Me vs. my friend (Who is stupid?)
Registered User
Joined: Sep 2002
Posts: 447
Likes: 0
From: San Jose, CA
Originally Posted by Spoolin Z
You and your friend are both wrong actually.
Both you and your friend will wear your syncros by rev matching that way. In order to properly rev match a downshift to put no wear on your syncros you should:
1. Press in the clutch
2. Select neutral
3. Release the clutch
4. Blip the throttle
5. Press in the clutch
6. Select the gear
7. Release the clutch
You can do this within a fraction of a second with some practice. I taught my girlfriend to do this over a year ago and its made her downshifting much smoother.
Your way is better than his because its smoother, however you're still causing your syncros to do some work. If you do your method while braking, its not as bad (many road racers will do this because its the fastest way to slow down). Of course true road racers only care about their tranny lasting for the race they're currently in.
Both you and your friend will wear your syncros by rev matching that way. In order to properly rev match a downshift to put no wear on your syncros you should:
1. Press in the clutch
2. Select neutral
3. Release the clutch
4. Blip the throttle
5. Press in the clutch
6. Select the gear
7. Release the clutch
You can do this within a fraction of a second with some practice. I taught my girlfriend to do this over a year ago and its made her downshifting much smoother.
Your way is better than his because its smoother, however you're still causing your syncros to do some work. If you do your method while braking, its not as bad (many road racers will do this because its the fastest way to slow down). Of course true road racers only care about their tranny lasting for the race they're currently in.
not double clutching like you should
lolz.
have you ever been on a race track?
Spoolin Z...
It IS pointless to double clutching on our cars. Double clutching might have been beneficial on older cars, but it is completely pointless on out tranmission.
Simple rev-matching should do the job.
.
It IS pointless to double clutching on our cars. Double clutching might have been beneficial on older cars, but it is completely pointless on out tranmission.
Simple rev-matching should do the job.
.
If this was the 40s, or early 50s, I could see this "discussion". The 40s/early 50s were the last time cars required double clutching.
Its 2007: no, you don't need to double clutch!
Its 2007: no, you don't need to double clutch!
Originally Posted by Miko
Does double clutching really wear the disk, pressure plate, bearing, or other components?
Registered User
Joined: Jan 2007
Posts: 418
Likes: 0
From: Atlanta, GA
Originally Posted by Spoolin Z
the synchros will do less work if you double clutch vs just straight downshifting. (I say less instead of none at all b/c noones perfect)
I typically stay out of these "discussions", but I'd be very interested in hearing why you think the above is true.
Registered User
Joined: Jul 2006
Posts: 51
Likes: 0
From: ma
Originally Posted by Mansmind
I typically stay out of these "discussions", but I'd be very interested in hearing why you think the above is true.
When you do a simple rev match downshift, the green shaft (input shaft) matches the road speed which are the blue gears on the yellow shaft (output shaft). However the two shafts are connected by the red shaft (the layshaft) which matches the speed of the input and output shafts within the transmission. By just doing a simple rev match downshift you match the green shaft with the yellow/blue shaft however the red shaft is still spinning at the previous gears speed (slower) because that is the last speed at which the clutch was engaged. This means that your synchros will have to do some work to match the speeds of all three shafts (as they were designed to do).
When you double clutch, the green shaft (input shaft) spins with the red shaft because the clutch is engaged in neutral. (clutch pedal up with shifter in neutral). Once you push in the clutch and select the lower gear the green and red shafts are still spinning at the same speed and connect to the yellow/blue shaft. This means that the synchros will have to do little to no work to make all three shafts spin at the same speed since you did most of the work for them.
If this still confuses you, I'll try to find a simpler diagram that I can make a description for.
Registered User
Joined: Jul 2006
Posts: 51
Likes: 0
From: ma
Originally Posted by G35_TX
Yes. Your pushing in the clutch twice and releasing it twice instead of once. It's like pushing on the brakes twice you get more wear than once. It's not worth it to save the syncros when the syncros are made for it. You will burn your clutch out faster this way.
Synchros aren't expensive themselves, however it is very labor intensive to drop a tranny and pull it apart to replace individual synchros. So when the time does come, expect to spend no less than $1500 on a tranny rebuild. Of course this is something that will only occur many years/miles down the line.
Registered User
Joined: Jul 2006
Posts: 51
Likes: 0
From: ma
Originally Posted by fr0ng
not double clutching like you should
lolz.
have you ever been on a race track?
lolz.
have you ever been on a race track?
Here is a video of some of the techniques I practice while driving on the track.
http://www.youtube.com/watch?v=0j-3xIZK-Bk
(notice the pumping of the clutch twice during the heel toe downshift).
