Alfa Romeo Owners Club of Australia Forum

On Sunday I had a great argument with a couple of club members over whether you need to double-declutch or not, or whether it is quicker, or some other somewhat (a couple of lagers were consumed by this stage).  I want to hear what you do when you drive a manual car - particularly on the track.

A couple of definitions by me - please argue if you don't think I've got it right.

Heel toe - matches engine RPM to the car speed in order for a smooth downchange without upsetting the balance of the car.  Procedure: foot on brake, clutch in, keep foot on brake and blip throttle with side of foot, select lower gear, release clutch while engine revs are roughly matched to the road speed.

Double de-clutch - is a heel-toe downchange, except when you 'blip' the throttle you do it in neutral with the clutch engaged.  This spins up the input shaft of the gearbox to match the speed of the output shaft so that when you select the lower gear it engages smoothly.  The blip still acheives the earlier goal of a smooth downchange without upsetting the balance of the car.  Procedure:  foot on brake, clutch in, select neutral, clutch out, keep foot on brake and blip throttle with side of foot, clutch in, select lower gear, release clutch while engine revs are roughly matched to road speed.

I used to only heel-toe on the track, but recently I learned to double-declutch as my road car 33 has a terrible second gear synchro.  On that car (and third gear on the race car) double-declutching is HEAPS faster, a bit of footwork but the change is very fast and (unless I screw it up) totally smooth.  I screw it up a bit too often, but I'm still learning.

The argument against seems to be that double-declutching is slower, and that if you need to double-declutch just fix your gearbox and get over it.

What do you think?  I'd particularly like to hear from the experienced race drivers on the forum.

Just to fire this up - here's some footage of Walther Rohl in the Group B Audi.  That left foot braking is incredible.  The crowds are just insane also.

Take "honda" for example at Philllip island - 5th to 2nd gear  - 7500RPM in 5th, breaking and going to 6000RPM in 2nd. With a 116 type gearbox, if you don't heel toe, then you can't get the car from 5th to 2nd without compression locking the rear wheels. To double clutch would make the 2nd gear syncho last a lot longer, but its slower, so I just replace the 2nd gear synchro (a lot...) And thats with an 116 gear box where the gears have been lightened so much that they look like swiss cheese...

JimN~

Both.

Heel/Toe is primarily to ensure you have no engine compression lock up on the drivien wheels by matching road speed to engine revs.
In a car with syncromesh (in good nick) you don't need to double, the syncros do the gear speed matching for you, you are just matching revs to road speed.

In the Dulux i double clutch back to 2nd to avoid grinding, sometimes to third - just trying to make the gearbox last.  If your syncros are good you don't need to double which is slower.  Doubling does match engine to road much better but it is slower.

Yep double de-clutch does take a fraction longer than just matching engine revs but it is a much better for the synchros.  So if you're a hard core racer looking for those extra 1/100 of a second surely you would only match the revs?  The only thing is this is all taking place whilst braking, so as long as the shifting process is completed during the braking zone the small amount of extra time it takes to double de-clutch will not have any effect on your lap time, on the way up is a different story. That's the way I look at it, 105 synchros are made at of some sort of cheese so I try to be as kind to them as possible.

I agree with Colin - in theory it shouldn't take any longer during your braking.  Maybe when I learn to brake a bit later I'll find it harder...

I also tend to skip gears on the big braking corners - e.g. at Honda I go fourth to second gear directly, no way my gearbox would handle that without double declutching.

Long threshold braking zones, no problem heaps of time, shorter braking zones (eg old turn one at winton, even sthn loop or water tower) it can make a big difference, also car speed makes a difference - the faster the car the less time available - ie blue thunder vs Dulux or 550 - there is a lot more time to do stuff in Blue Thunder (a lot more).  Even Honda or sandown t1 can get tight.

Don't get me wrong i am a double clutcher from way back - in fact i have to conciously think not to double but in certain cars and certain cnrs double will cost time. 

