Is skipping gears on a downshift naughty?

[EvilSardine]

I spent a good amount of time searching the forum about this but the only "skipping gears" posts I have found are about up shifting. I have found other results on the internet but I haven't come across people stating facts. I have only found people's opinions on this specific topic, which is something I'm not looking for.

Every car manufacturer's transmissions are different so what's fine on one might not be on our Si's.

Sometimes, I'm cruising along in 6th gear on the highway and while getting on the offramp I double clutch and rev match my down shift into 4th for a perfectly smooth shift. I might even go into 3rd if I need to. All of these shifts are always rev matched.

Is it fine on our transmissions to skip gears like this? I don't skip gears on an up shift, though.

I'm not sure if the synchros are going through any pain while doing this, especially if the revs were matched perfectly using double clutching.

The reason I ask is that I just watched a Mugen RR video where the driver down shifted into 2nd from 5th but stopped at every gear in between. It always seemed like it was fine to skip gears, but then watching this video made me want to make sure.


Please don't post if you're just assuming what the answer is. Assuming is bad. =)

Thanks in advance!

[vince1128]

i wont assume, but i do wanna hear the answer.

[glockaxis]

Sounds fine to me especially that you mention double clutch and rev-matching.

[ErichPryde]

why would skipping gears actually cause a problem? assuming that you're not downshifting into a gear while you are at too high of a speed for that gear to accept, there won't be a problem.

your transmission is made to shift. there's over a hundred years of building experience in that transmission, and even though it does have some issues with third gear, it was STILL made pretty well.


As long as your engine speed essentially matches the rate at which the gear you are shifting into is spinning, you should not have any issues.

[rob76]

It does put more strain on the synchros if you don't double clutch.
Does the guy in the video double clutch as well as hit every gear? That sounds redundant.

[scubastevect64]

As long as when skipping those gears, you don't downshift into RED!

[Gr3y Goose]

should be ok as long as you just dont go into gear and come off the clutch without matching...if you want just go through the gears for a better piece of mind.

[ErichPryde]

Originally Posted by Gr3y Goose

should be ok as long as you just dont go into gear and come off the clutch without matching...if you want just go through the gears for a better piece of mind.

I'm wondering how the guy in the RR did it. did he do it very quickly? sometimes I do this when I'm driving quickly and I'm not sure what gear I am going to end up in/need.

[rob76]

I know that one way to test the synchros is to shift without the clutch. when you shift from say 1st into 2nd you just pop it out of first and put some pressure towards 2nd, when the rev's drop to the right point it will just slip right it. You can also downshift this way by blipping the throttle up higher than the rev-matching point and then pushing the shifter towards the gear you want it will just slip in at the right rpm. If your synchros are bad you'd have a hard time doing this. So I think even though you're rev matching there is still something the synchros have to do in order to get into gear smoothly. Double clutching brings some internal spindle/gear up to the right speed and makes the synchro unnecessary. So in short, double clutching definately spares the synchros since they arn't even needed when you're double clutching.

[rob76]

If you don't rev match it's also hard on the clutch and drivetrain. It's a lot of force to dump on it all suddenly.

[0720Steve]

it depends, plain and simple.

[mrbill]

Originally Posted by Honda Service News January 2006

Skip Shifting Is Brutal on Synchronizers [emphasis mine]

Gear ratios in 6-speed manual trannies are spaced close together so you can keep the engine speed in its optimum range for max power and acceleration. Shifting to the next higher or lower gear in a close-ratio tranny causes small changes in engine speed.

Shifting a close-ratio tranny through its gears by the numbers puts a very small load on the synchronizers since they only have to make small changes to the speed of the mainshaft and the clutch disc.

Some drivers, though, like to skip shift so they don’t have to work the clutch pedal and shift lever as much. They like to accelerate in 1st gear, then pop it into 3rd gear, then into 5th or 6th. Skip shifting, though, is really brutal on synchronizers; [emphasis mine] it puts a higher demand on them than they were designed to take. Skip shifting can cause premature synchronizer wear that can cause the gears to grind when you shift up or down. [emphasis mine]

If you’ve got a vehicle in your shop for repeated damage to the synchronizers, go for a test-drive with your service customer to see if he or she is guilty of skip shifting. If that’s the case, remind him or her skip shifting can be an expensive habit to break.

-mr. bill

[EvilSardine]

That says nothing about rev matching using double clutching when skipping them though.

I never skip gears while shifting up and I never skip gears while shifting down without double clutching.

I can imagine it being super harsh on your synchros if you were to drop down from 6th to 3rd without even rev matching.

[mrbill]

No, it doesn't say anything about double clutching to perfection.

Your manufacturer says don't skip shift. You're on your own.

(You wanted fact, not opinion. Opinion? You shouldn't lose sleep with your perfect double clutch downshifts.)

-mr. bill

[EvilSardine]

Originally Posted by mrbill

Your manufacturer says don't skip shift.

Yes, they do. Most likely they say this because they're thinking about Bobby who's not rev matching. I'm pretty sure most of the problems they have seen are from the many people out there who go from 6th gear down to 3rd without even thinking about matching revs. Or those that red line 3rd and go directly to 6th without even waiting for the revs to drop.

Originally Posted by mrbill

You shouldn't lose sleep with your perfect double clutch downshifts.

Yeah, I'm probably worrying about it too much. I don't track my car at all and I don't treat my transmission like garbage so I'm pretty sure if I keep doing what I'm doing it'll last a long time.

Thanks for the help so far guys.

[rob76]

I think what you want to do is this: at 60mph in 6th push the clutch in, pop into neutral, let the clutch out, rev it up to 6000, push the clutch in, put into 3rd, let the clutch out and get on the gas at the same time. I think that will spin the internals up and put no extra load on the 3rd gear synchro. make sense?

If you were to double clutch but not rev it up to 6000 until after you depressed the clutch for the second time I think it would still put a large strain on the synchro because then it would be spinning at a much different rate than the output shaft when you do rev it up to 6000.

[rob76]

I just found this, it explains it even more.
Double Clutchings & Synchros

[shutter13]

if you're revmatching skipping gears is fine.... alot easier on your components than rowing down through the gears to get to your desired one!

[andy22]

the Mr Bill article is for up shifting not down shifting. Isn't there a mechanical difference?

[jdecker]

Every time i;m on the interstate if i need to pass somebody i just drop to either 4th or 3rd (depending on how fast im going) rev match, pass, and up shift. I don't bother with that double clutch crap, that was more for old cars, with shitty or no synchros. It doesn't matter enough nowadays to be significant.