts the synchros have to accelerate when downshifting and decelerate when upshifting (to match the output gears attached to the wheels). Yes, if you match revs while the clutch is up and tranny is in neutral, then the synchros will have less work to do, but if you don't match revs then there will be no benefit.

 

will be learning to drive manual trans with this MINI (estimated delivery date 5/11), and have heard the "heel toe" thing before - what is it? Scared to death to drive in traffic!!

 

Flat-shifting is my favorite!

 

Everything I have read in the enthusiast magazines (Road & Track, Car and Driver, AutoWeek) indicate that double clutching is no longer necessary.

Years ago when transmissions were not as well designed and metalurgy (sp?) was not as advanced, double clutching helped reduce the wear on transmission parts.

If you like it and think it helps. do it. For the majority of drivers, I think slowing down your shifting a little and allowing the syncros to do their job is a better way to take care of your car.

 

Aha! That must be what my wife is constantly stamping on over there on the passenger side when we're on the Dragon.

Truth be told, double clutching is mostly a holdover from the days of unsynchronized trannies.

And, as has been said above, it's a useful way to downshift smoothly when the car is in extremis and a lurching downshift will introduce you to Mr. Uncontrolled Understeer.

 

double clutching is necessary for track use...quicker, smoother, and does not upset the balence of the car.

 

Double clutching was what you had to do to match revs AFTER you blew out your syncros by missing many of your single clutches. Also, there was typically no syncro on the upside of 1st gear, so you had to double up when downshifting into 1st. IMHO, unless you have great timing, double clutching at least doubles your chances of missing a shift and, yes, grinding your syncros. As for the syncros taking the load, I guess in theory double clutching may relieve this, but I have faith that BMW has built these well enough to withstand what we can dish out. As for heel/toe, I too would appreciate an explanation of what it is.

 

I am surprised at the misinformation here. Many of you are confusing two facts, some of you have it right (mostly the old guys like me). Double clutching is a hold over from non synchro transmissions. It is no longer necessary. Rev matching is common for enthusiasts and race drivers and can be used both up and down. Basically the idea is to keep the revs constant while changing gears, not to have the drop off of revs when engaging the clutch.

 

Taken from an article on Edmunds.com.....

A heel-and-toe downshift refers to a specific technique used to downshift a manual transmission car. It might seem bizarre to the general populace, but racecar drivers use it all the time. Once mastered, the heel-and-toe downshift offers the benefits of reduced vehicle wear-and-tear, better driver control and faster lap times on a racetrack.

The heel-and-toe downshift is a rather complex action involving both of the driver's feet, the driver's right hand, all three vehicle pedals and the gear shift lever. The purpose of the heel-and-toe is to smoothly match engine speed to wheel speed. Here is a generalization of how a normal person downshifts a manual transmission car.

Let's say Frank is driving his '01 Volkswagen Passat around town. He is approaching a right-hand corner while in fourth gear at 50 mph. He is going too fast to make it around the corner safely, so he starts braking until he drops the Passat's speed to about 25 mph. Frank sees on the tachometer that his engine revs are dropping too low, so he pushes in the clutch as he goes around the corner. As Frank thinks about accelerating, he realizes that the Passat is still in fourth gear, which isn't suitable for strong acceleration at such slow speeds. So he moves the shifter from fourth to second gear, lets out the clutch and motors away.

The problem with Frank's technique is that when he lets out the clutch, it is not going to be a smooth shift. The Passat is going to buck a little. Why? Because when Frank goes around the corner with the clutch pushed in, the engine revs drop to idle speed. When he releases the clutch, the mechanical locking effect between the engine and the front wheels (the wheels powered by a Passat) forces the engine revs to match the rotational speed of the rear wheels. In this case, 25 mph in second gear would mean the engine has to be at roughly 2,600 rpm. When Frank lets out the clutch after moving the shifter to second gear, his car's engine must instantly go from idle to 2,600 rpm. This sudden change causes the car to buck, as well as causing undue wear-and-tear on the clutch, transmission and engine mounts.

The simple solution for Frank would be to give the car some throttle before he lets out the clutch. Specifically, he should raise the engine speed to 2,600 rpm. This way, the engine speed is equalized to the wheel speed for second gear, making the shift much smoother. For racecar drivers, however, this technique is too slow and also means that when the car is going around the corner, the clutch is pushed in, a serious no-no in a racecar.

The racer's answer is the heel-and-toe downshift. The technique combines braking and downshifting at the same time. Using our example again, if Frank used a heel-and-toe downshift, he would have downshifted while he was braking for the corner. This way, he would have had power while he was going around the corner and he could have quickly applied more throttle once he exited the corner. These are critical elements to a racecar driver, but they can also be useful to any driver on the street.

Here is a step-by-step guide on how to heel-and-toe downshift. It will explain how to shift from fourth gear to third gear, though the technique will work for any downshift.

1. Begin braking for the corner with your right foot. The location of the pedals and the size of your foot will dictate where you position your foot on the pedal, but most likely it should be canted a little to the right, closer to the throttle pedal.
2. Push in the clutch with your left foot.
3. This is the hard part. With your right foot still applying pressure to the brakes, roll the outside edge of your foot outward and downward to touch the throttle pedal. The pedal design on some cars makes this easier to do than on others. Use the outside of your right foot to blip the throttle. Blipping the throttle means temporarily raising the engine rpms to match the wheel speed. The exact amount of revs needed is dependent on a variety of factors, but it is usually between 1,000 rpm to 2,000 rpm more than the current engine rpm for a one-gear downshift.
4. Move the shifter to third gear.
5. Release the clutch with your left foot.

As you can see, "heel-and-toe" is a misnomer. It actually involves the ball of your foot and the side of your foot. We'll be the first to tell you that heel-and-toe downshifts aren't easy. We've found that a good way to practice is to just sit in your car in your garage and pretend you are doing a heel-and-toe downshift with the engine off. Keep repeating the steps until you are familiar with the process. Once you are ready, try it out for real. Most likely, your early attempts will be botched. Keep trying, though. Practice each step slowly and then work your way to making them all one, fluid motion. Skilled drivers can execute a heel-and-toe downshift in less than one second.

The trickiest part is getting the correct amount of rpms to match the new gear. If you blip the throttle too much, the engine has too much speed compared to the wheels and is forced to drop down to the wheel speed when you let out the clutch. If you don't blip the throttle enough, the engine rpms are forced to rise up. Either way, you know you didn't do it right as the car will jerk a little.

You'll also know it when you did it right. A proper heel-and-toe downshift is so smooth and so satisfying that, once done correctly, you'll find yourself using the technique all the time. The great thing is that you don't have to be a racecar driver or be on a racetrack to use it. Additionally, using the heel-and-toe downshift technique on the street can improve safety. In certain emergency situations, you might be required to brake heavily and then accelerate quickly. By heel-and-toe downshifting, your car will be in the best gear to achieve maximum acceleration.

So, let's recap. It's fun to do. It improves driving safety. It reduces the amount of powertrain wear on your car. Other than the amount of time it takes to learn, there is no downside. What more could you want?

 

Thank you for the very goods explanation Big Daddy