Emergency braking: Clutch or de-clutch?

[Crasherfromwayback]

In an emergency ??? I definitely don't gently squeeze .. I stand on everything ..

Hahaha..most riders do mate. But if you squeeze them progressively harder you'll be amazed how hard you can squeeze them without locking the wheel. Grab a handful and normally you'll simply lock the wheel and hit the deck.

[george formby]

Hahaha..most riders do mate. But if you squeeze them progressively harder you'll be amazed how hard you can squeeze them without locking the wheel. Grab a handful and normally you'll simply lock the wheel and hit the deck.

I had a squirt on a Fireblade a wee while back & one of the first things I did was test the brakes, pretty much as you described. The distance from 100kmh to falling off in suprise was FA. Unlike my bike I could just keep on loading the front & it buried itself into the road, stopping in way less time than I expected.

[Crasherfromwayback]

I had a squirt on a Fireblade a wee while back & one of the first things I did was test the brakes, pretty much as you described. The distance from 100kmh to falling off in suprise was FA. Unlike my bike I could just keep on loading the front & it buried itself into the road, stopping in way less time than I expected.

Aye. Even in the wet you'd be amazed how hard you can squeeze 'em, if you're nice and progressive (smooth). It's sudden inputs of ANY type a bike doesn't like.

[The Stranger:Me]

I can tell you with the new riders we help that it often halves (yes, halves) their stopping distance by simply engaging the clutch immediately.

Engaging? really? so you recommend they don't pull in the clutch.

[Brett]

Disagree. Sports bike riders always like to brag about how big there balls are saying they don't need the rear brake because they brake so hard the back is off the ground. If you can manage an airborne rear tyre under braking then you should be able to manage a locked rear tyre. If your worried about what happens when you come off the rear brake, then DON'T!

In the context of an emergency upright maximum braking stop a locked rear wheel is not high on the list of priorities. If you're not upright you shouldn't be maximum braking. If you are and it locks leave it locked. IMHO & taught by prof instructors.

Not really about having big balls, nor is it really a bragging thing. Just noticed it with most sports bikes I have owned (with weight distribution being more forward of the C.O.G.) that when I really brake hard, be it on a race track slowing down for a hair pin or a quick stop on the road, my back wheel will only just touch the road. I have had the back wheel lift on occasion under a really hard stop (intentional stoppies excluded of course).
But agree, holding the back wheel in check while locked up is not really anything difficult nor special.

[awa355]

You are riding a big cruiser with most of the weight over the rear, a longer wheelbase etc. Less forward weight transfer?
How would you alter ( if at all) your emergency braking procedure over that of a high powered sportsbike?

I'm thinking of the usage of the rear brake here.

[Crasherfromwayback]

You are riding a big cruiser with most of the weight over the rear, a longer wheelbase etc. Less forward weight transfer?
How would you alter ( if at all) your emergency braking procedure over that of a high powered sportsbike?

I'm thinking of the usage of the rear brake here.

You can use (and get away with using) far more rear brake on a fat old cruiser. Still wanna use as much of the front as you can chuck at it though.

[The Stranger:Me]

You are riding a big cruiser with most of the weight over the rear, a longer wheelbase etc. Less forward weight transfer?
How would you alter ( if at all) your emergency braking procedure over that of a high powered sportsbike?

I'm thinking of the usage of the rear brake here.

Look at a sport bike or trailie under brakes. The bike tends to rotate around the front wheel as the front forks compress adding even more weight to the front.

On a big cruiser that effect is not so pronounced. Sure teh forks will compress and you still get more weight and stopping power from the front. But because the geometry and lower, more rearward center of gravity the bike isn't pressing the forks down. Instead its trying to push the front wheel out - i.e it locks easier.

By observation, when you get a front wheel lock on a cruiser it appears that there may even be a form of negative castor effect as they seem to wash out easier.
I say that because we frequently see sport bikes lock the front without any problem, yet invariably when we see a cruiser lock the front we see the bars go round and the bike go down.

So, in answer to your question. The rear is certainly important on a cruiser. The front is still more important. We suggest you focus on the front first get that working right then the rear. If you have 70% braking force on the front, you may as well take 100% of that first before you focus on the other 30.

[kiwi cowboy]

Break heard and gear down and let engine breaking help you out.

If the back wheel locks you will instantly know by the stopped engine an can let of the rear break to regain control.

If its not engage you will only know the rear is locked up when it starts coming around, you let go the rear break and the locked rear snatches traction and causes the bike to become unstable.

My 2c

ps. a slipper clutch is a great help here as it limits rear wheel torque.

I agree with this post and gearing down while braking should become automatic through practice as being in the right gear should you need instant power is as important imo.

[Okey Dokey]

Gosh, I really hestitate to post when both sides have been argued so well. I will say that, personally, I don't think it is a good thing to practice emergency braking pulling in the clutch as soon as the front brake is applied. Your right hand is not "wired" to your left one. They can act independently and you can practice and train them to do so.

It is good to encourage practice for all riders. I have locked up my rear practicing, and guess what, I didn't die, and learned to release it immediately and not to stomp on it next time. That is what practice is for.

Like others have said, I clutch right at the end of my braking to avoid stalling. Otherwise my focus is on the brake controls.

