Stoppies

[julian64]

One question

Your driving along at 40mph and a child runs out in front of you. This is a full on emergency stop!! you grab a giant handful of handbrake till your knuckles go white, while keeping your arms straight.


Will this end up as a stoppie on every motorcycle with you clearing the child by air, or will you simply lose the front wheel and go sliding into the child.

if you think there is a percentage chance of either, could you state the percentage and what bike. Road is a normal UK high street.


THERE IS NO ABS ON THE BIKE

Edited by julian64 on Tuesday 15th August 08:03

[trickywoo]

No finesse or skill on the front brake is more likely to lead to loss of traction and a crash rather than a stoppie.

[ssray]

Depends on the bike, k100 BMW will lock the front (non abs) as it has a low center of gravity Fazer 1000 will probably stoppie

[A500leroy]

modern hondas wont allow a stoppie.

[SAS Tom]

Depends on the bike etc.

Only bike I’ve had doing a stoppie was on a Thunderace on track. I changed the springs and damping and it didn’t do it after that.

I think on the road you’re more likely to lock the front unless trying to provoke a stoppie.

[bimsb6]

A stoppie normally means lifting your butt off the seat to change the weight distribution and avoids a front wheel washout .

Edited by bimsb6 on Monday 14th August 20:04

[spoodler]

I posted recently about how I "flipped" my old ('70s) Z650 end over end after grabbing too much front brake. I'd only just pulled away, as someone pulled out on me on a mini roundabout. I spent too long checking where they were and what they were up to, looked up and realised the car in front had stopped 90 degrees across the road to enter a driveway. I panic braked, next thing I knew I was just coming round in the back of an ambulance. The standard single pot 1970s brakes and budget Cheng Shins (or similar) were plenty enough to flip the bike end over end on a dry road. I thought I'd hit the car, but the Police told me I'd not touched the car and witnesses confirmed I'd locked the front and the bike had gone over vertical.

[Steve Bass]

Firstly, if you do either, your riding skillz are pants.... There's two brakes on an MC for a reason....

But, on a bike with modern(ish) ABS you're more likely to do neither of your scenarios... you may hit the child however if the ABS controlled stopping distance is less than the distance to the offending scamp...

[LunarOne]

I had to brake very hurriedly on a 1999 Bandit 600. Front forks ran out of compression and then the back wheel came up. Luckily by then my speed had reduced to very little, and the back wheel dropped back onto the tarmac without incident. It's the only time I've ever done a "stoppie" and I'm not sure I'd like to try repeating it as I don't have the skill to control it.

[LosingGrip]

I had a massive mental block when learning that if I did the emergency stop I'd go over the handle bars like I did on my push bike once.

I've never been able to get the ABS to kick in.

[julian64]

just modified it for no abs.

Obvious antistoppie, or abs electronics nullify the question

[spoodler]

Not sure quite what you're asking, or why...
If it's purely for a bit of theorising, or if you want to have a play... I'd imagine something like a cheap GS500 would be okay to practice on and shouldn't cost a lot when dropped.
Back in the '90s, we would pull stoppies and wheelies on most of our bikes. Bikes were, in the main, relatively standard, some were streetfightered. Pretty much all could be wheelied, including Z1000s, Sportsters and other unlikely looking bikes.
The big Zeds and the Sporties (lots of weight, long wheelbase) would mostly plough straight on with the wheel locked if you tried a stoppy and you'd be best off letting off the front brake before dropping it.
The best bikes for stoppies were a couple of grey imports, a 400 Bandit (I think, 'twas a long time back) and a VFR 400. Small light weight bikes which probably had the wheels and brakes off a bigger sports bike. The VFR400 had been modified with a "gull arm" back end and an upside down front end off a bigger/later Honda. The guy with the VFR could keep the rear end waggling about off the tarmac for a good distance. Neither was much good at wheelies tho'...
A GSXR 750 was good at both.

And, "Yes"... we did fall off finding out.

Anyone thinking, "What was the point?" - we were a lot younger then and just having fun. Not sure if any of that answers your question.

[black-k1]

There are a huge number of variables that will result in a different outcome but, basically, for a stoppie, there needs to be enough grip between the front tyre and the road to counter the force needed to rotate the bike around the front axle without the front tyre sliding.

