Rev matching: opinions?

[EFI]

Well, there's really no need to rev match at these small speed differences when the aim is to slow down, at least on the bike, and the engine does not have to do much to catch up either. That's why I find it a bit annoying that the car tries to do the rev matching when I'm slowing down like this.

If you're trying to slow down, rev matching is 100% needed. Higher engine speeds means more engine braking thus more slowing down. It's also doing this to save the clutch and the transmission...to just let it it catch up (regardless how little) is bad on the entire drivetrain especially the clutch. Brakes are cheaper and easier to replace than a clutch.

This may have worked on a 400lb bike, it's a whole different story on a 4000lb car. Sounds like it's easy to disable though which is good for you but bad for your clutch.

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[Michael_vroomvroom]

I really, really, REALLY can't understand using that technique on a bike, where your balance is also involved. There's just no need to increase the risks involved like that; basically you've just let yourself learn a crappy technique. I used to ride (still carry the 'M' endorsement on my driver's license).

Other than for getting underway from a full stop, slipping the clutch like that is needless and just plain wrong.

With all due respect, that is just your opinion. Go to a motorcycle racing track and you will find plenty of people slipping the clutch. You may think you know what they do is "plain wrong", but I'll bet many of them have a lot more experience riding fast than either you or me, so I would not be so absolute in my opinion regarding what is wrong and what is right and what is crappy technique and what is good technique. Google around a bit and you will find several articles discussing the pros and cons of slipping the clutch (both on the track and on the road) versus rev-matching and relying on the breaks. Once you've gotten used to it and know your bike, it feels as safe as anything else on the bike.

Of course, if your basis is that using the engine for slowing is inherently wrong, even on a bike, then everything stops there.

When the speed differences are not huge, you may not need to be downshifting at all. Don't be afraid to use the brakes to lose small amounts of speed, just brushing them works just fine. Either that or don't wait so late to downshift that you then need more braking than is natural for the lower gear that you selected.

Thanks, but I'm not afraid to use the breaks a little bit. If it's just to slow down a bit for a few seconds, then return to previous speed, brakes are preferred. I downshift when it looks like I'm going to be going slower for a while, so a lower gear is more suited, or when I'm planing to stop. Once you're used to this technique, it's both easier and faster.

 

[Norm Peterson]

With all due respect, that is just your opinion. Go to a motorcycle racing track and you will find plenty of people slipping the clutch. You may think you know what they do is "plain wrong", but I'll bet many of them have a lot more experience riding fast than either you or me, so I would not be so absolute in my opinion regarding what is wrong and what is right and what is crappy technique and what is good technique. Google around a bit and you will find several articles discussing the pros and cons of slipping the clutch (both on the track and on the road) versus rev-matching and relying on the breaks.

How about you provide me with a link. Just don't try to fool me with links to discussions involving drum-braked bikes or cars, where the brakes truly were inadequate and did need all the help you could find for them.

I do understand a few things about tire grip, slip%, and slip angles. Enough to know that sudden changes in individual tire traction requirements are never good, and that nobody can guarantee that every time they try to "gradualize" their clutch re-engagement that they're going to be sufficiently gradual about it. Sometimes, poo happens, and this kind of poo can certainly be avoided in any street driving even if you insist on taking the extra risk on the track.

Once you've gotten used to it and know your bike, it feels as safe as anything else on the bike.

There's still going to be the time when your timing with the clutch lever isn't as smooth as it should be. Do you really need that in your life when there's a way that's inherently better?

Of course, if your basis is that using the engine for slowing is inherently wrong, even on a bike, then everything stops there.

I have nothing against using engine compression braking. As long as you're only counting on the amount of deceleration you get from any given gear without using car or bike momentum to drag the engine rpms up against compression and rotational inertia. With, again, an exception for partial or complete service brake failure.

Thanks, but I'm not afraid to use the breaks a little bit. If it's just to slow down a bit for a few seconds, then return to previous speed, brakes are preferred. I downshift when it looks like I'm going to be going slower for a while, so a lower gear is more suited, or when I'm planing to stop. Once you're used to this technique, it's both easier and faster.

Sounds like laziness to me, where you'd rather involve only your left hand and left foot, vs both hands and both feet for a proper downshift. And you've apparently carried that over to your car driving.