[Crasherfromwayback]

By observation, when you get a front wheel lock on a cruiser it appears that there may even be a form of negative castor effect as they seem to wash out easier.
I say that because we frequently see sport bikes lock the front without any problem, yet invariably when we see a cruiser lock the front we see the bars go round and the bike go down.

.

Not saying you're wrong...but I dunno about that. As a practice thing I used to do on my moto-x bikes at the beach, I used to ride for as long as I could with the front wheel locked on the juice. Simply to understand what the front end felt like locked, and to learn how to control it. I think it's easier to do that with a bike with more rake (as in dirt bike and cruiser) than a full on sports bike with a steep rake.

[kiwi cowboy]

Look at a sport bike or trailie under brakes. The bike tends to rotate around the front wheel as the front forks compress adding even more weight to the front.

On a big cruiser that effect is not so pronounced. Sure teh forks will compress and you still get more weight and stopping power from the front. But because the geometry and lower, more rearward center of gravity the bike isn't pressing the forks down. Instead its trying to push the front wheel out - i.e it locks easier.

By observation, when you get a front wheel lock on a cruiser it appears that there may even be a form of negative castor effect as they seem to wash out easier.
I say that because we frequently see sport bikes lock the front without any problem, yet invariably when we see a cruiser lock the front we see the bars go round and the bike go down.

So, in answer to your question. The rear is certainly important on a cruiser. The front is still more important. We suggest you focus on the front first get that working right then the rear. If you have 70% braking force on the front, you may as well take 100% of that first before you focus on the other 30.

Reguarding your last paragraph here mate i would have to dissagree on getting the front working on a cruiser first.
Just my opinion but when i owned my intruder i found under hard braking it was better to hit the rear a split second before the front as it seamed to have the effect of sucking the whole bike down then the rear and front worked in unisen but if the front was on first it diddnt compress the rear suspension and the rear diddnt have the same bite.
Might have just me but would be interested in other peoples views on this.

[Crasherfromwayback]

Reguarding your last paragraph here mate i would have to dissagree on getting the front working on a cruiser first.
Just my opinion but when i owned my intruder i found under hard braking it was better to hit the rear a split second before the front as it seamed to have the effect of sucking the whole bike down then the rear and front worked in unisen but if the front was on first it diddnt compress the rear suspension and the rear diddnt have the same bite.
Might have just me but would be interested in other peoples views on this.

To a certain extent, they say this'll work on full on race bikes as well. I think it's a valid point of view on cruisers, but not so on sports bikes. I tend to think when hard out on the front picks on a sports bike, the rear only settles it a little and stops it swinging round and trying to overtake the front wheel. Right up to the point that the rear wheel is off the deck.

[kiwi cowboy]

To a certain extent, they say this'll work on full on race bikes as well. I think it's a valid point of view on cruisers, but not so on sports bikes. I tend to think when hard out on the front picks on a sports bike, the rear only settles it a little and stops it swinging round and trying to overtake the front wheel. Right up to the point that the rear wheel is off the deck.

I dont try it on my race bike- i only ment it for cruisers.
My race bike gets the front hard progressivly and yes the first few times on the track it amazed me how hard you could actually get on it and the back only a little bit at the same time changing down.
I do use the rear sometimes mid corner or on a double apex corner to settle the bike which works quite well but im getting off topic sorry.

[CookMySock]

To suggest that practising emergency braking is pointless (is that what you are suggesting - not sure) because it doesn't work out in some scenarios is not a good reason to give up on learning how to do it.

Well, no, but laboratory conditions are not where it matters. Perhaps you CAN save a few meters braking with the clutch in, but when the shit hits the fan perhaps your attention is better focused on other things.

Because the rear wheel takes longer to slow down (and lock) when it is being driven by the engine. Even if you don't lock the rear wheel, you still don't want to be driving it using the engine during an emergency braking session. [....] I guess I have watched a lot of people practising emergency braking, and have observed the impact it makes when pulling in the clutch.

I agree with you, but I submit that closing the throttle is enough. Later in the evasive manoevre I agree that either the clutch will have to come in, or a downchange selected, but normally at least 50% of your speed and 99% of the problem is gone by then.

To me, emergency braking is bringing a motorcycle to a stop in the minimum distance. [....] Emergency braking is about responding to something that you didn't expect. Something you didn't plan.

You see, these are two different things. I can pull my bike up in the shortest possible distance as a technical demonstration, but in the real world things are not so cut-and-dried.

Ie, it is easy to make some scientific demonstration, but out in the wild there are too many variables. An important thing to remember is, at open road speeds it is very likely indeed that you physically do not have the stopping distance required. A new plan must be hatched in the blink of an eye, and that may amount to standing the bike up for 1.2second and belting the brakes really hard, then to 25% brake and scrape a footpeg one side, swerve hard over to the opposite side braking very hard indeed for the 0.5second the bike is upright, releasing to 25% as you scrape the opposite footpeg. With such actions set in motion your technical demonstration (while correct in a straight line) is largely obsoleted by more pressing demands.

That blink of an eye is all you get, and you don't want to be futzing with the irrelevant or overtly subscribing to some laboratory ideal, or else you are going to taste 4WD bumper today.

I don't think we disagree. Your point is, in ideal conditions "pulling the clutch in helps." I concur. But I suggest the wider picture applies.