RPM Matching when Shifting

[leathermaneod]

Hey all,

I have a couple questions about shifting. My truck (maybe most vehicles? I've experienced this with other manual vehicles), is hard to get into 2nd when I'm rolling too fast, about 10-15 mph. Too fast to get into 2nd, too slow to use 3rd. Anyway, I recently finally discovered that if I bring the RPMs up, it will go in, not as nicely as normal, but a lot easier. Maybe I just need the RPMs higher still? Is this normal? Normal for a trans with 260k anyway lol. Also, when shifting, I have always gently released the skinny pedal while gently pressing in the clutch to avoid letting off the throttle too abruptly, and avoid the jolt you get if you press the clutch all the way in too quick. Then I select a gear and begin matching the RPMs as I let the clutch out. Should I be matching the RPMs before I select a gear to be easier on things? How do you all shift? Kind of a silly question I know, but I'm wondering how all you more experienced guys shift these trucks.

Thank you!

Edited September 14, 2016 by leathermaneod

[CSM]

It burns out the syncros shifting that way.  

[leathermaneod]

Which? The way I'm shifting now? Or rpm matching?

[TFaoro]

I use the clutch, but I also try to get my rpms in the right area. Makes shifting with a dual disc clutch easier, and is easier on the syncros. 

 

Don't shift without the clutch. It's not good for the 4500.

[leathermaneod]

I don't shift without the clutch, I'm just saying I don't rpm match. Just put the clutch in, shift to neutral, shift to gear. Then bring rpms up as I'm letting the clutch out. Would I be less hard on my trans if I do bring the rpms up before putting in gear from neutral? 

[TFaoro]

2 minutes ago, leathermaneod said:

I don't shift without the clutch, I'm just saying I don't rpm match. Just put the clutch in, shift to neutral, shift to gear. Then bring rpms up as I'm letting the clutch out. Would I be less hard on my trans if I do bring the rpms up before putting in gear from neutral? 

It will be easier on the clutch and on the trans. 

1. You're not dragging the clutch backwards as it brings the rpms back up.

2. You aren't making the syncros fight the speed of the clutch as much if you bring it to the right rpm. 

 

Shifting to the next gear, say 4-5 I just don't let the rpms fall all the way off. Let em drop 500rpm or so then drop it in the next gear. Don't let them fall to idle. 

 

Shifting down, I hit the throttle to bring rpms up.

[CSM]

8 minutes ago, leathermaneod said:

I don't shift without the clutch, I'm just saying I don't rpm match. Just put the clutch in, shift to neutral, shift to gear. Then bring rpms up as I'm letting the clutch out. Would I be less hard on my trans if I do bring the rpms up before putting in gear from neutral? 

im sorry. I misread.  I thought you ment you were shifting without the clutch entirely.  Carry on!

[Haggar]

The closer you match the engine RPM to the selected new gear RPM at the speed you are attempting is better for the transmission.    

 

This could be speeding the engine up A LOT in a downshift situation or picking the engine speed up a little (from idle) for an upshift. 

 

HTH 

 

Hag

[leathermaneod]

ok let me just make sure I understand correctly. When getting ready to shift, you release the go pedal all the way as you press the clutch, then you just press it again to slightly bring rpms up before selecting the gear? Isn't it harder on the clutch material having it at higher rpms as its being engaged(slipping more)?

35 minutes ago, TFaoro said:

It will be easier on the clutch and on the trans. 

1. You're not dragging the clutch backwards as it brings the rpms back up.

2. You aren't making the syncros fight the speed of the clutch as much if you bring it to the right rpm. 

 

Shifting to the next gear, say 4-5 I just don't let the rpms fall all the way off. Let em drop 500rpm or so then drop it in the next gear. Don't let them fall to idle. 

 

Shifting down, I hit the throttle to bring rpms up.

So do you not fully release the accelerator even as you push the clutch in?

Sorry for all the dump questions lol I just got thinking about this and wondered if I've been driving a manual wrong(or not the best) all these years. 

 

I understand about bringing them up on a downshift, especially if it doesnt wanna go in the gear you want. guess I was never taught, or never realized you should try to match them on an upshift....

Edited September 14, 2016 by leathermaneod

[dripley]

As said when up shifting Dont let the rpm fall of to much. I try and get to the next gear at the same time the rpm drops to match it. My tranny shifts a little slower sometimes with the SB clutch so when that happens I just bump the throttle slightly and slip in gear. When down shifting I bump the throttle a little harder to get the rpm up to match the lower gear. It is more of a feel than actually looking at the tach and going for a specific rpm. That just comes from driving a stick most of my life. 

[Haggar]

Wow, I started on a small encyclopedia and gave up...

 

Clutch wear is increased at LARGER differentials of speed between the engine and what the last speed the clutch was turning.

SMALLER differentials of speed have reduced clutch wear.

Let that sink in.

 

It has nothing to do with total speeds (within reason but we are talking stock stuff at the moment.)    If you floor your truck at a stop and slowly let the clutch out, that is much more wear than leaving the truck at idle and slowly letting the clutch out. (assuming the TIME it took to let it out was about the same.)

 

If you were running 55mph in 4th gear at 1800 rpms, and put it in neutral, (assuming on a slight down hill so you maintain 55) then later push the clutch back in, reved the engine to 1800  re-selected 4th and let the clutch back out, that would be perfect.  Synchros matched AND almost zero wear to the clutch.  (since 1800rpm was almost exactly the right speed for what the transmission was being spun by the rear wheels.  So there was ZERO differential speed, but 1800rpm actual speed)

 

oh i hope this makes sense...