Yes, the syncros wear very quickly in a 116 or 105 and it's not long after a change and the grinding is back, and then the only way is to double or replace.

I think the bottom line is if you are in a syncromesh car with good syncros doubling is really redundant and could cost you time.  Rely on the sycros to match gear speed, a big rev on the down change to match road speed and slam it thru....

I've been double-declutching for 18 years, so i definitely find it faster than just heel-and-toe.  I can DD without thinking, I'd need to think to h&t.  I find when I'm right up it, while DDing I can literally change gear as quickly as my hand can move the gear lever if there was no resistance at all (which of course is the result when you get it right anyway).

DD is much smoother than h&t also i find, but that maybe cause I'm more experienced at DD.  I think the braking is a good point also, and one I bought up when we were having our slightly-drunk-and slightly-heated-discussion-about-it.  Under hard braking you have ample time to DD through every gear.  But as said, with a fast car, that may be a different scenario.

Either way, either technique is an absolute necessity on the track, or even fast road.  I can change down smoothly in a half-second, and still be pulling 5 grand in the lower gear, right in the meat of the power.  try letting the clutch out without blipping the throttle while you do that as you're turning in.

Hmmm.  I have always heel-toed, and find it quite comfortable to do.

I have never even tried the double declutch.  Maybe I should be trying it.  I was under the impression that the only people with the need for this skill drove something with a 16 speed road-ranger g/box.

I was taught to DD by my Dad, who'd learnt drive in cars that required it.  And he probably assumed that one day I would have a car that also required it.

Once he saw that I could do it, he taught me how to change gear without the clutch, which is something relatively easy to do, but only if you're pretty good at double declutching.  He also said "don't EVER do this in a Japanese car".  Sorry Mum.

You're probably thinking "why would I ever need to change gear without the clutch".    It's come in handy for me once when I had to nurse a car home with a buggered clutch.  Also, I have a mate back home in NZ who has done Formula Ford, now doing Formula Toyota (or whatever it's called), he said that in FF, he was always left-foot-braking and changing without the clutch, and if you weren't doing that you'd be back of the field. 

It's not something I do at all nowadays, but as far as I'm aware it doesn't harm the gearbox at all if you get it right.  Happy to be corrected on this.  (Dad if you're reading this, feel free to use the clutch on my car at Phillip Island in December!)

It's not Formula Toyota, it's the Toyota Racing Series.   Looks like a good class, wish they had it here.  http://www.toyotaracing.co.nz/ (http://www.toyotaracing.co.nz/)

Quote from: Phil Baskett on November 20, 2007, 03:49:29 PM
I was under the impression that the only people with the need for this skill drove something with a 16 speed road-ranger g/box.

And anyone who drove a formula 1 or rally car before sequential gearboxes presumably?  No snychros on racecars baby!!

Hmmm, maybe that'll be the slogan to replace my "Alfasud" sticker on the back of my 90.  "No synchros on racecars baby!!"

cos the synchros are shot............Maybe that's why no-one else wanted to buy the car before me.  "The synchros are gone...."  "Not a problem"

QuoteI can DD without thinking, I'd need to think to h&t.

Sheldon always told me he was a big fan of DDs.  Didn't know it had anything to do with gearboxes though.

I tripped across this by mistake, thought it might be of interest.

Taken from http://www.hiperformancestore.com/guiboDSclutch.htm



Double Clutching, or how to not wear out your syncros.

     This was originally written and posted on gtv6.org which is now alfagtv6.com. Since then I still have not managed to wear out a single syncro. They seem to last nearly forever if you do the work for them by double clutching whenever possible. Save the syncros for when you really need them. For example during a critical drag race you DON'T want to double clutch on an upshift despite what Dominic says in The Fast and The Furious. This is when it's acceptable to put extra wear on the syncros.

