Death of a GS

Whatever the main and contributing causes of this particular 'off', one thing is clear: on the road or track, your body position should be such that it allows the bike to be as upright as possible for maximum adhesion. If you stay more upright, the bike has to lean over further to compensate at the same speed, pushing the limits of the tyres and decreasing the margin before something solid touches down. Neither of these things are positive whether in steady state, under braking or under acceleration. Whilst they may help, neither traction control nor ABS Pro can change the laws of physics.

We will probably never know exactly what happened here but, whatever the cause(s) of this 'off' (catastrophic loss of control is never 'just one of those things'), we can all examine our cornering technique to ensure we're working with our bike and not against it. It's an I'll wind, etc.
 

I think the flashing is due to the way the reduced brightness of the rear light is arranged when full brake light brightness is not required. If you measure the voltage of the rear light supply with a multimeter on the DC setting it normally reads something like 3 V and when the brake is activated it jumps up to the standard 12 V or so. This is not normally achieved by generating a steady 3 V supply for the rear light.

Instead, what I believe happens is that the 12 V supply is chopped up into on and off segments, in this case roughly 1 period on for 3 periods off, so it is on for about 1/4 of the time, which a meter averages out to 3 V. This flashing is generally fast enough that human persistence of vision cannot see it, just like you can't see that a TV picture or video on a computer actually consists of a stream of separate pictures displayed at 25 or 50 frames per second, and just like you cannot see that a domestic light bulb only comes to full brightness every 1/50th of a second, which can also cause a strobing effect on video recordings.

I think what happens is that because video is captured as separate frames a short time apart, then when you take video of the rear light some frames will catch it in an on period and some off, but if the video frame rate is not precisely synchronised with the rear light flashing, which is unlikely, then the recording will probably miss quite a few of the on periods which happen between frames, and so would make the on and off rate appear slower and therefore visible on the video playback. For example, as an extreme case, if it so happened that the light flashed on briefly only in gaps between frames then the light would appear to be off.

When the brakes are applied the LEDs get a steady 12V supply, so are much brighter, and are continuously lit so should appear in every video frame while the brakes are on.

Fred
 
.... I've had offs and I've tried (mostly) to work out why, sometimes me, sometimes no reason why the bike let go.....


I think the big physiological dilemma with crashes (and to an extent the reason for this thread) is that when it's obvious what's happened and you can kick yourself for doing 'X', then you can put it to bed straight away and not let it affect your confidence.
(I remember seeing an interview with Casey Stoner who had just crashed, and he was fuming with himself because he'd just lost his front, he knew exactly what he'd done wrong and he was berating himself for doing it. So .. no issues with confidence next time out.)

But when you really can't get your head around what you've done wrong, thats when it can really knock you side ways and for months afterwards you can really struggle with confidence in the corners. So I can sort of see why Steve is keen to try and work out for himself what's gone awry. (Think of all the riders who struggled with the Ducati in its early days, how the bike kept loosing it's front end, and that the riders were pulling their hair out saying that they're doing nothing wrong, but the bike just crashes. Those riders then loose confidence in the front end and it all goes from bad to worse .. )


Continuing on with the theme of weight and the transference of weight, suspension settings will play a big part in how your bike actually grips, and how the weight is distributed front and rear. I understand that Big Steve (!) was probably on one up settings. With a big guy sitting on the bike, and maybe a top box or roll bag behind him (can't quite tell what it is) how will that bike sit on the road? Well it will probably be quite rear biassed.

As you roll on and off the gas, again you transfer huuuuge amounts of weight to either the front or the rear tyre.
Out of interest, ask any decent racer how he corners and he'll tell you that he brakes late and into the bend. Why? because he's deliberately loading his front end for grip. (Obviously they're playing with fine margins and if he hangs onto that for too long .... ).

Ask any trained road rider how he corners and he'll probably tell you that he gets all his braking / off gas done whilst upright, and then comes off his brakes, picks up the gas and drives through the bend. And that's very much me - I do that ..

The racer will scoff at that style and tell me that at the very point i'm tipping into the corner and want grip on my front, I'm actually taking it away by picking up the drive and transferring that weight away from the front to the rear, leaving my front light just as I start to corner!!

Whilst that is a separate debate in itself, (and I would certainly not be one to advocate loading front tyres into corners on the road ... I'll stick to my style thanks .. ), it is worth thinking about how you transfer weight forwards and backwards on a bike with your throttle, and of course with your suspension.

