What is the effect of NOT rev matching on downshifts on synchros. I understand they will wear more quickly but wouldnt they last a considerable amount of time perhaps 100k miles. I honestly never heard of this when learning to drive a stick. Not sure if poor instruction or I just didnt pay attention.
Rev matching on downshifts
- Thread starter raaizin
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I think that has to do with synchronized transmissions like in a heavy duty big rig. You HAVE to match rpm to downshift or wait until rpms drop.
Never heard of it in a car.
Honda motorcycles have synced transmissions but can shift without throttle.
Never heard of it in a car.
Honda motorcycles have synced transmissions but can shift without throttle.
Not matching leads to jerky behavior--the trans might not care much, but you'll "shock" the car when the engine has to suddenly change when the clutch is let out quickly. If you let the clutch out slowly, you might not notice, the engine just matches, and IMO the clutch wear might be minimal (it'd be none if the rev matching was done properly). Honestly, the more I've driven a car, the more I've just naturally "known" when to let the clutch out and have a smooth driving experience--I learn how to burp the motor to get the match.
For the sycro's to not take wear, you'd have to double-clutch and rev match while in neutral, so as to get the mainshaft at the proper speed. Maybe this matters if you plan to go over 300k on the clock. Having take a couple of stickshifts to 200k I'm pretty sure double clutching isn't needed for such low mile vehicles.
Of course, someone is going to come along now and point out, you'll save wear on an expensive clutch and transmission by not downshifting when coming to a stop, brakes are cheaper, that sort of thing. They have a point, but what's the fun in that?
For the sycro's to not take wear, you'd have to double-clutch and rev match while in neutral, so as to get the mainshaft at the proper speed. Maybe this matters if you plan to go over 300k on the clock. Having take a couple of stickshifts to 200k I'm pretty sure double clutching isn't needed for such low mile vehicles.
Of course, someone is going to come along now and point out, you'll save wear on an expensive clutch and transmission by not downshifting when coming to a stop, brakes are cheaper, that sort of thing. They have a point, but what's the fun in that?
Most experienced stick drivers rev match on a downshift without thought even if they've never heard the term before.
The big truck transmission I learned on was a 10 speed Road Ranger. If you tried to use the clutch between gears or missed a gear, you had to come to a complete stop to get it back in gear. Once rolling from a stop, it was only synced shifting and never with the clutch. Yeah, you don't even think about it after about the first 10,000 shifts.
Harsher downshifts and a bit more clutch wear can be added into the mix as well.
It's mostly just to downshift more smoothly, which can be essential on a track while cornering, so you don't throw the balance off of the car.
Also when passing, its nice to rev match the downshift so you are smoothly accelerating right away.
Watch some videos on how to do it, its part of the fun of driving a manual.
Also when passing, its nice to rev match the downshift so you are smoothly accelerating right away.
Watch some videos on how to do it, its part of the fun of driving a manual.
Me either. 2013 Ford Focus 5 spd. Bought new/still own @ 125K. Trans smooth as butter. 2000 VW Jetta 5 spd. Bought new/sold @ 220K owned 14 years. Trans fine. No rev match downshifts. To me this is a performance driving technique to reduce jerking in turns downshifting which can break traction. I rarely do this but it does smooth things out.
Won't hurt the transmission at all, but as mentioned above there will be a slight amount of additional wear on the clutch, but same as if you over rev matched. My Integra has a computer controlled rev match option (it can be turned off) and it does smooth the shifts out.
Rev matching is only necessary if you're skipping gears or entering a gear after coasting in neutral.
Rev matching is only necessary if you're skipping gears or entering a gear after coasting in neutral.
Plus is sounds cool.
...and eliminates the drama when entering a corner whilst at the same time scrubbing speed.
On cars, it's more wear on the sychronizers, which are usually made out of brass, along with less wear on the clutch. When you start grinding when you shift, and forced to double clutch, that's when you know the synchros are worn.
Once you get good at it rev matching with your car, it becomes second nature, and you do it in normal driving.
My last Passat, I bought a short shifter, but never installed it, because, I sync'd the rowing of the gears with how the engine speeds up or down between shifts. Got rid of the car at 220k miles with the original clutch.
Once you know the relationship of gear and speed, when you drive hard on the back roads, and need to downshift to around the "recommended speed" for that turn, you'll shift to the appropriate gear, rev match it, and get back onto the power after the apex, and it's more satisfying when you do it correctly.
Once you get good at it rev matching with your car, it becomes second nature, and you do it in normal driving.
My last Passat, I bought a short shifter, but never installed it, because, I sync'd the rowing of the gears with how the engine speeds up or down between shifts. Got rid of the car at 220k miles with the original clutch.
Once you know the relationship of gear and speed, when you drive hard on the back roads, and need to downshift to around the "recommended speed" for that turn, you'll shift to the appropriate gear, rev match it, and get back onto the power after the apex, and it's more satisfying when you do it correctly.
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Race car drivers rev match downshift because it upsets the suspension on a harsh downshift and can make you lose control, and it makes you several tenths of a second faster around a track.
Also, race transmissions are usually straight cut with dog rings. They are not synchronized.
A synchro on a street car transmission will outlive the car.
Also, race transmissions are usually straight cut with dog rings. They are not synchronized.
A synchro on a street car transmission will outlive the car.
Every manual trans I've had I rev match. I don't even think about it.
Oh yeah, plus you can say "I rev match bro" in convos with your friends that drive autos to flex on them. I hardly downshift normally driving. When approaching lights, I just brake until RPMs drop off to the point of pushign the clutch in and putting it in second to be ready for a green. If I was in a car with someone rev match downshifting to every slow down/light I'd ask them what was wrong with them
. Add heel toe for even more manual guy street cred.
I'm the best manual driver you ever seen
LOL Imagine someone shifting up 1-2-3-4-5-6 and then down 6-5-4-3-2-1 at every traffic light. That's too much work! Wouldn't you need about a half-mile to stop?
The only cars I hear rev matching the downshifts and grabbing EVERY lower gear when stopping at a streetlight, are the ones with 8" coffee can exhaust or neighbor hater pipes.
Ricers only use first and second gears in town, everyone knows this.
Talking to some manual afficionados...this is what you should do complete with heel-toe.
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