     I seem to have run into quite a few people who are not too clear on the method of double clutching, nor the reasons.
Well the reasons are simple, double clutching will greatly reduce your syncro wear, in fact if you could do it perfectly all the time it would totaly eliminate all syncro wear. In many transaxle cars with worn syncros, double clutching is the only way you can downshift at speed without grinding the gears, and in some really worn out gear boxes it may be the only way you can shift period.
Before we get started lets have a basic review of what goes on in your gearbox. Inside there are two main shafts, lets call them the INPUT shaft and the OUTPUT shaft. The Input shaft spins at the same speed as the engine when the clutch is engaged (that means pedal up). The output shaft is connected solidly to the wheels via some other gears, half shafts, etc. so it spins at what we can call road speed. Get it so far? Input shaft spins at engine speed, output shaft at road speed.

     Now when your car is in nuetral these two shafts are not connected which is why you can rev the engine up in nuetral with the clutch engaged and the car does not go anywhere. In order to make the car move we need to connect these two shafts together, we do that with one of the gears. Lets do that with first gear in ohh, say an 85 GTV6. With the car at a stop, first gear selected and the clutch DISengaged (pedal down) the shafts are connected but not turning. Remember they can't be turning because the output shaft spins at road speed and the car is stopped. The input shaft is not connected to the engine because the clutch is disengaged.
Now, we will let the clutch out and the car will start moving because the clutch by definition engages and CONNECTS the engine to the Input shaft of the transaxle (via the driveshaft of course. Now the Input shaft is turning at engine RPM and the Output shaft is also turning but a whole lot slower due to the 3.5:1 first gear. That means that when in first the input shaft spins 3.5 times for every one time the output shaft spins.
Now the fun part. We rev our already warmed up car up to 6300 RPM in first and shift into second (just a normal shift, we are not double clutching yet). Now what happens? As we all know this will result in a big drop in engine RPM. IN fact it will drop to about 3600 in this particular year GTV6. However the output shaft continues to spin at the about the same speed because road speed has not changed much during the shift. However what is the input shaft doing? Well, it's spinning a whole lot slower, it just dropped from 6300 rpm to 3600 rpm. So, what caused it to slow down while the clutch was in during the shift? If you guessed SYNCROs your right! The syncro is simply a metal ring that uses friction, like a break to slow down the input shaft to match the speed of the output shaft so the two shafts can be connected by the gear. Every time you shift up a gear the syncro slows the input shaft enabling it to be reconnected to the output shaft. If the syncro is worn and it can't get the shafts to the same speed you will hear that horrible crunch and grinding sound.

     Now the more the syncro has to slow down the input shaft the harder its job is. A shift at max RPM causes a much bigger RPM change then a shift into second at 3000 rpm. That means that the syncro will have a much easier time dealing with a 3000 RPM shift then a redline shift. So your car is much less likely to grind with a low RPM shift and will have much less wear on the syncros. Of course it's not fun to drive around at low RPM all the time so we need another way to reduce the load on the syncros, and I am getting to that.
Now lets consider a downshift. A downshift is just the opposite of an upshift meaning engine RPM and Input shaft speed will increase. That means the syncro will need to speed up the input shaft which is a whole lot harder then slowing it down on an upshift. On an up shift the input shaft slows down on its own and the syncro just helps it along but on a down shift the syncro has to speed that shaft up a couple thousand RPM and that's very hard on it. Again a key to minimizing the wear is to shift at the lowest speed possible and only go down one gear at a time. A shift from 5th into second at 40 mph will require the syncro to speed that shaft up a whole lot more then a shift from fourth to third at twenty for example. In fact even if your syncros are new they may give trouble in that 5th to second scenario and won't last long if you do that.