I remember being on a touring holiday with Rosy a few years ago and she had packed a ridiculous amount of stuff on the bike - I could hardly stand the bike up right off it's side stand. Day one of the Alps and we're climbing, in the rain, two up with her entire fucking wardrobe in the panniers and Top box. Even though the GS electronic suspension was set to two up plus luggage, the front felt awful; vague and light, all that normal weight from a normal balanced bike had gone. Now add into the mix traveling up the descents towards Gallibier .. Vars ... Telegraphe .. in the rain, and the front was just no where. It felt like Dennis Hoppers chopper on Easy Rider. Transfer even more weight away from it as you pick up the drive around those wet up hill hair pins, and you can see just how easy it would be to loose the front.

So this is why some solo riders, even with no luggage, often like to ride their bike on solo plus luggage. That increase in preload at the rear will just cant the bike forward a bit and put a bit more weight on the front tyre.


Steve ... as a big guy, I would recommend you do this. Yes you're on your own, you may have next to no luggage (Johno does the same and wears his pants for about four days), but jack that back up to cater for your size and consider permanently riding in one up + luggage.

I am still of the opinion that the front actually has the tinniest of slides first, and that this then sees the whole bike loose traction and the back wheel come round. And that's probably happened because the front is generally a bit light, you're carrying your corner speed into the bend in the vid (nothing wrong with that), I think Rik was saying it was ever so slightly up hill, and then you open the gas and drive .....

You've lined all the planets up for just a tiny tiny slip of grip ... :thumb2
 
I think the big physiological dilemma with crashes (and to an extent the reason for this thread) is that when it's obvious what's happened and you can kick yourself for doing 'X', then you can put it to bed straight away and not let it affect your confidence.
(I remember seeing an interview with Casey Stoner who had just crashed, and he was fuming with himself because he'd just lost his front, he knew exactly what he'd done wrong and he was berating himself for doing it. So .. no issues with confidence next time out.)

But when you really can't get your head around what you've done wrong, thats when it can really knock you side ways and for months afterwards you can really struggle with confidence in the corners. So I can sort of see why Steve is keen to try and work out for himself what's gone awry. (Think of all the riders who struggled with the Ducati in its early days, how the bike kept loosing it's front end, and that the riders were pulling their hair out saying that they're doing nothing wrong, but the bike just crashes. Those riders then loose confidence in the front end and it all goes from bad to worse .. )


Continuing on with the theme of weight and the transference of weight, suspension settings will play a big part in how your bike actually grips, and how the weight is distributed front and rear. I understand that Big Steve (!) was probably on one up settings. With a big guy sitting on the bike, and maybe a top box or roll bag behind him (can't quite tell what it is) how will that bike sit on the road? Well it will probably be quite rear biassed.

As you roll on and off the gas, again you transfer huuuuge amounts of weight to either the front or the rear tyre.
Out of interest, ask any decent racer how he corners and he'll tell you that he brakes late and into the bend. Why? because he's deliberately loading his front end for grip. (Obviously they're playing with fine margins and if he hangs onto that for too long .... ).

Ask any trained road rider how he corners and he'll probably tell you that he gets all his braking / off gas done whilst upright, and then comes off his brakes, picks up the gas and drives through the bend. And that's very much me - I do that ..

The racer will scoff at that style and tell me that at the very point i'm tipping into the corner and want grip on my front, I'm actually taking it away by picking up the drive and transferring that weight away from the front to the rear, leaving my front light just as I start to corner!!

Whilst that is a separate debate in itself, (and I would certainly not be one to advocate loading front tyres into corners on the road ... I'll stick to my style thanks .. ), it is worth thinking about how you transfer weight forwards and backwards on a bike with your throttle, and of course with your suspension.

I remember being on a touring holiday with Rosy a few years ago and she had packed a ridiculous amount of stuff on the bike - I could hardly stand the bike up right off it's side stand. Day one of the Alps and we're climbing, in the rain, two up with her entire fucking wardrobe in the panniers and Top box. Even though the GS electronic suspension was set to two up plus luggage, the front felt awful; vague and light, all that normal weight from a normal balanced bike had gone. Now add into the mix traveling up the descents towards Gallibier .. Vars ... Telegraphe .. in the rain, and the front was just no where. It felt like Dennis Hoppers chopper on Easy Rider. Transfer even more weight away from it as you pick up the drive around those wet up hill hair pins, and you can see just how easy it would be to loose the front.

So this is why some solo riders, even with no luggage, often like to ride their bike on solo plus luggage. That increase in preload at the rear will just cant the bike forward a bit and put a bit more weight on the front tyre.