A clutch will last 150k of miles if you drive it properly. Double Clutching I can promise will cut the life in half. I have been driving standard cars for over 18 years and never had a issue with Syncros till my 04 G35 which had the known Syncro problem.
The Syncros in our Tranny are designed to not use Double Clutching. THERE IS NO REASON to do this. So stop spewing BS. We are not in the 50s anymore.
The Syncros in our Tranny are designed to not use Double Clutching. THERE IS NO REASON to do this. So stop spewing BS. We are not in the 50s anymore.
Originally Posted by Spoolin Z
It will put more wear on your throwout bearing and pressure plate fingers, however these two items should be replaced at every fresh clutch install (despite being able to use them for at least two clutch installs). Both of these items are included when you buy a new clutch and both will outlast the actual clutch disk by a good amount. Therefore, it is costing you nothing more to double clutch and its saving some wear on your sychros.
Synchros aren't expensive themselves, however it is very labor intensive to drop a tranny and pull it apart to replace individual synchros. So when the time does come, expect to spend no less than $1500 on a tranny rebuild. Of course this is something that will only occur many years/miles down the line.
Synchros aren't expensive themselves, however it is very labor intensive to drop a tranny and pull it apart to replace individual synchros. So when the time does come, expect to spend no less than $1500 on a tranny rebuild. Of course this is something that will only occur many years/miles down the line.
Registered User
Joined: Jan 2007
Posts: 418
Likes: 0
From: Atlanta, GA
Originally Posted by Spoolin Z
Here is why:
When you do a simple rev match downshift, the green shaft (input shaft) matches the road speed which are the blue gears on the yellow shaft (output shaft). However the two shafts are connected by the red shaft (the layshaft) which matches the speed of the input and output shafts within the transmission. By just doing a simple rev match downshift you match the green shaft with the yellow/blue shaft however the red shaft is still spinning at the previous gears speed (slower) because that is the last speed at which the clutch was engaged. This means that your synchros will have to do some work to match the speeds of all three shafts (as they were designed to do).
When you double clutch, the green shaft (input shaft) spins with the red shaft because the clutch is engaged in neutral. (clutch pedal up with shifter in neutral). Once you push in the clutch and select the lower gear the green and red shafts are still spinning at the same speed and connect to the yellow/blue shaft. This means that the synchros will have to do little to no work to make all three shafts spin at the same speed since you did most of the work for them.
If this still confuses you, I'll try to find a simpler diagram that I can make a description for.
When you do a simple rev match downshift, the green shaft (input shaft) matches the road speed which are the blue gears on the yellow shaft (output shaft). However the two shafts are connected by the red shaft (the layshaft) which matches the speed of the input and output shafts within the transmission. By just doing a simple rev match downshift you match the green shaft with the yellow/blue shaft however the red shaft is still spinning at the previous gears speed (slower) because that is the last speed at which the clutch was engaged. This means that your synchros will have to do some work to match the speeds of all three shafts (as they were designed to do).
When you double clutch, the green shaft (input shaft) spins with the red shaft because the clutch is engaged in neutral. (clutch pedal up with shifter in neutral). Once you push in the clutch and select the lower gear the green and red shafts are still spinning at the same speed and connect to the yellow/blue shaft. This means that the synchros will have to do little to no work to make all three shafts spin at the same speed since you did most of the work for them.
If this still confuses you, I'll try to find a simpler diagram that I can make a description for.
Registered User
Joined: Apr 2007
Posts: 267
Likes: 0
From: NYC
I'm still going to have to +1 on Spooling Z's explanation - the diagram explains how it was always explained to me, this is what I have always done...and I have a 360K mile clutch with original syncros on an '87 Golf to prove it
Originally Posted by 07TouringZ
I'm still going to have to +1 on Spooling Z's explanation - the diagram explains how it was always explained to me, this is what I have always done...and I have a 360K mile clutch with original syncros on an '87 Golf to prove it
Strange, I never did it this way and I had 389k on a old Nissan Pickup with the original clutch and syncros.
Registered User
Joined: Jan 2007
Posts: 418
Likes: 0
From: Atlanta, GA
Actually I think it's pretty simple. There was a time before synchros, double-clutching was necessary. Now we have them, and it's not.
Yeah, I suppose it will save wear on the synchros, but that IS what they're there for. Last thing I double-clutched was a tractor.
Personally, I've driven vehicles in excess of 300k miles with no issues whatsoever on a stock clutch/transmission. Being that I've never experienced a synchro problem in the last 24 years, I think I'll use the advantage of having the synchro.
Yeah, I suppose it will save wear on the synchros, but that IS what they're there for. Last thing I double-clutched was a tractor.
Personally, I've driven vehicles in excess of 300k miles with no issues whatsoever on a stock clutch/transmission. Being that I've never experienced a synchro problem in the last 24 years, I think I'll use the advantage of having the synchro.