Downshifting gears

[Chriswright03 1,257]

I have ridden with IAM riders who insist that youshouldn't see their brake light because they are not using their brakes and using gears instead.  When questioned as to what warning does that give to the motorist behind they are usually either lost for an answer or give an arrogant reply stating that is their problem and they should be taking more notice.

 

I took my Police Advanced course in the 80's and was taught to use the gearbox to make sure I was in the right gear at the right time.  That did no imply I use the gearbox to slow down but just to assess the road ahead and decide what gear to be in so that I could use the engine power to react.  I think if people are comfortable doing what they do and it works for them be it whichever way then great.  I think the OP will now have a good idea of how to carry on and in fact has replied to say he has appreciated the advice so job done really.

 

I agree with Steve Thackery in what he says in respect of if you know you are coming to a full stop you can wait until you have stopped and then block change.  I choose not to do it because that is my preference.  That isn't to say I never do it but I just prefer to be in second if I am coming to a stop say at lights as they have a habit of changing when you are on top of them. 

 

Just moving away from the topic for the moment and onto brakes.  I was always taught to use both brakes but come off the front brake once you are down to walking pace and then the forks settle at the front as the rear brake has sufficient power to stop you at that speed.  I always taught that to my pupils when I was instructing as it takes away the risk of locking the front brake on gravel when you stop and losing control.

 

Oh and yes I do still do the Hendon Shuffle although I realise there really is no need.

[neojynx 722]

I also took my Police advanced in the 80s.  The IAM riders who you mentioned , well Ill make no further comment.  There are times when you hit the rear brake just to activate the rear light as a warning without actually braking.  

[SteveThackery 3,090]

1 hour ago, Chriswright03 said:

I took my Police Advanced course in the 80's and was taught to use the gearbox to make sure I was in the right gear at the right time.  That did no imply I use the gearbox to slow down but just to assess the road ahead and decide what gear to be in so that I could use the engine power to react.

 

Exactly.  Spot on.

 

1 hour ago, Chriswright03 said:

I agree with Steve Thackery in what he says in respect of if you know you are coming to a full stop you can wait until you have stopped and then block change.

 

I'm honoured!  But just a tiny point to clarify: I don't wait until I'm at a full stop to block change, as most bike gearboxes won't co-operate when the bike is stopped.  Rather, I do a leisurely block change over the last few seconds of motion - maybe from 10-15mph downwards.  The clutch remains held in until I reach neutral.

[Jeffprince 4,921]

Someone mentioned double de-clutching above. As I remember from years back, that involved selecting neutral then letting the clutch out completely (in a car, that is) and upping the revs while still in neutral, then changing to the lower gear. I don't remember anything similar on bikes, and it's not possible to be in neutral other than from 2nd to first gear. 

Lots are mentioning blipping the throttle on downshifts....if gear selection is well matched to road speed, what's the point (other than posing or wasting fuel)?

Finally, RoadSmart's emphasis on riding in a lower gear than we'd normally select obviates the use of brakes far more. Having tried it, it works despite taking some getting used to.

[fred_jb 10,264]

11 minutes ago, Jeffprince said:

 

Lots are mentioning blipping the throttle on downshifts....if gear selection is well matched to road speed, what's the point (other than posing or wasting fuel)?

 

By definition the gear you are in is the only one in which engine speed is correctly matched to road speed. If you change down, either the engine speed has to increase or the road speed has to decrease, both almost instantaneously as the new ratio engages.

 

The latter can't happen, but can cause a momentary lock up of the rear tyre, though slipper clutches can minimise this effect.This leaves increasing engine speed as the best way to match the new ratio to the existing road speed, which is what the blip is accomplishing.

 

Edited April 23, 2019 by fred_jb

[Jeffprince 4,921]

5 minutes ago, fred_jb said:

By definition the gear you are in is the only one in which engine speed is correctly matched to road speed. 

Not in the case of using engine braking ....the point being that the engine speed is not matched to road speed if you have employed any engine braking. Use engine braking, then change down. No blip needed. I do accept the rear lock up issue, though.