Steve ... as a big guy, I would recommend you do this. Yes you're on your own, you may have next to no luggage (Johno does the same and wears his pants for about four days), but jack that back up to cater for your size and consider permanently riding in one up + luggage.

I am still of the opinion that the front actually has the tinniest of slides first, and that this then sees the whole bike loose traction and the back wheel come round. And that's probably happened because the front is generally a bit light, you're carrying your corner speed into the bend in the vid (nothing wrong with that), I think Rik was saying it was ever so slightly up hill, and then you open the gas and drive .....

You've lined all the planets up for just a tiny tiny slip of grip ... :thumb2

Lessons for everyone !

Thank you Giles I don't care what everyone else says you are a decent chap :D
 
The appearance of something dangling from the bike on the previous corner is still troubling me, especially as at the moment the rear goes there is just the slightest hint that it lifts before it slides, though the footage is so blurry that I could well be imagining it. Further to that, does anyone know what the apparently extraneous bit of black tube is that is lying across the shaft drive and heel plate in the third photo at the beginning of the thread?
 
Lessons for everyone !

Thank you Giles I don't care what everyone else says you are a decent chap :D

Plus 1 on that. Thanks for taking the time to explain all that in detail. I wear a heavy riding jacket, plus with the aluminium panniers and top box, although I'm only 82 ish kilos, I still ride with the setup for 1 rider as I like to get my feet down as planted as possible when stopped. Next time out I will be on 1 rider plus luggage.....:beerjug:

Just to add most of my riding is in the mountains around Ronda, so all twists and turns and up hill and down dale, so not too dissimilar to the Picos.

Glad Andy was able to walk away ok.:thumb2
 
Plus 1 on that. Thanks for taking the time to explain all that in detail. I wear a heavy riding jacket, plus with the aluminium panniers and top box, although I'm only 82 ish kilos, I still ride with the setup for 1 rider as I like to get my feet down as planted as possible when stopped. Next time out I will be on 1 rider plus luggage.....:beerjug:


Yes, imagine trying to pick up and carry your aluminium panniers and top box - they'd probably be pretty heavy .. !


(Only 82 kgs??! Ha ha .. I'm a racing snake at 75 ... :D)
 
Yes, imagine trying to pick up and carry your aluminium panniers and top box - they'd probably be pretty heavy .. !


(Only 82 kgs??! Ha ha .. I'm a racing snake at 75 ... :D)

I'd go further and say that you'd be best setting tyre pressures for load as well...
 
Well now ...

I have now seen the video, and I've got to say ... I am quite surprised too! I was sort of expecting lairy speeds and lairy lean angles and it's all pretty sensible! So I can understand your head scratching.

Personally, I think he pushes his front first. We can all see his back coming round, but I think it's his front that goes first - just by the tiniest amount, and it all goes wrong from there.

I don't want to come across as one of these wankers that tells you how to go round a corner .... but ... :D :D

What I would say is that 'Steve' looks a pretty big guy and sits very still on his bike, he also looks like he rides on his insteps? (Hard to tell exactly..). So when you're a big, still sack of spuds, on insteps, there's very little input from you in terms of moving your body about and using your weight. You really are the ultimate passenger along for the ride and the bike is going to be the boss. Being 'still' is not such a bad thing - the ultimate swan on the water style is 'quietly efficient' (Page one, paragraph one ..!) but there's a balance to be had between being so still on your bike that you give it no input what so ever, and of course being lairy and hanging off and all that shit that we're most definitely not talking about.

The perfect balance in my very humble opinion, is a very active torso, very very relaxed elbows, definitely riding on the balls of your feet and a head that sort of leads the way into corners (Think chin towards the leading mirror).

What caused Steves tyres to let go? (Front I think) I've absolutely no idea?! (We could talk for hours on 'easy in, hard out', 'tyre grip trade off', acceleration sense etc etc), but (heres the wanker advice bit .. !) by being so still and 'unanimated' if you like, once that front had a little tiny slip, there was no loose rider input to be able to catch it and recover, there was no body weight to move about and be 'active' and 'involved' in the bikes steering and manourvering. What does your head weigh ? six or seven kilos? What about your upper body and head 35 / 40 kilos? That is a lot of weight! Thats an olympic bar and two 20k plates! Now imagine putting that on a waiters tray and getting him to hold it balanced with one hand. You'd only have to move that weight about a 1cm for the tray to collapse in the shift of weight. So what you do with your body weight or ... what you don't do with it, plays a huuuuge bearing on how your bike behaves, how it's balanced, and how that weight can affect grip.