     Understand that that was just a very basic non tech description of how the transaxle works but should give enough info to understand double clutching.
Double clutching is a method of reducing the load on the syncros by matching the speed of the input shaft to the output shaft manually during shifts. During an upshift it will be neccesary to manually slow down the input shaft and during a down shift you will need to speed it up.
How do we do this? It's easy, at least in theory although it will take a little practice. First of all lets sit in the car, start the engine and rev the motor with the clutch engaged (pedal up) and the car in nuetral. Right now you are speeding up and slowing down the input shaft. Whatever speed the engine is spinning, thats the speed of the input shaft. As soon as you depress the clutch pedal the input shaft will start to slow to a stop since it is no longer connected to the engine. After you depress the pedal wait a moment for the shaft to slow down to make things easier on the first gear syncro which will need to stop the input shaft. Now lets get the car rolling by letting the clutch out and run the car up to max RPM in first. Now we are going to DOUBLE CLUTCH into second gear. First let off of the accelerator press the clutch pedal in and move the shifter to nuetral. Let the clutch pedal out and wait a moment. Now engine RPM and consequently Input shaft RPM will begin to drop. Thats exactly what we need. In an 85 GTV6 we know that it will need to drop to about 3500 RPM to be equal to the output shaft, in a Milano 2.5 it's closer to 4000rpm due to its closer gear spacing. Once the engine is approaching to desired rpm (it's better to do this too early then too late) press in the clutch pedal and select second gear. If you time it right the syncro will only have to slow down the input shaft a couple hundred RPM instead of the 3500 it needs to slow during a normal shift. Even the worst syncro can handle this job so you can understand why this method reduces wear and enables shifting with really worn syncros.
Practice upshifting this way and soon it will be second nature and you will be able to do it really fast with no wear or damage to your transaxle. You will soon learn just how long you have to pause with the clutch out in nuetral for the RPM to drop the right amount. It's a little different in each gear and for each year but basically it's about about a two second pause for the first to second shift and about one second in all the others except fifth. Shifting into fifth the RPM drop is so minor that double clutching is not needed but if you want too, make the pause as short as you can and it will be about right.

     OK, now the hard part the double clutching down shift! This is what separates the amatures from the experts.
Really it's not that bad Lets start with a fifth to third shift at around 60 mph. This is the typical passing scenario. First of all the car at 60 will be at about 3000 rpm in fifth. In third gear it will be turning around 4000 rpm at 60, that means we will need a 1000 rpm INCREASE.
We start out by pushing in the clutch pedal, putting the car in nuetral and letting the pedal out. Now we can speed up the input shaft to 4000 RPM with the accelerator pedal. Once it is at the required RPM or close enough push the clutch pedal in and select third gear, then let the pedal back out. This really takes a lot of practice but once you get it you can downshift to second or third from and other gear smoothly with no gear crunching or grinding. When practicing this don't get too hung up trying to look at the the tach and match rpm, you just need to blip the throttle to an RPM higher tnen needed and let it settle into the desired range and then select the gear before the input shaft slows down too much.
Good luck and lets preserve those syncros.

Quote from: Evan Bottcher on November 20, 2007, 04:59:52 PM

QuoteI can DD without thinking, I'd need to think to h&t.

Sheldon always told me he was a big fan of DDs.  Didn't know it had anything to do with gearboxes though.

Yes, he loves the double d's.....

What the hell?  My girlfriend reads this forum sometimes you know, you bastards. 

regarding the speed of the input shaft, Is this why transaxle synchros always go so quickly, because it's got all the momentum of the driveshaft to speed up/slow down?  I've asked a couple of people with Porsche 944s (they're also rear transaxle aren't they?) and they've never had probs with synchros.

I heard that painting flames down the side picks up more time than double clutching.

Doug Gould

Quote from: Doug Gould on November 23, 2007, 06:45:17 PM
I heard that painting flames down the side picks up more time than double clutching.

Most definitely, probably picks up more DDs as well. 