(Sorry if I sound pedantic)

[fred_jb 10,264]

10 minutes ago, Jeffprince said:

Not in the case of using engine braking ....the point being that the engine speed is not matched to road speed if you have employed any engine braking. Use engine braking, then change down. No blip needed. I do accept the rear lock up issue, though.

(Sorry if I sound pedantic)

Sorry to disagree, but engine braking is immaterial.  You may be allowing the resistance of the motor to slow the bike but the road speed reduces as engine speed decreases, so the two remain locked into a fixed relationship determined by the gear ratio in use at the time.

 

As soon as you select a new ratio you disrupt the existing match between engine and road speed and this needs to be accomodated one way or another.

 

For downshifts, you either do it the jolty way by making the rear tyre and transmission enforce a correct new higher engine speed, or you do it the silky smooth way by blipping while the clutch is activated so that as the clutch is released the engine is spinning at the new faster speed needed to match the existing road speed.

 

Edited April 23, 2019 by fred_jb

[Jeffprince 4,921]

Fair point Fred. It's been so damn long since I've been on the bike (bloody arthritis) that I may have forgotten if I do blip or not. Interesting debate, though...

[fred_jb 10,264]

If you don't believe me think back to an occasion when you have accidentally engaged a lower gear in your car when intending to select a higher gear - surely we have all done that at least once!

 

The engine screams as it gets forced to spin faster and you get a massive jolt as the driven wheels and transmission force the engine to do so.

[fred_jb 10,264]

4 minutes ago, Jeffprince said:

Fair point Fred. It's been so damn long since I've been on the bike (bloody arthritis) that I may have forgotten if I do blip or not. Interesting debate, though...

Sorry to hear that Jeff, hopefully you will see some improvement with the warmer weather.

[Ciaran 6,880]

May I ask how one blips the throttle? Upon reading this thread last time I took the bike out I tried it and found myself always revving too high and getting a sort of see saw effect. I wonder if it’s because I generally ride at very low revs...

Edited April 23, 2019 by Ciaran1602

[sandalfarm 2,764]

Wasn't  there a fault in some motorbike gearbox that enabled you to shift from 5th to first and killed some people before the defect was discovered

[fred_jb 10,264]

13 minutes ago, Ciaran1602 said:

May I ask how one blips the throttle? Upon reading this thread last time I took the bike out I tried it and found myself always revving too high and getting a sort of see saw effect. I wonder if it’s because I generally rode at very low revs...

The way I think it works is that the blip as you operate the clutch and move the gear lever causes the revs to rise and then start to fall, and the trick is not to overdo it, and to time the release of the clutch to engage just when the revs are more or less correct, i.e. faster than before you started the downshift, but not massively faster.  It doesn't have to be exact because any small mismatch between revs and road speed will be absorbed by slippage of the clutch plates as the clutch engages.  You soon get a feel for the right revs for your particular bike and its gear ratios.

 

Edited April 23, 2019 by fred_jb

[Tex 36,816]

23 minutes ago, fred_jb said:

If you don't believe me think back to an occasion when you have accidentally engaged a lower gear in your car when intending to select a higher gear - surely we have all done that at least once!

 

The engine screams as it gets forced to spin faster and you get a massive jolt as the driven wheels and transmission force the engine to do so.

 

Mate of mine, racing a Trident at Brands, got his feet mixed up while on ‘full ‘ole at bottom bend and hooked it into second when he was expecting fourth.. two broken hands, one clavicle and some bruising that I have never seen the equal of.. 

[Tex 36,816]

2 minutes ago, sandalfarm said:

Wasn't  there a fault in some motorbike gearbox that enabled you to shift from 5th to first and killed some people before the defect was discovered

 

I think you’re referring to the ‘rotary shift’ boxes on some Japanese bikes (still fitted for certain markets, I understand). These went N-1-2-3-4-5-N-1... if you were in fifth but thought you had a higher gear left you could prod it into neutral and then (thinking you had missed the shift) prod it down to first. The very first Kawasaki 650 was like that.  

[Grumpy old man 4,670]

7 hours ago, Ciaran1602 said:

May I ask how one blips the throttle? Upon reading this thread last time I took the bike out I tried it and found myself always revving too high and getting a sort of see saw effect. I wonder if it’s because I generally ride at very low revs...

Is it because you have a DCT😉