Planet 9

Let me clarify .... usually do the hand on the gear shift knob when in city and stop and go traffic when have to shift a lot .... on the highway or when doing "serious driving," then both hands on the wheel.

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Jerry
2010 Boxster
Former Porsches: 1968 912, 1973 914, 1979 924
Engines: rear to mid to front and now heading back with mid

hear hear...

I believe the main issue is that the engine/tranny vibration is decoupled from the shifter. With a mechanical rod linkage your hand is actually fighting the vibration of the tranny all the time, which causes the forks to be moved slightly, which wears it. Obviously you aren't trying to fight the vibration, but your hand just being there applies a resistance, which is equivalent to a stationary engine with your hand wiggling back and forth (equal and opposite and whatnot).

With a cable linkage you can just sit your hand on the knob and it doesn't do anything to the transmission - still hand, still forks. Also most cables have a tiny bit of slack so any microscopic movement is not actuating the forks.

Well, I hadn't thought of that, since I haven't had a car with a shifter that shook in my memory. I actually think you have a point, that a shaking shifter might make the situation worse.

I also agree that if the forces from your hand are purely vertical or left-right, I don't see how damage can occur.

My understanding of the issue is that the gap between the shift fork and the synchro sleeve is so small (for the purpose of giving us positive and immediate shift feel) that almost any pressure towards the direction of the next shift closes the gap and wears the synchro. Since normal acceleration and braking causes g-forces to be exerted on you and car all the time (except, perhaps, when cruising on the highway) there's an excellent chance you are actually inadvertently pulling or pushing on the shifter. It shouldn't matter if the linkage is cabled or with rods, because if you have great shift feel you have very little play, and the effect of your hand pressure is the same.

Nonetheless, I admit I can't prove that any of this actually makes a difference in wear over a reasonable use period (like 100K miles), so I suppose I must concede that it's just one of those things that might not matter all that much, and only matters to the most obsessive of us.

(BTW, someone mentioned shift stops, and those are there to prevent bent forks, which are a different problem.)

Why do people feel the need to preach safety to others? So many threads turn into this. It gets old.

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John

Been a while since I've been inside a tranny, but the hand on the shifter causing synchro wear isn't true. The shifter is connected to a shift fork by some device (rod or cable). The shift rod rides in a groove in the synchro body. Moving the shifter first moves the shift fork into contact with one side of the groove, then continued pressure and movement of the shifter makes the synchro body move. The synchro body doesn't just sit there loosely, it is held in place by spring-loaded detents whether in or out of gear, and it takes a bit of effort to overcome the detents. In short, it won't move without some real pressure on it. Resting your hand on the shifter might cause the shift fork to contact the groove, but that's it. No synchro wear, maybe a couple microns worth of wear on the fork or groove.

Other than that, yes, both hands on the wheel, but in those quiet, relaxed moments when you rest your hand on the shifter, you are doing no harm.

Gris

A disregard for safety by someone else imperils my life. That's why I speak out about it.

OK, here's how it can be damaging:

The synchros in a gear box bring the gear that you're going to shift into to the same speed as the gear you're in. This keeps the transmission from grinding when you shift to the new gear. There are rings that cause the new gear to spin at the right speed. It's mechanical... I'm going to say "it's a series of tubes, like the internets" and leave it at that, except to say that the rings involved in the spinning can wear out. If you regularly shift from 4th to 2nd to make a turn, like I do, you'll wear out your second gear synchro rings and you'll have to learn to double clutch before jamming into 2nd, like I did on my '74 tii. (both the wearing out and the double clutching).

When you rest your hand on the shifter, if you don't move the lever at all, it probably won't do anything, but as the car hits bumps, goes around curves etc. It's pretty difficult to never move the shifter while resting your hand on it. When you move the shifter with the clutch out, it absolutely activates the synchro rings and that puts wear on them. Making a habit of it can do some damage eventually.

So, technically and theoretically, it's a bad idea. In practice, it's usually not the cause of a severe problem. Doing the 4 to 2 downshift a lot, like I do, is probably harder on synchros and definitely harder on the 2nd gear synchro.

I find double-clutching the Cayman still a bit awkward compared to a BMW. I'm working on some things.

The absolute worst bad driving habits are:

Driving with the left foot on the brake and dragging it slightly...This overheats the brakes and the light dragging glazes the surface of them and they don't work well. MPG suffers from, well, from dragging the brakes. The brake lights drive people nuts behind you and can create a safety hazard if you really have to stop (Crying wolf?)

Holding the car on a hill by keeping the clutch half in or rocking the car up and down an incline slowly by moving the clutch different amounts of halfway in.

The clutch pressure pad is made with brake pad material. When the clutch is out, this pad is pressing against a metal clutch plate. This connects the transmission output to the rear wheels. through the drive shaft and differential. It works just like a brake holding the car on a hill without wheels turning...it's a solid mass with the metal...no slipping...so no wear.

If the clutch pedal is all the way in, the pressure pad material does not touch the metal of the clutch plate, so there is also no wear in this position (except as mentioned wear to the throw-out bearing...another story, well told above).