Because Steve looks like he's along for the ride if you like (bit harsh .. sorry Steve .. but you get my drift) the momentum of the bike and it's little initial slide in the corner takes over, and once it's going .... it's going! Would a more 'active', 'involved' 'looser torso' 'just move that body weight about a tad' rider have either reacted more quickly to the front slipping or better still, prevented the front from slipping altogether ?? Who knows, but for my money, if Steve is scratching his head and is thinking 'are there any lessons to be learned from that', I'd say yes .... be a tiny bit more physical with your weight on the bike and move it about just a little bit.

(NB ... This is why off roading is so good for your skills!!)

I've looked through Youtube trying to find some examples of non lairy body movement and can't really find anything that appropriate, but this link is a reasonable example of upper body involvement (notice how he sits still in the saddle so no hanging off and knee out) and how he is using his arms and body weight to his advantage.

<iframe width="854" height="480" src="https://www.youtube.com/embed/fXWVYtsf43Y" frameborder="0" allowfullscreen></iframe>

OK , anyone here understand and buy into all of that ? Sorry Giles and I hope you won't be offended but I don't.
Relaxed at the elbows I agree, in fact relaxed - period. Brain engaged body fluid. You need to be able to feel what your bike and essentially your tyres are telling you. Rocket science it ain't. If you are stressed or tense you will react differently to if you aren't. The only reason I move from instep to the ball of my foot is so I don't wear my boot out when I lean over. Nothing to do with weight distribution or 'feel' for what the tyres are doing. All of that is through the main point of body contact with the tyre / road surface interface i.e. my arse and the seat or my hands and the bars. What do I do if I feel a loss of grip at the front or rear ? Simple. I try to remove the cause. Usually it's either excessive lean angle, coarse steering or braking or excessive acceleration. Not usually the latter in my case. If the road surface or your bike in any way contribute to the loss of adhesion it makes no difference to the result of to the remedy. Remove the cause!
Take a look at this you tube of what the experts do and what do you see in every single example? They REMOVE THE CAUSE. Throttle off, brakes off, steering off.

You tube Biggest wobbles and best saves in MotoGp

Sorry can't post the link but I'm sure someone knows how.
 
OK , anyone here understand and buy into all of that ? Sorry Giles and I hope you won't be offended but I don't.
Relaxed at the elbows I agree, in fact relaxed - period. Brain engaged body fluid. You need to be able to feel what your bike and essentially your tyres are telling you. Rocket science it ain't. If you are stressed or tense you will react differently to if you aren't. The only reason I move from instep to the ball of my foot is so I don't wear my boot out when I lean over. Nothing to do with weight distribution or 'feel' for what the tyres are doing. All of that is through the main point of body contact with the tyre / road surface interface i.e. my arse and the seat or my hands and the bars. What do I do if I feel a loss of grip at the front or rear ? Simple. I try to remove the cause. Usually it's either excessive lean angle, coarse steering or braking or excessive acceleration. Not usually the latter in my case. If the road surface or your bike in any way contribute to the loss of adhesion it makes no difference to the result of to the remedy. Remove the cause!
Take a look at this you tube of what the experts do and what do you see in every single example? They REMOVE THE CAUSE. Throttle off, brakes off, steering off.

You tube Biggest wobbles and best saves in MotoGp

Sorry can't post the link but I'm sure someone knows how.

I believe Giles is correct ref moving about on the bike , which is really letting the bike move about under you . The more you fight it by staying still the more you effectively add extra steering input in to the equation .

Not sure about the braking into corners .

The reason why racers do it is because they can .
That's due to a lot higher grip level due slicks , constant road grip and hot tyres .

That's why as road riders we can't as we don't have any or very little of the requirements.
 
I believe Giles is correct ref moving about on the bike , which is really letting the bike move about under you . The more you fight it by staying still the more you effectively add extra steering input in to the equation .

Not sure about the braking into corners .

The reason why racers do it is because they can .
That's due to a lot higher grip level due slicks , constant road grip and hot tyres .

That's why as road riders we can't as we don't have any or very little of the requirements.
Allowing the bike to move under you is exactly what I do and am trying to explain. Relax your body and get tuned in to the feel of the tyres as they do their job. I find riding very uncomplicated and all the input I make is through the handlebars, the controls on it, the gear lever or rear brake. Am I along for the ride ? Absolutely ! I want to blend with my bike not fight or dominate it. I have no desire or need to be shifting my weight around to get it to from a to b. Why make hard work of what is in truth such an easy job.