I still remember my riding days, where with a smallbore Kawasaki I normally would downshift at least twice while slowing from cruising speed to a stop. Clutch lever, shifter, brake lever, and foot brake all - not a physical hardship at all, and I never needed any brief increase in engine braking through needlessly harsh clutch re-engagement.


Norm

 

[Michael_vroomvroom]

How about you provide me with a link. Just don't try to fool me with links to discussions involving drum-braked bikes or cars, where the brakes truly were inadequate and did need all the help you could find for them.

Here's an article about riding at slow speed on the road and regulating the speed by slipping the clutch:
https://www.ridelikeapro.com/motormans-articles/stop-using-rear-brake/


Here's one that discusses the same for the track:
https://lifeatlean.com/motorcycle-downshifting-technique/

I do understand a few things about tire grip, slip%, and slip angles. Enough to know that sudden changes in individual tire traction requirements are never good, and that nobody can guarantee that every time they try to "gradualize" their clutch re-engagement that they're going to be sufficiently gradual about it. Sometimes, poo happens, and this kind of poo can certainly be avoided in any street driving even if you insist on taking the extra risk on the track.

There's still going to be the time when your timing with the clutch lever isn't as smooth as it should be. Do you really need that in your life when there's a way that's inherently better?

I don't think "blipping the throttle" is inherently better in the cases I've mentioned. That's just your opinion.

Whatever "sudden changes in individual tire traction requirements" are to occur, they would also apply when relying on the brakes to slow down, so I'm afraid I don't see your point here.

Sounds like laziness to me, where you'd rather involve only your left hand and left foot, vs both hands and both feet for a proper downshift. And you've apparently carried that over to your car driving.

Not carried over quite yet, thank you very much. My previous cars were as said older low performance "family-type" cars, and the ones that were manual I drove like you seem to suggest. It was immediately obvious they were nothing like my sportsbikes, so it just seemed natural to drive them like you suggest. Just a boring drive in a boring car to get from A to B in whatever way is easiest on the car, going by the mantra it's a lot cheaper to wear out the brakes than other parts of the powertrain.


Mustang (or any performance car for that matter) is a brand new experience for me and I'm going to use some time figuring out how to drive it well. In the summer I'd love to take Ford performance's two-day driving school where they use their own Mustangs if I can afford it. Don't suppose anyone reading this has done that, but if so, I'd sure love to hear their opinion of it.

 

[Coosawjack]

I love it and it works both up and down shifting........wondered if I could "rev-match shift" without the clutch........NOPE......clutch must be depressed for it to work!!

 

[WD Pro]

I love it and it works both up and down shifting........wondered if I could "rev-match shift" without the clutch........NOPE......clutch must be depressed for it to work!!

As in it allows full throttle shifts ? i.e. you can keep the throttle floored and the engine won’t bounce on the limiter when the clutch is pressed ? (I’d try it, but mines not built yet ... lol)

WD

 

[Pero]

As in it allows full throttle shifts ?

Yes, it allows "no lift" shifts.
You can keep throttle unchanged and the engine won't rev up for some time to let you engage next shift.
But I don't feel relaxed with this routine. I'm manual shift driver for more than 30 years, from my first kilometer till present day, and one of the basic rules, I have learned, is "clutch in - throttle out".
I can't get rid of this reflex reaction.

 

[Norm Peterson]

I love it and it works both up and down shifting........wondered if I could "rev-match shift" without the clutch........NOPE......clutch must be depressed for it to work!!

But you can rev-match a downshift without touching the clutch if ARM is not present (and probably with a car that has ARM if it's been turned off). This means you have to do all of the rev-matching yourself and the throttle blip is absolutely, 100% required. That's not something you should be doing very often, but it is a good skill to have in your gearshifting toolbox.


Norm

 

[Norm Peterson]

Here's an article about riding at slow speed on the road and regulating the speed by slipping the clutch:
https://www.ridelikeapro.com/motormans-articles/stop-using-rear-brake/


Here's one that discusses the same for the track:
https://lifeatlean.com/motorcycle-downshifting-technique/

I'll have to spend a little more time with those . . . but the street-oriented one seems to be talking about using clutch slippage to manage power delivery. Not rear wheel braking coming from engine compression. The second one clearly notes

This slowing down of the rear wheel means it will more than likely break traction with the road, after which you will experience something like rear tyre skipping or slewing from side to side. This in turn can compromise your corner entry control.

which agrees with what I've been saying all along.