Quote from: Sheldon Mcintosh on November 23, 2007, 06:34:40 PM
regarding the speed of the input shaft, Is this why transaxle synchros always go so quickly, because it's got all the momentum of the driveshaft to speed up/slow down?  I've asked a couple of people with Porsche 944s (they're also rear transaxle aren't they?) and they've never had probs with synchros.

This is why I think a rear clutch is better.  When the clutch is disengaged for changing gears, the synchros only have to speed/slow down the clutch, but with a front mounted clutch(like the 924/944 etc I think) the synchros have to speed up/slow down the entire driveshaft and the clutch.  Still doesn't explain why the Alfa synchros wear out ???

I thought that transaxle cars had a much smaller flywheel, as the driveshaft itself adds to the flywheel effect - is this true?

Quote from: Scott Farquharson on November 20, 2007, 12:10:29 PM

Yes, the syncros wear very quickly in a 116 or 105 and it's not long after a change and the grinding is back, and then the only way is to double or replace.

I think the bottom line is if you are in a syncromesh car with good syncros doubling is really redundant and could cost you time.  Rely on the sycros to match gear speed, a big rev on the down change to match road speed and slam it thru....

Scott do you own shares in the Syncro company, If you only DD when the box starts to grind you have already started the process that leads to rebuilding the box. I have DD since I first started driving on every change down, except on the few cars I could do clutchless changes. (PS do not do cluchless changes in 116's, if you don't get it perfect you end up with a broken box, just ask Alan Jones he destroyed heaps of boxes in the ingus car, Bondy never broke 1).

If you want long life from your Syncro's then DD, my 116 GTV has done over 440,000kms and has never had a synco put in it, I also have never had to replace the diff, a common failure on Transaxles. It would be fare to say that the car was driven with mechanical simpathy all its life, but was always driven hard with a 180hp motor, it was use for sprints, hammered over 10's of thousands of km of mountain passes, including gravel and even used for recey and setups no rallys, dirt not tarmac.

Anthony

Quote from: a sharp on November 25, 2007, 11:03:30 AM

Quote from: Scott Farquharson on November 20, 2007, 12:10:29 PM

Yes, the syncros wear very quickly in a 116 or 105 and it's not long after a change and the grinding is back, and then the only way is to double or replace.

I think the bottom line is if you are in a syncromesh car with good syncros doubling is really redundant and could cost you time.  Rely on the sycros to match gear speed, a big rev on the down change to match road speed and slam it thru....

Scott do you own shares in the Syncro company, If you only DD when the box starts to grind you have already started the process that leads to rebuilding the box. I have DD since I first started driving on every change down, except on the few cars I could do clutchless changes. (PS do not do cluchless changes in 116's, if you don't get it perfect you end up with a broken box, just ask Alan Jones he destroyed heaps of boxes in the ingus car, Bondy never broke 1).

If you want long life from your Syncro's then DD, my 116 GTV has done over 440,000kms and has never had a synco put in it, I also have never had to replace the diff, a common failure on Transaxles. It would be fare to say that the car was driven with mechanical simpathy all its life, but was always driven hard with a 180hp motor, it was use for sprints, hammered over 10's of thousands of km of mountain passes, including gravel and even used for recey and setups no rallys, dirt not tarmac.

Anthony

I should clarify, I, out of habit, have always DD, in all cars I am driving...and I have always DD in the Dulux, however from competition point of view in a number of situations/cnrs, it is faster to simply sacrfice the syncros in a 105/116 gearbox for the speed and just heel/toe and not DD, and as Jim said just change them regularly.  If you have a gearbox with good syncros (ie. not an alfa) you can do this and it may be quite a long time before you need a change.  I'll think you'll find in say the WRX club that not many would DD because it's simply not an issue in a WRX.

If you simply want to save syncros then by all means DD all the time.

My point above was that once you have grinding then the only way not to grind is to DD.  Not that the way to save a gearbox once there was grinding was then to DD.