It's necessary to slip the clutch pressure pad against the clutch plate a little to start off, but you want to get done with this and then leave the clutch all the way out or push it in...anything in between is generally bad for the clutch. Same deal as the brakes, slip the clutch too long and you'll get it very hot and you'll glaze the surface of the pad material and it won't feel right. Do this often and you'll be replacing the clutch often. This also explains why it's a bad idea to use really high RPMs for standing starts. Fun, but rough on the clutch. I know, if you do it just so.... But if you don't, you can use the clutch in a Porsche a very long time..

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-Sixisenuff
'06CS;ArcticSilver/Blk;PASM;SC;StuffedBose;NAV;GT2 seats;Udrive;PScooler;Mantissump;TTPOilsafe;Heigor ollbar;SchrothHrns;DMCHrnsbar;TPCswaybars;SpdARTca tbck;Dmptrncs;SftrncsPlenm&4.1flsh;18"PSS/ChampionRG5;18"PirWntr/BxterS;18"NT-01/Forgestar

Because they just won't listen.

I tend to avoid this as resting you hand on the shifter will inevitably lead to some laterial pressures working on the shifter which can't be good for the precision mechanics.

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CS 2007, Basalt Black

" we are sorry sir but po will not warranty your trans....we found abuse..telltale wear marks on your shifter...you have resting your hand on the shifter" ninja pleeezzz

Why are we even having this discussion? Both hands on the wheel - at all times unless you're shifting, then immediately back to the wheel. Dividing your time between casual and "serious driving" is dumb. Anytime you're behind the wheel you better be serious or you need to get off the road.

Indeed the most bizarre thread ever....

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Porsche Cayman DE1:http://youtu.be/KnEMv1Q5JKg

A while back there was a thread about the difference between a MT and the PDK. One person, who evidently drove a MT, asked with a PDK, where does your right hand go. There was a call on Cartalk about the damage a hand on the gear shift could cause problems. The question was this true for Porsches.

What perhaps is bizarre, is the number of responses all basically saying to keep both hands on the wheel.

Yes .... when on highway or on "winding roads" where really driving, not only is both hands on the wheel needed, but probably not listening to a radio, having a conversation with a passenger, talking on a phone even with a bluetooth connection, and no looking at a GPS to check a route. But on side streets when going slow or just for a leisurely drive in the country and stop and go driving, then if still need both hands on the wheel, then the other distractions should apply.

Given the number of threads about the radio and Porsche phone set-up without the expensive option and the number of cars which come with upgraded radios, people must be listening to the radio and talking on the phone when the car is moving.

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Jerry
2010 Boxster
Former Porsches: 1968 912, 1973 914, 1979 924
Engines: rear to mid to front and now heading back with mid

Then you should write a book about it and have it published. Adults do not need to be perpetually reminded to keep their hands on the wheel, put their seat belt on, look over their shoulder when backing up, not talk on the phone, etc.

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John

I also prefer to NOT be preached to about what is safe and unsafe driving. I already know and I still often times in urban traffic keep my hand on the gear shift lever. The reason....because in an urban environment one needs to shift every few hundred feet sometimes and even more often in others. Redlights every block or two, stop signs where there are no red lights, turning cars in front of you every block.......try putting both hands on the wheel during those times and it's just not going to work for even those of you who preach. And I often drive in urban areas for hours at a time. The thread had nothing to do with bad driving habits like cell phones, music or any other distraction. But when I deem it necessary to keep my hand on the gear shift, is any damage resulting? I suggest the answer is no because anyone in the transmission business I've talked to and a few knowlegable people here have said no damage is occuring and my experience tells me they are correct. I've been driving MT with a console shifter of one brand or another for 50 years and never once in those 50 years have I had any problems related to keeping ones hand on the shifter. Not once in almost a million miles I've driven. And I've not heard any other opinions that have been substantiated by experts to change my opinion.

Me too ... for little over 50 years have had a MT car and for many of those 50 plus years, it was a sports car, and I too have at times keep my hand on the gear shift without any problems, and that is why when Click and Clack said it was bad, I asked. I too now feel it is not a problem regarding the transmission.

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Jerry
2010 Boxster
Former Porsches: 1968 912, 1973 914, 1979 924
Engines: rear to mid to front and now heading back with mid

I put a hand on the gearshift sometimes.

Got to switch between "D" and "M" once in a while. *ducks*

I definently messed up the synchros on my Fiat 124 when I was in college by resting my hand on the shifter...paying for a new transmission cured me of this evil. Another very different point is that I shattered my wrist in a crash (not my fault) I was not resting on the shifter but had my hand on it in the middle of a down shift when an idiot made a left turn right in front of me...T boned him at 30...my wrist was jammed on the shifter...lessons learned the hard way...now I am always quick on and off the shifter...the habit is great practice for track days.

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JCO CST

On track, I will occasionally quickly reach down to the shifter just to confirm the gear I am in. I've had an instructor smack me for doing that. Yep, it's both hands on the wheel!

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'08 CS - Meteor Gray, Cocoa, Sport Mode, PASM, Short Shift, Sport Seats, Sport Steering Wheel, GT-3 brake ducts, Bi-Xenon, and a few other goodies.
'90 944 S2 - India Red, Black/Linen

I love these cars!!!