Gearing down to low?

[mudcow007]

Probably a stupid question this...but hey ho

Riding in this morning, I geared down a little bit too much for a corner.

when i came off the clutch, the back of the bike sorted of squirmed all over the place/ possibly wheel locked up (i haven't seen any scuff marks on the tyre or anything though)

Im guessing this was because the engine was rotating faster than the wheels/ sprockets so kinda did a bit of engine braking?

that make sense?

I normally tend to ride as clutchless as possible - as i'm lazy. Riding this way i never experienced squirmyness....?

[tom_e]

Releasing your clutch after downshifting while going too quick for the lower gear will result in your back wheel locking up unless you have a slipper clutch.

Clutchless shifts require you to match revs before shifting therefore it's near impossible to lock the wheel unless you really jump up and down on the shifter and crunch it into a lower gear.

[chris-red]

It won't lock because the engine is always turning, it's when the tire breaks traction to because the engine braking is so strong, keep practicing and combine it with hard braking, it's how you 'Back it in' to a corner.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[RhynoCZ]

Blip the throttle to prevent this from happening.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[stinkwheel]

A few things going on there, all of which reduce available grip.

1) You're under braking so the weight is transferring off the back wheel onto the front one.

2) You're cornering so there is a lateral force on your tyre.

3) You are under engine braking so the tyre is decelerating, applying longitudinal force through the tyre. Effectively because the energy stored in the wheel was, as you say, pushing the engine around rather than the engine pushing the wheel around.

There is a finite amount of grip available which is a function of the road surface (type, temperature, surface conditions), your tyre compound and the amount of downforce (weight) on the wheel.

If the sum of the three factors I mentioned exceeds the grip, the tyre will stop grippiung and begin to slide. That's what happened. The road is cold and wet, you applied a greater than normal deceleration force through the tyre and started to lose grip. The next step is a slide.

Another factor, you still on a lightweight 100cc 2-smoke? Could've been the frame/swingarm/forks flexing under power on a corner.
____________________
“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.

[stinkwheel]

[MarJay]

Gearing down too low?

Kids these days! In my day we just said that we had changed down one too many times... Gearing down too low makes absolutely no sense.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[RhynoCZ]

What the man above says.

When at high speed, the moment you disengage the clutch the revs drop, yet the wheel is still spinning quite fast. The moment you engage the cluch again, the engine has to match the speed of the wheel. It will eventually, but it also will lock up your wheel for a moment. It's quite like the other way around. Being stationary, rev the engine up and then just release the clutch lever.

Now, blip the throttle or release the clutch more sensibly. Especially when on a wet surface. Race drivers/riders used to blip the throttle when there was no such a thing as antihopping clutch. Bliping the throttle is way quicker than slipping the clutch.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[G]

The trick is to leave it a bit later so you're starting to lean, then knock it down a gear too many so the rear wheel is spinning slower than the road speed and breaks traction. As the bike slows down, use the rear brake to keep the rear wheel slowing down faster than the bike, so it stays sliding.

(Caution... you may crash, thought I never have approaching it a little carefully.)

[mudcow007]

Cheers all its does all kinda make sense

I will keep at it, updates of crashes to follow....

Oh this was on my 4 mega tonne Bandit.

[notbike]

Clutch in, blip throttle a bit or a lot depending on engine note/speed, clutch out.

Never worry about locking a wheel with gears again.

[RhynoCZ]

One more thing, the gear downshift happens during the throtle blip. Practice holding the throttle grip and operating the brake lever with your middle, index or both fingers. I use the middle finger on the brake lever and the rest of the hand firmly holds the throttle.

The moment you get all this right, with a smooth downshift, you're gonna feel like your life is finaly complete.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[chris-red]

[mudcow007]

rear wheel im guessing

[M.C]

[stinkwheel]

[thx1138]

I made a mistake on my Honda the other day, been riding my 2stroke for the last fortnight and forgot that the engine braking on my Honda is relatively heavy in comparison, didn't exactly lock up, it just sort of 'complained to me' about it.

[G]

Had a slipper clutch on a few bikes (including the KTM690).

Only time I've beenparticularly graretful of them is when trying out race shift on 675(s) on track - means that when you do mess up and change down instead of up coming out of a corner, nothing really bad happens.

On the road, haven't found any real need.

[Old Git Racing]

Practise this more and become a god of backing it in all crossed up. Man up.

OGR.
____________________
2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[Dave70]

I accidentally did the same as OP once, I didn't like the result at all. I have no intention of trying to purposely carry out such a thing again. In fact, one of my life missions, is to make sure it never happens again.

Does this mean that I have to hand in my man card now.
____________________
There ain't no devil, there's just god when he's drunk.

2012: R125 killed by white van. 2016 R125 killed by 30,000 miles of redline. Current: 2016 Kawasaki ER6f.

[RhynoCZ]

[Wafer_Thin_Ham]

[trevor saxe-coburg-gotha]

[Fin]

I often lock up the rear wheel on my divvy while engine breaking, I even blip before down shifting, just not enough, and I don't use the front brake enough.

[MCN]