Bikes with long wheelbases and/or low centers of gravity will require significantly more force to rotate (lift) them around the wheel spindle and, even in the best conditions, there likely isn't enough tyre/road grip to stop the tyre sliding.

Even on lighter, shorter wheel base bikes, the amount of grip (or lack of) due to surface imperfections, colder/harder tyres, non-upright approach of the tyre/bike will all contribute to the increased likelihood of a front wheel slide rather than a stoppie.

All of the above is why when people are choosing to do stoppies they tend to do so on lighter short wheelbase bikes and help the situation by moving themselves, thus the C of G forward and upward.

In answer to the original question, yes, it could result in a stoppie but is just as likely to result in a front wheel skid which, if not attended to very quickly, will, in turn, almost definitely result in a front wheel wash out.

[julian64]

Its a good question.

I suppose the question I'm asking is if in the scenario posted above. If you did a stoppie to try and avoid the child would an onlooking policeman say

1) Good on you, excellent piece of driving
2) You're an idiot, a stoppie is not an acceptable sight for emergency braking.

[spoodler]

julian64 said:

Its a good question.

I suppose the question I'm asking is if in the scenario posted above. If you did a stoppie to try and avoid the child would an onlooking policeman say

1) Good on you, excellent piece of driving
2) You're an idiot, a stoppie is not an acceptable sight for emergency braking.

It would probably be argued that you should have seen the child before such action was necessary... or should have been going slower... I doubt there are many scenarios where you could argue that a stoppy was part of a perfectly controlled stop. And, unlike when playing, an unexpected stoppy is likely to be caused by bad braking practice and catch you out badly. My accident related above, I missed the rear brake for some reason - I've very little memory of the accident, so will never know exactly what happened.

[Freakuk]

julian64 said:

One question

Your driving along at 40mph and a child runs out in front of you. This is a full on emergency stop!! you grab a giant handful of handbrake till your knuckles go white, while keeping your arms straight.


Will this end up as a stoppie on every motorcycle with you clearing the child by air, or will you simply lose the front wheel and go sliding into the child.

if you think there is a percentage chance of either, could you state the percentage and what bike. Road is a normal UK high street.


THERE IS NO ABS ON THE BIKE

Edited by julian64 on Tuesday 15th August 08:03

If you literally grab the brakes I'm going to say you'd lock the front and lowside, if you apply the brakes and then hit the anchors once the weight has transferred then you may end up stopping or a stoppie/over the bars.

[julian64]

Freakuk said:

julian64 said:

One question

Your driving along at 40mph and a child runs out in front of you. This is a full on emergency stop!! you grab a giant handful of handbrake till your knuckles go white, while keeping your arms straight.


Will this end up as a stoppie on every motorcycle with you clearing the child by air, or will you simply lose the front wheel and go sliding into the child.

if you think there is a percentage chance of either, could you state the percentage and what bike. Road is a normal UK high street.


THERE IS NO ABS ON THE BIKE

Edited by julian64 on Tuesday 15th August 08:03

If you literally grab the brakes I'm going to say you'd lock the front and lowside, if you apply the brakes and then hit the anchors once the weight has transferred then you may end up stopping or a stoppie/over the bars.

interesting. Are you saying the slower you apply the brake in an emergency the more likely you are to cause a stoppie.

[black-k1]

julian64 said:

interesting. Are you saying the slower you apply the brake in an emergency the more likely you are to cause a stoppie.

Grabbing the brakes does not allow the tyre to adjust to the transfer of the weight onto the front wheel, hence the likely skid. Applying the brakes progressively (not slowly!!!) allows the tyre to adjust which supports a greater load. That improves (shortens) stopping distances and increases the chances of a stoppie.

Edited by black-k1 on Tuesday 15th August 11:09

[KTMsm]

I'd suggest 99.9% of the time you'll lock the front wheel and fall off

I did a gymkhana event on a 690 duke and trying to win the shortest braking distance I stoppied - by luck rather than judgement - and won

[lukeyman]

KTMsm said:

I'd suggest 99.9% of the time you'll lock the front wheel and fall off

I did a gymkhana event on a 690 duke and trying to win the shortest braking distance I stoppied - by luck rather than judgement - and won

Who's kid did they throw in front of you?