I'll have to look into the matter of slipper clutches, though those have no relevance for the S550 Mustang.

I don't think "blipping the throttle" is inherently better in the cases I've mentioned. That's just your opinion.

Whatever "sudden changes in individual tire traction requirements" are to occur, they would also apply when relying on the brakes to slow down, so I'm afraid I don't see your point here.

Not just my opinion, FWIW, suddenly adding new traction requirements when you're already operating out close to the friction ellipse is far more likely to bring on unpleasant consequences than suddenly initiating the braking or cornering maneuver that first puts you out near the ellipse.

Not carried over quite yet, thank you very much. My previous cars were as said older low performance "family-type" cars, and the ones that were manual I drove like you seem to suggest. It was immediately obvious they were nothing like my sportsbikes, so it just seemed natural to drive them like you suggest. Just a boring drive in a boring car to get from A to B in whatever way is easiest on the car, going by the mantra it's a lot cheaper to wear out the brakes than other parts of the powertrain.

Spoiler alert . . . that technique works equally well (if not better) in an exciting car driven in exciting fashion. The poo that could happen in that exciting car is sufficiently more serious and more likely that there's no point in introducing needless risk. Cars aren't like the kinds of bikes where rear braking is completely independent of front braking where you could back off the rear braking a tad while dragging the engine revs up.

Mustang (or any performance car for that matter) is a brand new experience for me and I'm going to use some time figuring out how to drive it well. In the summer I'd love to take Ford performance's two-day driving school where they use their own Mustangs if I can afford it. Don't suppose anyone reading this has done that, but if so, I'd sure love to hear their opinion of it.

My suggestion for now - focus on being smooth. That doesn't mean your control actions should be slow or drawn-out.


Norm

 

[peoples1234]

@Michael_vroomvroom

Most people who ride on the track (which I am not a pro by any means, just mid-pack intermediate) use the clutch at the start of the session and at the end of the session (a bit hyperbolic unless they have a quick shifter, but the point remains) and most track bikes have slipper clutches--which your car does not.

On a bike, you use the clutch to modulate slow-speed maneuvers. I'm not convinced that anything you do on a bike should really translate to the car, with the exception of the release of the clutch to start from a stop. Not trying to give you a hard time, but if you are using downshifting to slow the car down any appreciable amount by dragging the clutch--you're doing it wrong.

 

[doccoch]

love not having to heel-toe and messing up my nice shoes

 

[ireminisce]

First off, welcome to the club. Hope other than rev match, you're enjoying your stang! Nice to see another super sport rider in here as well, I have an 07 Kawsaki ZX-10R SE and a 15 Kawasaki ZX-10R ABS.

With that said, I just got my GT 2 months ago and it took me a while to get used to the rev matching but I absolutely love it now. I've only ever had manual shift mustangs, outside from my very first car which was a ford escort and an inbetween car which was a mistake (Infiniti G37). You really appreciate it when spirited driving or track driving (which I am getting ready to do with this stang soon). It really does rev match near perfectly for that. For engine braking it is great as well but I will drop the exhaust in Normal or Quiet mode if I am stuck in traffic and don't want my engine revving everytime I drop a gear. But I can also get away by just no dropping a gear and using the brakes, engine only rev matches as soon as you tap the shfiter in the direction of the gear you're going in.
I'm sure you've figured it out by now (havent read the other 3 pages of this thread) but you can turn it off and do away with it. I actually felt it made all of my shifting feel more seamless considering the clutch releases much later than my 12 GT did.

 

[Norm Peterson]

Mustang (or any performance car for that matter) is a brand new experience for me and I'm going to use some time figuring out how to drive it well. In the summer I'd love to take Ford performance's two-day driving school where they use their own Mustangs if I can afford it. Don't suppose anyone reading this has done that, but if so, I'd sure love to hear their opinion of it.

A couple of things occurred to me in the wee small hours this morning (one of the less desirable aspects of aging).

