Heavy shift knob

[FRSstyle]

So there are lots of advice to not rest your hand on the shifter in a manual because the pressure of your hand magnifies the pressure on the gears/synchros leading to wear and tear.

Would a heavier shift knob (over 1 pound) magnify this? People install heavier shift knobs to get a faster and smother shift feel, but I'm concerned about the heavier shift knob putting extra wear and tear on the gears/synchros.

[theholycow]

Your hand and arm weigh a whole lot more than 1 pound.

The knob might make that difference with this shifter:


Not so much with this one:


I'm a bit skeptical about the resting thing. IMO, if you're resting it such that the weight is straight down into the pivot, not pulling or pushing it against the transmission, you're fine in the same way your foot hovering a millimeter above the clutch pedal is fine but resting the weight of your leg on it is NOT fine.

[tankinbeans]

I personally rest my had on the console by the e-brake, but not for purposes of doing e-brake turns. It's just a more natural way for me to go about doing things.

That first shifter (Civic Si) seems gawky and difficult to use.

[theholycow]

Agreed, but people who have them insist that they're comfortable and natural.

[Squint]

Just on the principle that I will probably exert pressure I didn't mean to or was aware I was doing, I like to keep my hand off of the shifter unless actively changing something.

I don't remember who said the advice, it could have been cow, but I still remember: treat the clutch pedal and the shifter like they are lava when learning - don't touch them unless you have to do so.

That sets up decent habits in the long run of not accidentally putting pressure on either since your habit is to not touch either of them.

[mtheis]

I don't remember who said the advice, it could have been cow, but I still remember: treat the clutch pedal and the shifter like they are lava when learning - don't touch them unless you have to do so.

Fickset

[FRSstyle]

Your hand and arm weigh a whole lot more than 1 pound.


I'm a bit skeptical about the resting thing. IMO, if you're resting it such that the weight is straight down into the pivot, not pulling or pushing it against the transmission, you're fine in the same way your foot hovering a millimeter above the clutch pedal is fine but resting the weight of your leg on it is NOT fine.

I don't really rest my hand on the shifter. I actually just hold onto it like I'm holding a baby's hand, which is less than a pound of force. But the 1.6 pound shift knob would magnify my movements.



I'm also a bit skeptical about the resting thing. People have been resting their hands on the shifter for ages and I haven't really heard anything bad happen, but the advice is out there.

[Rope-Pusher]

Resting your hand isn't necessarily the problem. Same goes for heavy knobs. The problem can occur if you are imparting motion or force to the shift knob in the direction of shifting into or out of a gear range. The shift fork pads ride in a groove in the synchro sleeve and it's meant to be a floating contact except for during shifting, otherwise, as the synchro hub spins around, there will be wear of the hub, the fork pads, or both. When this happens, it adds freeplay to the shift action.

[Squint]

Could someone label that picture for those of us not lucky enough to take apart transmissions regularly?

[Rope-Pusher]

Could someone label that picture for those of us not lucky enough to take apart transmissions regularly?

No.

[watkins]

Shift fork.

[Rope-Pusher]

So the picture below is a shift fork, mounted on a metal bar called a shift rail.


The picture below is a Synchro Sleeve.


The picture below shows how the sleeve and the shift fork interact inside the transmission case.


See that each rail is attached to one shift fork. That shift fork interacts with one synchro sleeve.
That synchro sleeve interacts with a pair of speed range gears, like maybe 1st and 2nd, 3rd and 4th, or 5th and 6th.


(yes, some transmissions don't have pairs of speed range gears associated with each synchro sleeve. A common example of this is for 5th gear on a 5-speed gearbox.)

When you shift, the end result is that one of the shift rails is pushed or pulled such that one of the forks moves a synchro sleeve and through the miracle of digital electronics, a gear is engaged. There is an interlock that keep two rails from sliding at once, because if a two speed range gears were engaged at the same time, the transmission would lock up and not spin until something creative happened.

In a dual-clutch transmission, the speed range gear pairings are two odd gears, or two even gears, like 1st and 3rd as one pair and 2nd and 4th as another pair. Seems likely that, unless it was an 8-speed dual-clutch trans, there would also be some unpaired gears like on a 5-speed. Dual clutches are automated transmissions that can have two gears engaged at once, but with one of the clutches engaged and the other clutch disengaged, there is no lock-up.

[watkins]

Shift shafts!

[Rope-Pusher]

Shift shafts!

The wildwood flower grew wild on the farm
And we never knowed what it was called
Some say they's a flower and some say they's a weed
I didn't gave it much thought...

[watkins]

I spent the last two days in training tearing down every manual Chrysler has used in the past several years. I have seen far too many shift shafts.