I think it depends on your objective - if you want to just make syncros last then sure DD all the time, but as i said on some cnrs there is a penalty for DD and a simple heel/tow and let the syncros do the work is the fastest.

I'm a bit late to discussion, but I will add my two cents worth ...

I always understood that double-declutching was when you didn't use the brake ie changing up gears in a non-synchro box (or a truck) or using the gears to slow you down when downchanging.

I always understood hee-toe as incorporating the brake pedal into your double-declutch.

In the first instance I double-declutch, or use the gears to help slow me down when I'm driving my road car. Often you find yourself in a situation in the road where you've slowed down in traffic (coasted) without using the brakes and need to select a lower gear, so I just blip the throttle, double-declutch and make a smooth gear change.

In a racing situation you never you the gears to slow down - that is what the brake pedal is for!  ::) As a few have said before in this thread, you will always be on the brakes long enough for you to double-declutch on the downchange. Ok, I might double-declutch every gearchange - I will often go straight from 4th to 2nd for Honda Hairpin at Phillip Island, but I will always double-declutch - its smoother and easier on the machinery. And as club racers we have to look after the gearbox - no one can afford to get then rebuilt every second race meeting...

Honestly I would be very surprised that anyone in our form of racing would not double-declutch, whether we are using synchro or dog boxes.

have a look at the "foot-cams" they sometimes deploy in the V8 Supercar coverage. All those cars use 6 speed Hollinger dog-boxes. You will see that they flat change up the gears without using the clutch (though some drivers have taken to using the clutch for across the gate changes - 2nd to 3rd and 4th to 5th. When they change down gears all the drivers with one exception are using the clutch to select the gears and are thus double declutching on their heel-toe changes.

You may ask who that one exception is? well as far as I know Greg Murphy is the only V8 driver who left foot brakes, which means he isn't using the clutch at all and must deploy what we consider in this thread to be the true "heel-toe." I'm not quite sure how he does it (I believe it's a common practice where sequential boxes are used, eg old Lola Champ Cars from 2006 and before) but he must be good at it as I reckon it would be tough on the gearbox...

[quote ........

I always understood that double-declutching was .......  or using the gears to slow you down when downchanging.

..Um no, this is using the engine braking capability of the car to produce a slowing effect. Taken too far the compression of the engine will cause the driven wheels to lock up - its not how you drive a racecar. Anyone can "flatshift" given the hardware and software required to make this work (like in a v8 supercar). On an standard alfetta gearbox however the heel toe or DD maneuvers discussed in this thread are actually required to have any chance of shifting from (say) 5th to 2nd at high revs smoothly.

JimN ~

Jim, I think we are getting stuck on semantics, or if you prefer terminology.

As I said I never use the gearbox to slow myself down on the track, but I do use the gearbox to "help" me slow down on the road and limiting use of the brakes - usually I'll double declutch down from 4th to 3rd and only incorporate the brakes for a heel and toe change back to second as I'm coming up to an intersection.

Maybe that is why (on my 01 Honda Integra Type R with 110K) I'm onto my second clutch but still on my first set of front brake rotors...  ::)

As a long time driver trainer (heavy vehicle mostly), you should never double de-clutch a synchromesh gearbox, you are getting the synchro's to work twice as hard as they were intended/desgined to.   Just for interest sake, Volvo trucks will void warranty if they can prove that a driver is double de-clutching one of the synchromesh truck gearboxes.

It has been an eacceptable practice, that when synchro's are getting a bit dodgy that you double de-clutch, but it isn't the correct thing to be doing, but it does aid the trasmission selecting a gear.

Why do synchro's wear out? Normally because people select a gear at a too high gear, e.g. using the gearbox as a brake.  Syncro's are designed to help match speed of gears, however if the variation of speed is too great then the synchro's wear out very fast.

