Why does the rear wheel lock with early clutch?

[skithepowder]

When I was doing my DAS I was told that if you pull the clutch in early during an emergency stop the rear wheel locks. Why does this happen?

Would the rear wheel lock if you held the clutch in for a few seconds while changing gear?

What would happen if the bike cut out while riding due to some problem, would that also cause the rear wheel to lock?

[Paxovasa]

The rear wheel will lock up if you are pulling hard on the front brake while you pull the clutch in and you are pressing hard(ish) on the rear brake lever. The cause is the weight of you and the bike are forced forward so the rear will be light and it does not take allot for the rear to lock up.
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Suzuki GSF600 K3 (in the fastest colour, black).

[supZ]

whoever told you that is talking crap.

however, i think i might be able to explain the reasoning.

with the clutch out the engine is driving the wheel, with the clutch in it is freewheeling (i.e. just spinning on the momentum it had and/or movement across the road)

when emergency braking all the weight will be on the front and if you're pressing the rear as well there wont be much in the way of road contact to keep the wheel rolling with the clutch in making it far easier to lock up.

its not pulling the clutch in that locks it up, its the brake without any resitance against the wheel (engine or road contact) to keep it rolling that'll do it.

my advice would be to forget about the clutch and just get the stop completed. they dont mind if you stall, its almost expected, however, personally id think about pulling it in just at the moment before you come to a halt (i.e. just before it stalls)

also, dont pull the front and then push the back. just rest your foot on the back brake and let the momentum of you pulling the front roll you forward and put pressure on the back brake pedal. you'll reduce the risk of locking the wheel under braking using this method.

hope that helps
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CBR954RR - Daily toy
CBR600RR - Trackbike

[stinkwheel]

To be honest, my experience is the opposite. Except perhaps at the very last moment where the engine ticking over would pull the wheel round a bit. Big singles will skid the rear wheel under hard braking without even touching the back brake due to engine braking.

As has been said. A token application of the rear brake just to steady the bike is the way forwards. If you're doing a proper emergency stop, the back wheel is hardly touching the ground anyway.

In terms of the test, I was ahem "encouraged" to not brake quite as hard but to let my weight be thrown forwards so the bike dived heavily on the forks and looked like it was braking harder than it was in reality. This was on the old style test where you went round the block though, they have more of an idea of your stopping distance on the new style test.

In any case. You're riding to pass the test so do it like the instructor says. As has also been mentioned, stalling is not an issue providing you take the correct action after stalling so concentrate on the braking, not when you pull the clutch in. The aim is to stop as quickly as possible and under control.

If I really throw out the anchor these days, it's not unusual for the back wheel to lock and skip about even without the back brake but that's down to practice and getting used to your bike. You don't really get a feel for it until you've locked the front a few times
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Frost]