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Why rev match? Downshifting query

Discussion in 'New Riders and Riding Tips' started by agelow, May 22, 2011.

  1. Hi guys

    I've noticed lately that when I am slowing down, I would rev match and go down to 5th, but after that, i hold in the clutch and just tap all the way down to 1st.

    I just roll into stop, and release clutch when the revs are really low.

    Sometimes I go into neutral and im still rolling so i can release clutch.

    Is this a bad habit? Should I be rev matching ALL the way down? Does this affect fuel economy/clutch wear?

    Thanks guys!
  2. bad for too many reasons to mention.
  3. Google "compression lock up"
  4. Can we get a proper answer for this one please? im really interested too.

    I personally rev match all the way down through the gears as i do when driving my diesel patrol.
  5. excessive/un-needed strain on gearbox/clutch/sprockets/chain/rider/etc...

    Compression lockup will f.duck you up if you cause one at the wrong time.

    funny enough, if you google "What is compression lock up motorcycle" you get this


    in the first 5 or so
  6. You need to be in the correct gear at all times, so you should go down through the gears sequentially.
    You rev match to reduce the chances of locking up the rear tyre, AND it helps the drivetrain mechanically. You are also failing to utilize your engine braking.

    If you go all the way to first still doing 40kph and the lights change, meaning you need to ride on, you are in the wrong gear completely.

    Your technique is poor, and dangerous to you, even for those with slipper clutches when riding around suburbia....so stop doing what you are doing. Do some searching on this site for the correct way to ride your bike, if you don't know. Not having a go at you...just discontinue riding that way....it really is bad.

    Fuel economy? Who cares! If you rode your bike properly, you would'nt be wearing out your brakes quite as much.
    Clutch? Who cares! Ride the correct way and forget about it. It's inconsequential.
  7. Why does no one think of the furry little kittens. :(
  8. been riding a harley street bob with go fast mods all weekend
    if you dont rev match that biatch will kick its arse out so fast ( its all torque ) and next thing you know your on your ass

    hence why harley riders always rev the bike changing down gears to stop at lights etc
  9. Compression lock up on harleys must be a biatch, they're still revving in neutral when stopped at the lights. And just about everywhere else, too.
  10. If I'm riding at all quickly, or enjoying myself at all, I rev match. If I'm just dawdling along because I need to get home, I often just click down with the clutch held in, but I'm still careful to know exactly what gear I'm in and make sure it's the right one for the conditions and speed. That is, I don't just knock down five gears in two seconds at the same speed. Gear-changes can baulk or fail if there is no speed difference between the motor and the gearbox, but a small speed difference is optimal. If there's a large mismatch, there will be a bang, not a click. That isn't good for your gearbox.

    As a learner or beginner, I'd suggest that you change down each gear in turn, release the clutch, then make the next change using rev matching, all the way down to 1st and stop. I'm a lazy old man. Do as I say, not as I do.
  11. If you are coasting i neutral towards a light... what do you do if you notice somebody about to slam into you from behind and you're doing say... about 40kph?

    • Kick her into 1t and you're libel to get a compression lockup - car hit you (at best whilst you're upright, at worst after you drop the bike due to the locked back wheel).
    • Try to kick it into a higher gear to avoid the compression lock - valuable time wasted that would be best served getting out of the way of the car in the first place.

    I can think of at least two situations over recent months when I would have been in trouble if I coasted up to a light in neutral...
    1. Damp road and coming up to a red - car behind me wasn't paying attention and locked his brakes when he finally noticed. I accelerated through the red to avoid a rear-ending.
    2. Another red (on Windsor Rd), again a car who was obviously fixated on "beating the lights" accelerated as I was stopping. Noticed him and quickly jumped into the adjoining lane and he shot through the red.

    Both of above scenarios could have ended in tears if I'd been coasting in neutral and the valuable time selecting a gear was required. Do remember though that if you are engine-braking you should squeeze the front brake just enough to trigger your stop light. Some cagers don't seem to notice you're slowing down without the aid of the bright red light.
  12. a little off topic, but a compression lock-up can be used as a fairly advanced technique to turn the bike at corner entry. only really good for when you are riding with a bit of pace though.
  13. Maybe so Jimmy but its a good thing for novices and newbies to know about - it was never explained to me on any course I did and the first time it happened to me on the R1 i was lucky not to come unstuck
  14. Agelow, why do you want to coast to a stop holding the clutch in the whole way? What's the advantage? Why did you start doing that?
  15. Thanks guys for replies. Been very helpful for myself as a newbie.