First is that the majority of motorcycle clutches are wet clutches. Which means that you have the oil medium to take heat out of the clutch discs and transfer it to the transmission case and from there off the bike entirely. Car clutches are 'dry', and can only reject heat into air, which has nowhere near the thermal characteristics of gear oil to either remove heat from the clutch or transfer it into the bellhousing.

Second, even wet clutches are not free from having problems in automotive applications. Chevy's 8-speed automatic, like virtually all automatic transmissions these days, features a lockup torque converter. Which makes it a wet clutch. The thing you need to focus on comes next - that particular transmission has been fraught with shudder problems. Problems that the performance AT industry has traced to slip% tables in the control system (emphasized for its similarity to what you're at least sometimes doing with your engine braking). This transmission's lockup clutch was designed to slip (I think I heard by 5% - 15%), specifically to soften the shifts. Much the same as what you're doing manually, though GM was doing it more for driver/passenger comfort than for tire grip reasons. Not that the reason matters when it's a problem associated with clutch slip itself that we're talking about.

GM has TSB'd this problem with everything from triple fluid changes to outright torque converter replacement, apparently with no guaranteed fix to date. I think GM may have even modified their slip% tables, though not to the extent that the aftermarket has.

A racing bike is different from a street driven car in that lots more components are considered "consumables" than just tires, brake pads, and fluids. So beating up on a racing bike's clutch and having to replace/refresh it from time to time is to be expected there, where it would not be at all acceptable in a street driven car.


I saved the content of those links to Word files so I can look at them at a more leisurely pace than when researching solely for message board response purposes. Maybe I'll even print them out, because I find I learn better off a piece of paper than from a computer screen.


Norm

 

[shogun32]

Some do not use the brakes much at all, even on the track, but just downshift and slip the clutch before cornering, while others do the full "clutch in, rev match to a larger or smaller extent, downshift, clutch out, break, corner"

man, what kind of "little slow down" tracks do you frequent? Jarez? (has huge brakng zones)

Even on my pathetic GS500 I'm very heavy on the brakes for at least half a second if not longer before I even think about adjusting gears and shifting down for the correct gear to drive out. I've never heard of anyone trying to use engine braking to adjust speed in anything but minor amounts. And if you're doing that you might as well keep neutral throttle and feather the rear brake. Closing the throttle means chassis pitch, weight transfer, and change in contact patch which could easily land you on your ass if done injudiciously.

When you hear a bike engine being repeatedly dragged up to match road speed going thru the gears it's somebody who needs a lot more practice and a tutorial on the Reg Pridmore method.

 

[Michael_vroomvroom]

man, what kind of "little slow down" tracks do you frequent? Jarez? (has huge brakng zones)

Even on my pathetic GS500 I'm very heavy on the brakes for at least half a second if not longer before I even think about adjusting gears and shifting down for the correct gear to drive out. I've never heard of anyone trying to use engine braking to adjust speed in anything but minor amounts. And if you're doing that you might as well keep neutral throttle and feather the rear brake. Closing the throttle means chassis pitch, weight transfer, and change in contact patch which could easily land you on your ass if done injudiciously.

When you hear a bike engine being repeatedly dragged up to match road speed going thru the gears it's somebody who needs a lot more practice and a tutorial on the Reg Pridmore method.

Sounds like you're doing the opposite of what this guy, Josh Herrin (who is still racing as a pro in the superbike class it looks like), does then.

If you go to 7:26 in the video below,

,

you can see him describing what he does: going from full speed in sixth gear, then as soon as he's grabbing the brakes before the turn, as soon as he applies "just the littlest of pressures", he's immediately doing his downshifts. 5, 4, 3, 2.

Going from open throttle in sixth gear to second gear so quickly, I'm sure he is hitting the brakes hard too, and one can't tell from what he says in this video how much braking he's getting from the engine and how much from the brakes. However because he also says that what he does if it's raining is the opposite: grabbing the brakes and then waiting to downshift, in order to avoid locking up the rear tire and other problems, I think one can assume he engine braking quite a bit otherwise.

Of course, he also says a lot of other guys do the opposite; grab the brakes and then wait to downshift.

Also, while the GS500 is a nice bike I'm sure (I've not tried it, but I did ride a 400 Bandit for a full day's tour through the mountains of Thailand some fifteen years ago, and the GS500 looks very similar), I don't know if there is all that much carryover to sportsbikes.

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