 

Hag 

[leathermaneod]

Ok so I tried this on my way back to work.  Not quite as hard as I expected, but a little tricky since the throttle is so touchy. I was basically keeping my foot on the throttle when pressing the clutch, just easing up a bit and trying not to let the rpms fall all the way. Is that correct or should I be letting all the way off, then bring it back up from idle before selecting a gear? Or does it not matter? This all just seems a little like extra slipping of the clutch.....

I shift very slow to try and take it easy on the trans, so I can't make it to the next gear before the rpms drop to idle.... almost make it two seperate movements, one to neutral, one to the next gear. 

I feel like such a noob like I'm asking you guys to teach me to drive stick over the internet lol I've been doing it for the last 7 years since I started driving, but never really gave a lot of thought to exactly how I was doing it. Always did it as I described in my earlier posts. Then again two of those were smaller transmissions in a ford escort and a ford ranger. Only one was bigger like this truck and that was in my 7.3 idi ford. 

Yes that makes perfect sense @Haggar. Thank you!

29 minutes ago, dripley said:

As said when up shifting Dont let the rpm fall of to much. I try and get to the next gear at the same time the rpm drops to match it. My tranny shifts a little slower sometimes with the SB clutch so when that happens I just bump the throttle slightly and slip in gear. When down shifting I bump the throttle a little harder to get the rpm up to match the lower gear. It is more of a feel than actually looking at the tach and going for a specific rpm. That just comes from driving a stick most of my life. 

So you do let off the throttle all the way, then bump to bring back up? 

[Haggar]

Keep playing with it.  You don't want it to "flare" as you push the clutch in.  (engine speed up)  You are correct that "flare" would be more clutch wear. 

 

I guess I am starting to lift off the go pedal as i am pushing the clutch in.  Not enough that I feel engine braking (letting off the go while still in gear) but as close as I can get.  

 

My shifting is slow too, so I will basically blip the throttle once or twice keeping the rpms up but to too much as i catch the next gear. 

 

Down shifting under load is a lot harder for me,  I get it exactly right only about 25% of the time on our hills.  but that takes braking in lets say 4th gear until a speed that will be good for 3rd gear at 2200 rpm or so, then pushing in the clutch bringing the rpm up to 2200, selecting 3rd,  then letting the clutch out pretty quick....  since I am then speeding up rolling down the hill..... and both feet are occupied...  I usually get a little jerk (clutch heat and wear) or engine trying to head for the red line (speed increased too fast between gears and load pushing like a rocket...)  

 

Keep in mind, we are just trying to be perfect.  It sounds like your normal shifting is so close to good enough that you couldn't measure the wear difference.  Speed matching will make shifting smoother and reduce wear that little bit more.  

 

Hag

[leathermaneod]

Thank you very much @Haggar, this is all very helpful! Still just a little unclear on wether I should be letting all the way off when I press the clutch and then coming back up with the rpms, or just keeping them up without flaring? Or does it not matter at that point? 

Again, thank you!

[sooxies]

Lots of good info on here....glad to have read through.  I've only been driving a standard shift since 2012 so even I'm still learning as I always will be.  Don't ever lug the truck either...any automobile for a matter of fact.    

[dripley]

When I up shift I depress the clutch and let off the throttle completely. I do shift quicker than you, meaning i dont pause in neutral. Sometimes the tranny does not cooperate and it pauses in neutral, usually when my clutch foot is lazy and I dont depress it to the floor. When that happens just a little blip on the the throttle will keep the rpm enough to closely match. Like @Haggar I too sometimes have to do twice.

[TFaoro]

4 hours ago, leathermaneod said:

So do you not fully release the accelerator even as you push the clutch in?

It all depends on how fast you shift I guess. I depress clutch completely while letting off the throttle completely, pop it out of gear, then as the rpms drop into the right range slide it into gear and step back on the throttle to keep those rpms the same until the clutch is fully released. 

4 hours ago, leathermaneod said:

I understand about bringing them up on a downshift, especially if it doesnt wanna go in the gear you want. guess I was never taught, or never realized you should try to match them on an upshift.

You definitely don't have to, it just causes less wear on the syncros and clutch. 

[leathermaneod]

Well thank you all very much for all the great info! I have to echo what @sooxies said about continuing to learn about this! I guess what @dripley and @Haggar are doing most of the time, or on upshifts at least, is more of just a blip to get the rpms close, then dropping into gear(correct me if I'm wrong). For some reason I took it as trying to match with the tac as closely as possible, then dropping in, which is a bit tricky, at least for me at this point. That said, when I get it right, and keep them in the right range as I drop it in and let the clutch out, its very smooth...guess I just need to get better at it :-) my goal will be to get in the habbit of holding the rpms steady as I select the gear and release the clutch. Do you know, will it hurt the clutch to never fully release the throttle? Basically just ease up to let rpms down where you want them while pressing in the clutch, then select the gear and release the clutch?

[TFaoro]

2 minutes ago, leathermaneod said:

Do you know, will it hurt the clutch to never fully release the throttle? Basically just ease up to let rpms down where you want them while pressing in the clutch, then select the gear and release the clutch?

Nope, it's better for the disc and surfaces to do that. You won't hurt it. 

[leathermaneod]

1 minute ago, TFaoro said:

Nope, it's better for the disc and surfaces to do that. You won't hurt it. 

Thanks! Buy you said you don't do that(maybe I misunderstood)? Is there particular reason you don't?