    Rob - started doing it because I found I couldn't co-ordinate my hands to rev match all the way down fast enough before I needed to stop. So usually I'd be stuck at 3 and completely stopped.

    So started just rolling in and tapping all the way down which seemed easier. I didnt know it was bad technique/dangerous.

    Will have to practice rev-matching more.

    When I'm more confident Ill rock up to saturday practices
  16. Agelow, are you talking about "blipping" in an uncoordinated way??

    If yes, hold of.

    When you have the clutch in and the new gear selected, you can dial up any revs you want with the throttle then slowly release the clutch. There's no panic involved. Did the bike leap ahead (to many revs), lurch and slow down violently (not enough revs) or decellerate gently (good rev secetion) or maintain speed (revs dead on right for that speed/gear combo).

    Do that for a while until you get the hang of it and after a while the time it takes to get the revs right will reduce.
  17. Agelow, I know you posted in the mentor thread seeking some one on one help but it got a bit buried because you ended up in conversations there, Maybe time to post another request to bring it back up to the top again. Sorry I am not in your area or I ouwld try to assist.

    You could also try posting in the Saturday proactice thread to see if there is anyone out your way who would be happy to excort you into practice and home again.
  18. Agelow

    Lets get back to your original post that described, how you choose to decelerate. You rev match to 5th, then hold the clutch in as you tap down the box to a stop? I'm assuming that you hold the clutch in and slow using the brakes, coast down with the clutch in as you change and as speed reduces - and then finally drop into first?

    In order to understand this question properly and give you an answer that will be useful, could you clarify what you mean by "rev match"? Why you may ask? OK, so long as you time each downshift to the speed loss and the rolling speed of the bike rather than just banging rapidly through the gears at speed you'll do no damage, and releasing the clutch will be fine so long as the rolling speed you do it at matches the speed range of the gear. The chances of compression lock in this circumstance are remote.

    However if the speed is wrong and the gear doesn't match by being too low for the speed you're travelling at then it's possible, but only if you release the clutch to engage the rear wheel sufficiently for the rate of engine deceleration to overcome the friction of the tyre on the road.

    Do you need to rev match? the simple answer is of course, and you may have done exactly this in your car. I've seen many people go from 5th to 2nd for example using the H gate of a car and so long as the speed is reduced sufficiently by the time they let the clutch out, no problem. This is in fact called 'block shifting' and in some circunstances entirely OK so long as you know what you're doing. I do it myself when I think its appropriate.

    Some people myself included, slow gradually and 'blip' the throttle a tiny bit as the clutch comes in and the gear change is made. This is actually a throw back to olden days of clutches being run in vegetable based oils but we like doing it cos it sounds good and it certainly helps on big clunky old twins like my GS. This has the advantage of firstly aiding the clutch in separating by suddenly spinning the engine and more importantly allows matching the revs to the gear and deceleration more smoothly by feathering the clutch as it engages the engine.

    As for using the engine to slow you down between gear changes, of course you can, but as a general rule, the brakes are for slowing and the gears are for going. The important issue here is WHY are you doing what you do? Once you know the answer to that we can provide an intelligent answer.

    Therefore, is it because you feel unnerved during deceleration? Has something happened to cause this or is it just a kind of laziness? Do you leave your slowing too late and then feel compelled to bang through the gears simply because you don't have time to change, release the clutch, change and repeat?

    Ideally, slowing down under normal circumstances is carried out with plenty of time through good planning. My wife achieves perfect down changes by holding the clutch in on the approach to traffic lights and by changing down gradually without blipping. Simply matching rolling speed to gear selection.

    My advice is get yourself to a large, safe and deserted area and practice both block changing and blip changing. You'll find that both can be useful and you'll become more acquainted to your bike. Good luck.
  19. Have to admit, I suck at rev matching on the bike, I'm working on it, I'm a clumsy b****** but I'll get there. My learning experience with compression lock up was in a Mazda RX-8 on a damp race track on a corner that I was well and truly committed to.

    I really don't want to have to deal with that on a bike so I'm working on rev matching.

    When I was very green, and when not appropriate to practice I just work my way down through the gears (no coasting with the clutch held in or in neutral) and don't ride the bike in a way that it is likely to suffer from compression lock up.

    The though of coasting along with functionally no drive makes me shudder.
  20. Biggest mistake I see is people blipping as soon as the pull the clutch. The motor revs and the dies then they disengage the clutch and you get a double varoom. GAY.
    Or revving too much and surging.
    It should be one nice sound. So if you have a sports bike that revs up and down quickly you need to blip just before disengaging the clutch.
    If your on a big cc tourer or cruiser that has a big heavy crank then you have more time to let the clutch out. Because it winds down slowly.