More clutch paranoia: shift shock

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JusCruzin
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More clutch paranoia: shift shock

Postby JusCruzin » Sat Apr 02, 2011 12:39 pm

Been driving stick for about 2 months now, and still struggling with smooth downshifts. I'm hesitant about practicing rev matching much due to paranoia that shift shock from a poorly executed downshift could damage the car. Am I being overly paranoid? Does shift shock cause damage?

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Re: More clutch paranoia: shift shock

Postby Tups » Sat Apr 02, 2011 1:28 pm

What's a shift shock?
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Re: More clutch paranoia: shift shock

Postby six » Sat Apr 02, 2011 2:08 pm

You're being overly paranoid. While it is true that excessive shift shock can cause extra wear on drivetrain components, I doubt you are shocking the drivetrain at that level given your attitude towards it.

If you are worried about shift shock, smooth it out with the clutch. That's what it's for. Clutch wear is minimal when used this way, and replacing a clutch disc is much easier and cheaper than replacing other drivetrain components. Besides, shift shock from an un-rev-matched downshift is much more severe than a poorly rev-matched one, since no matter how badly you estimate the rev-match, the RPM difference is [should be] less than not rev-matching at all. If in doubt, smooth it out with some clutch slippage like I said above. And keep practicing those rev-matches. :)
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Re: More clutch paranoia: shift shock

Postby theholycow » Sat Apr 02, 2011 11:02 pm

Tups wrote:What's a shift shock?
Jerking from a rough shift (or even the minor tug of an acceptable shift).

six wrote:replacing a clutch disc is much easier and cheaper than replacing other drivetrain components.
Which drivetrain components are at risk from excessive shift shock? I imagine the CV joints and wheel bearings, both of which are way easier and cheaper than a clutch on a FWD car. Don't forget that most of the drivetrain is the same as a slushbox, which can have a very rough downshift when you suddenly floor it while cruising and it downshifts 2 or 3 gears...it's all designed for that kind of shock.

Anyway...
Besides, shift shock from an un-rev-matched downshift is much more severe than a poorly rev-matched one, since no matter how badly you estimate the rev-match, the RPM difference is [should be] less than not rev-matching at all. If in doubt, smooth it out with some clutch slippage like I said above. And keep practicing those rev-matches. :)
Agreed in entirety!

No need to be paranoid. You're aware of the potential issues and you won't be severely abusive. Drive how you want to and it'll probably be fine.
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Re: More clutch paranoia: shift shock

Postby LHOswald » Tue Apr 05, 2011 1:46 pm

theholycow wrote:Drive how you want to and it'll probably be fine.

that how i blew up my truck...
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Re: More clutch paranoia: shift shock

Postby theholycow » Tue Apr 05, 2011 1:49 pm

LHOswald wrote:
theholycow wrote:Drive how you want to and it'll probably be fine.

that how i blew up my truck...

Don't drive how LHOswald wants. :lol:
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Re: More clutch paranoia: shift shock

Postby watkins » Wed Apr 06, 2011 10:18 pm

Shame, Osballs. Shame!
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Re: More clutch paranoia: shift shock

Postby LHOswald » Fri Apr 08, 2011 11:47 am

listen, when your first vehicle is 5-speed and cost $500 and im paying $200 a month just to insure the f*cking thing...you get the idea.
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Re: More clutch paranoia: shift shock

Postby theholycow » Fri Apr 08, 2011 2:22 pm

$200/mo insurance on a $500 vehicle is reason to drive slower, not faster...the last thing you need is a ticket or a blown up truck.
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Re: More clutch paranoia: shift shock

Postby LHOswald » Fri Apr 08, 2011 3:38 pm

never got a ticket, did get a blown up truck though >.<
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Re: More clutch paranoia: shift shock

Postby Charles421 » Sun Apr 10, 2011 10:30 am

I found it very useful to learn rev-matching on downshifts, especially if you're traveling towards a red light that suddenly turns green. If I'm at ~35 MPH when that happens, for example, I get off the brake, clutch in, shift to 2nd, blip the accelerator to reach ~2.7-2.8k RPM and clutch out when it gets to ~2.5k quickly. No shift shock at all. By doing this I am in the ideal position to take the turn.
The whole downshifting process takes me 2-2.5 seconds, some people can do it a lot faster than that with practice (esp. w/ heel-toe. The method I described IS heel-toe without the brake part ;)).

Take some time on a straight empty road and learn to blip the accelerator. Get up to 40 MPH or whatever you're comfortable with, shift to neutral, then put your toes/balls of your foot on the accelerator pedal and give it a push. Don't be shy about the push.

Once you are fairly confident you can blip it and hit a target RPM (say, 3k), start experimenting with letting the clutch out to catch the next gear down. Know the RPM your car will be at in the gear you want to shift to. Pick one downshift to start and work on it exclusively - I started with 4>3. If I'm traveling in 4th at 2.2k RPM, I know I have to blip past 3k and let the clutch out at 2.9K to catch 3rd smoothly.

If anything, to start with blip it a bit further than you have to - don't be shy like I said. If you blip it a few hundred RPM higher than necessary, at least you have a good chance of catching the downshift at the right RPM. If you give it too little gas, you're guaranteed to have shift shock because the transmission is moving faster than the engine.

After a while you won't be looking at the tach anymore, you'll just know exactly how much pressure to apply and when to clutch out based on muscle memory. It's not something that's learned in a day.
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