The heel-toe is the prefered version (on a race track)

I'm struggling a bit with this concept

Quoteyou should never double de-clutch a synchromesh gearbox, you are getting the synchro's to work twice as hard as they were intended/desgined to

The way I see it is if collar and gear are speed matched (double-declutching) then the only wear occurring on the synchro-rings is from the transverse movement of the collar, however if the speeds are not matched (normal shifting) then the synchro-rings get the same wear from the transverse movement plus the additional wear from the rotational movement.

QuoteWhy do synchro's wear out? Normally because people select a gear at a too high gear, e.g. using the gearbox as a brake.  Syncro's are designed to help match speed of gears, however if the variation of speed is too great then the synchro's wear out very fast.

If this is the case, which I don't disagree with, then how does reducing this speed difference as much as possible (double-declutching) wear the synchro out twice as fast?

Any chance of a further explanation Big Trev?

I am no mechanic, but I have a good understanding of the workings, so I will try to explain what I mean.  If you push the clutch in and pull the gear lever out of gear then put the gear lever in a position of the next gear you want, then as soon as the gear of the selector starts pushing agains the synchro's then there is friction to slow down or speed up the gear you are trying to select - correct? 

When the sped difference is at its lowest or there is least resistance then the gear will be selected - correct?

If at the point when the gearbox is in neutral and you are pushing against the syhncro and then you de-clutch again you are taking the spin off (or power from) the input shaft which means the gearbox is free-wheeling and you then let the clutch out again the input shaft starts to spin a different speed and the syhncro is sitting there spinning aagainst the cone (or gear being selected), thus causing extra wear.  It is like having 2 bites at the cherry if you like.

Hope that is easier to understand.  All transmission manufacturers highly disapprove of double de-clutching a synchro box, do a google search and see what I mean.

QuoteIf at the point when the gearbox is in neutral and you are pushing against the synchro and then you de-clutch

Sorry Trev I still don't follow, why are you pushing against the synchro at this point in the sequence,  During the time at which the gearbox input shaft is re-connected to the engine (clutch pedal up then clutch pedal down) the gearbox should be in neutral-> no pressure on the selector forks-> no pressure on any synchro rings.  It's only after the input shaft has been disconnected from the engine (clutch pedal down) after the speed matching has been completed that the synchro should begin to make contact

As long as the gearbox is in neutral during the speed matching process I still can't see how this creates extra wear.  If this was the case then wouldn't just revving your engine in neutral whilst stationary wear out our synchros as well?

Awesome explanation Mate. I feel like I understand a little bit of what happens in a gearbox now :-)

One question. Bearing in mind my own experience with alfa's goes back to my first car - a 1971 105 Berlina bought on L plates in 1979, why is it that Alfa's need to be double clutched when down shifting, especially from third to second.

Are the gear boxes just notoriously bad for synchros, or is it because the passion of us alfa drivers makes us drives the cars to the stage where the double clutch is required to extend the life of the synchros.

Interested in your opinion, I've always DC down the gears with all my alfas, just out of habit.

Catch ya

Shane

QuoteAnyway, I'm sure someone will want to argue,

No arguments here, great explanation (although it was a bit of a struggle trying to read it all on my mobile phone last night!)

Quote from: shane wescott on January 15, 2008, 09:40:21 PMOne question. Bearing in mind my own experience with alfa's goes back to my first car - a 1971 105 Berlina bought on L plates in 1979, why is it that Alfa's need to be double clutched when down shifting, especially from third to second.

Are the gear boxes just notoriously bad for synchros, or is it because the passion of us alfa drivers makes us drives the cars to the stage where the double clutch is required to extend the life of the synchros.

OK, As I said my mechanics knowledge is basic, so I accept what you are saying TurboGTV - thanks ( my knowledge is more related to heavy vehicle)


Shane, the main reason synchro's wear out is from over use, 2nd gear is the gear that most people use for cornering, and as most people use the gearbox the slow down (instead of using the brakes), the 2nd gear synchro's cop a flogging.