Clutch pedal bump stop

[Meds]

I think the act of fully depressing (to the stop) eliminates any guesswork of where the pedal is in relation to the clutch.
When it's hard down on the stop, it's disengaged, no question.
Regardless, if more or less effort is needed to press the pedal.

I need to head out and try to change my habit (of a lifetime) to NOT fully depress the clutch pedal to the hard stop.

I'm thinking out loud here:
If I'm holding the peddle in the 'dead area' during the time it takes me to physically shift gear. Could a large undulation/bump/change in direction result in my foot/leg angle being altered, during the time it's taken me to shift the gear.
The result is the peddle moving while shifting = bad things happen.
Pressing the peddle to stop, eliminates this.

The act of pressing against the stop during the shift, removes this risk of the clutch engaging, mid-shift. Does it not?

But like I say, I need to head out and try it.

 

[futureZ4buyer]

So if I understood correctly, some people are switching gears without pushing the clutch fully?
Just asking because I've never heard of that.

 

[Meds]

So if I understood correctly, some people are switching gears without pushing the clutch fully?
Just asking because I've never heard of that.

Yes, seems so.
Some are 'floating' the pedal in thin air while changing or maneuvering with the clutch.
I guess this also means they have the pedal floating while starting the engine, rather than against the stop. Sounds bonkers to me.

I've tried this recently and find it inaccurate and I feel there's a high risk of crunching gears if your foot moves between shifts. Using the bump stop eliminates this risk.

I don't have confidence in the pedal if I cannot start its travel from the bulkhead hard stop.

At least with the pedal at full travel, on the bump stop, there's no risk, the clutch is disengaged when on the stop.

Maybe I'm still doing it wrong, but after 25years of driving like this and trying recently to change the habit, it's not happening.
I've tried many times since this conversation started.

I guess there's 2 different ways to use the clutch, based on what people have described.
1. Use the pedal bump stop on each press.
2. Float the pedal between the bite point and bump stop.

I'm firmly in option 1, despite trying option 2 a few times recently as I'm always open to new ideas.

Back on topic, though.
My home-made bump stop is perfect, my short ass stumpy legs are now not over extending to press the clutch to the stop. The 25mm less travel makes all the difference.
No more twisting hips or clicky knee joints.

 

[enuff_zed]

So if I understood correctly, some people are switching gears without pushing the clutch fully?
Just asking because I've never heard of that.

The disengagement point of the clutch is well before the pedal bottoms out.
Remember being taught to drive? Let the pedal come up until you feel the clutch bite. That is the point where the clutch disengages on the way down.

 

[Mr Tidy]

I just use the full travel when I depress the clutch pedal as I assume BMW gave it that amount of travel for a reason!

I pretty much have to in my 330i anyway or it won't start. :lol:

 

[futureZ4buyer]

I understand. Interesting. I never had that problem with any car, but I have long legs

 

[BMWZ4MC]

I’m fairly long of leg (6’ tall, 33-34” inside leg), so have no problem achieving full excursion of the clutch pedal. I tried a clutch stop a few years ago to see if reducing the pedal travel to little more than that required for the clutch to disengage would speed up my gear shifts on track. However, the clutch in my Zed disengages in the last third of the pedal travel, relatively close to the bulkhead, so the clutch stop prevented the clutch from fully disengaging.
The bite point of my clutch hasn’t changed in the last 90k miles ago, so I don’t think it’s indicative that the clutch is worn.
Regarding clutch pedal technique, I floor the pedal to the bulkhead when starting the car and during very fast, aggressive gear changes, but I tend to float the pedal just below the bite point when manoeuvring or in very slow moving traffic.
Holding the pedal off the floor requires much more muscular effort and finer control than simply pushing it against the hard stop of the bulkhead. The former requires synergistic contraction of quadriceps and hamstrings, and is highly dependent on neuromuscular feed back for precise control. There’s a significant risk of position drift with fatigue. The latter simply requires sustained contraction of the knee extensors against the immovable object that is the bulkhead with minimal finesse or control.

 

[futureZ4buyer]

Yeah, I figured that it might be different for every car. I won't experiment with this one. I understand the benefits but it is not worth it in my opinion.

 

[Wozzich]

Here's my 2 cents / experience / what I did. (Might be useful)
The reason i wanted one was because I'm 1930mm tall (6'4) and I have the sports seats. The seat is all the way back and down, I would prefer if it went down another 20-30mm but that's a much larger project. My knees are quite bent upwards so prefer the seat base tilted upwards at the front for support. But I found that with the full throw of the stock clutch stop there was a big mismatch between my right and left leg position.

Because getting anything out to Western Australia is slow and expensive (The UUC Big Boy is about $100au landed), I made my own.

I tried an M10 bolt, but found it was actually 3/8th (A little South Carolina in my German car). My local hardware store had these table feet. I needed to cut down the thread by about 20mm and then added a stick on pad to the bottom.

Cost about $7au and one hour of my time.
So far perfect.