Lee and I have opposite theories about double-clutching on down gear changes. This is a neutral discussion, I just want to know what everyone else thinks about the topic..
Cheers 馃槑
[Edited on 20-11-2004 by oval TOFU]
sax 路
If it means a smoother downshift then why not?
Flying VW 路
If you enjoy fitting thrust bearings it's worth it. :thumb
sax 路
If you prefer fitting gearbox bearings instead, don't do it.
buzzbug 路
on a vw or a semi?
Che Castro 路
i thought thats what syncromesh is for 馃檪
Canni. 路
Have to do it quite a bit...gearbox worn out 馃檨 so beneficial as I guess its a lot better than crunching in the gears...
oval TOFU 路
Can everyone elaborate a bit on thier comments? - thrust bearing and gearbox bearing replacement? (I know thrust bearing would be easier to replace!)
buzzbug its manual che Castro From my understanding, doesn't it reduce the wear on the syncros as they don't have to 'work' as much to match the larger differences of speed the gears are rotating?
Flying VW 路
The thrust bearing slides over the Gear Box input shaft. When you use the Clutch, the fork moves the bearing into contact with the Clutch housing and it releases the grip on the Clutch Plate.
So every time you use the Clutch the Bearing has to do some work.
They should last as long or longer then the Clutch, but I always replace them when I replace a Clutch.
In all honesty Double Clutching shouldn't really hurt anything.
As for not Double Clutching hurting the Bearings in the Gear Box. :duh I don't think so, it would only hurt the Gears and Synchros if there not meshing properly and there being crunched together.
But I do know a Young Driver who has destroyed two thrust Bearings. I don't want to name him but he has Numbers and stripes on his Car. :thumb
andrewh 路
I do it out of necessity.
Going from third to second is next to impossible without it. The gearbox crunches violently. Same with second to first.
Warrenm 路
The Vw gearbox will even let you change without using the clutch.
Just pick the right revs
Warren
Oasis 路
Warrenm wrote:The Vw gearbox will even let you change without using the clutch.
Just pick the right revs
Warren
any gearbox will except maybe an FSM niki...
zac_smits 路
always.
that's how i was taught to drive and i love the sound of it. especially if you go from 5th to 2nd in hard braking 馃榾馃榾 (in a 97golf)
plus with a gearbox that requires a knee hooked over it to keep it in 4th (64 notch).. double clutching just makes it more interesting 馃榾
zac
BLUE_62 路
Mines a bit of a yes and no. If i am putting around i usually just down shift as normal. If i am into it a little and am downshifting hard i will rev match and double clutch to save syncros. My gearbox is quite good for an original. Only problem. 2nd to 3rd quickly creates a little crunch, and 2nd gear syncro wont hold in gear under high revs. (if i am in 2nd and floor it to 40mph and back off, it'll knock back into neutral. If i am putting around it behaves nice. Its old. Its tempremental. Doubleclutching and rev matching certainly sounds better if ya racing around thou. Especially if u got an audience and your coming into a nice roundabout or a set of lights :thumb Thats my 2 bucks.
Robo 路
Its only nessasary if you have a crash box, or worn syncro's. If you have a syncro box, why bother. VW made the later box's syncro for a reason, so not so good manual drivers would have an easier time of it and not destroy their gearbox! In my old 56 you sometimes have to change into first (non syncro) on a steep incline, I do it then and then only!
Rob...馃槑
zac_smits 路
nah. i'm a young driver and when in town...if i rev in 2nd then drop it..i can make the car backfrire very nicely. then as you come to the lights sounding like a beefy harley..it just attracts looks.
so always..it's still great fun in the 97golf too.
Warrenm 路
I am not sure if some understand what double declutching is.
Perhaps the ones that drop into 2nd and sound like a Harley could explain what they do.
Warren
zac_smits 路
say you're in 4th gear...
and you go to change down to third (there are multiple ways of doing this...)
you press the clutch in..blip the throttle..and then slot the gearshift into 3rd 'predicting' the revs beforehand. ie..do the syncros job for it.
makes for smoother downshifts and better control i think.
zac
Warrenm 路
zac_smits wrote:say you're in 4th gear...
and you go to change down to third (there are multiple ways of doing this...)
you press the clutch in..blip the throttle..and then slot the gearshift into 3rd 'predicting' the revs beforehand. ie..do the syncros job for it.
makes for smoother downshifts and better control i think.
zac
Double declutching:
You are in 4th and wish to change down- you put in clutch- shift to neutral-let clutch out- push clutch in- then shift to 3rd.
This allowed time for gear sets to match speed on crash boxes.
It is not double de clutching unless the clutch pedal is depressed twice..
Warren
[Edited on 21-11-2004 by Warrenm]
zac_smits 路
yeh i missed a line there...
and you just push the clutch in far enough to pop it out of gear..
but i still blip the throttle before pressing the clutch again
Robo 路
Thats why it is a waste of time on a syncro box, thats what their for! unless the syncro's are worn and not working. I have heard that double clutching on a syncro box accellerates the wear on the syncro mechanisims, is this so?
Rob....馃槑
zac_smits 路
wouldn't have a clue mate
oval TOFU 路
I won't double clutch everytime I downshift, usually only when I skip a gear (ie:4th to 2nd). If I'm putting around, as Blue_72 says, I'll just downshift normally. Personal preference and 'if you can be bothered' I suppose...
Splitting hairs now: wouldn't it reduce some wear on the clutch as well since it doensn't have to press against the pressure plate (or driven plate or whichever) at such large different rates of rotation?
[Edited on 21-11-2004 by oval TOFU]
Robo 路
Thats right, but if you get it wrong and clash the gears, whats more expencive to repair, a clutch or the gearbox?
Rob...馃槑
Warrenm 路
Robo wrote:Thats why it is a waste of time on a syncro box, thats what their for! unless the syncro's are worn and not working. I have heard that double clutching on a syncro box accellerates the wear on the syncro mechanisims, is this so?
Rob....馃槑
Yes it "spins" synchros at higher speed and causes additional wear.
Warren
oval TOFU 路
Warrenm wrote:
Robo wrote:Thats why it is a waste of time on a syncro box, thats what their for! unless the syncro's are worn and not working. I have heard that double clutching on a syncro box accellerates the wear on the syncro mechanisims, is this so?
Rob....馃槑
Yes it "spins" synchros at higher speed and causes additional wear.
Warren
Aren't the syncros spinning whenever the gearbox is in motion anyway?