So to clarify as I have just proof read my post... I am that sack of potatoes, my backside does not shift from side to side on the seat and my torso above it will be in line with the Centreline of the bike irrespective of the angle of lean. If my arse isn't in contact with the seat I have pretty much disconnected from what my tyres are telling me. Look where you want to go and relax. If you have overcooked it a bit you will make a better job of getting round if you can react quickly and smoothly.

Sent from my Lenovo TAB 2 A10-70F using Tapatalk
 
We can be certain

1 The brake light is not on at the moment of loss
2 the bike has lean ABS anyway
3 The data log on the sat nav indicates the bike was accelerating ( pulling through the corner)
4 Andy says he was not braking and that is good enough for me

The fact that you can't see the brake light on at the moment of loss could be due to the multiplexing LED - they are pulsed on and off just fast enough so that the eye does not normally register the multiplexing but aliasing with the camera 'shutter' then makes the flicker appear at a lower frequency - so the brake pedal may be pressed but you wont see the light at that instant.

I am not disagreeing with what Andy said, just pointing out that the brake light can lie when seen on film.
 
Sorry Giles and I hope you won't be offended but I don't.......


Ha ha ... hey, a healthy debate and a (slight) difference of opinion (especially between two job riders who both coach) in my book is a good thing.

My training at work was 'in house'. In my day new blokes on the bike team didn't go to outside forces or to Driving school, it was done by in house trainers. I had two and they were chalk and cheese.

One was very old school, sat very still on his bike (looked like he was asleep), rode on his insteps with his toes pointing down and was the archetypal swan on the water. He was probably the smoothest biker out there and the local IAM examiner. He quite simply never put a foot wrong.
My other Mentor was .. well a bit lairy. Ex trials rider, fireblade owner, and blisteringly quick. Heavily into his sports bikes and again an exceptionally talented rider. He was very much a 'get on with it' rider and pulled his hair out with me and my (and I quote) 'Ponsy IAM style' :D

The two of them didn't really see eye to eye about many things and would sometimes contradict one another - I remember the lairy guy telling me off for 'riding in the gutter' on right handers. This wasn't a dig at me as such, it was because I'd just done a three week standard course with the other bloke who did 'ride in the gutter'. "Nah ... we don't do that ..' I remember him saying.

I see it as the students job, to go out with as many decent riders as they can, be that sponge, soak things up, and take the bits you like, and bin the bits you don't. I took bits from old school guy that I liked (his swan on the water and smoothness was excellent, and as it happens I took his ride in the gutter as well!!) and I took things from lairy guy and in particular his 'get on with it' style. And as a result, sort of formed my own style of riding.

I'd implore anybody else interested in training to do the same. Be a sponge, soak up the bits you like, bin the bits you don't ... :thumb2


Back to the thread .. and yeah ... I'm sort of a sack of spuds too ... nice and relaxed, sit still in the saddle (don't move my arse about) and yes ... it's easy - at one with my bike.
But I'm not that sort of John Surtees 1950's style that sits completely in line with his bike, I sit still in as much as I don't move my arse about, but I do move my upper body about quite a bit. And I guess that's a throw back to the lairy input in my training days all those years ago!

I see Steve as a little bit broom up arse John Surtees 1950's style !! It certainly hasn't caused his crash - of course not, but my point here is that if you are ... Ummm ... I want to say loose but Phooey won't like that :D .. how about pliable, a bit flexible, balls of feet not insteps, then certainly for me, you feel more underneath you and in my opinion you have more 'thousand signals per second active suspension' in your fingers and toes. That was my immediate impression with Steve riding style - a bit upright and arms like little steering dampers ...

It's probably all bollox though ..... :D
 
The fact that you can't see the brake light on at the moment of loss could be due to the multiplexing LED - they are pulsed on and off just fast enough so that the eye does not normally register the multiplexing but aliasing with the camera 'shutter' then makes the flicker appear at a lower frequency - so the brake pedal may be pressed but you wont see the light at that instant.

I am not disagreeing with what Andy said, just pointing out that the brake light can lie when seen on film.

As I said in a previous post, I believe the LEDs are only pulsed when in tail light mode, and this is done in order to reduce their brightness from the maximum output that is only used in brake light mode. In the case of the GS it appears that you get the equivalent of an approximately 3V supply voltage (at least that is what I have measured) due to the ratio of on time to off time used. I would expect the maximum output of the LEDs would be used when the brake light is required, and this is pretty much confirmed by the fact that when the brakes are activated the measured supply voltages increases to the full 12V.

There are definitely places in the video where the rear light increases greatly in brightness, and looks just too bright for a tail light, but it difficult to say that it is definitely braking as the aliasing with the video capture frequency may produce apparent differences in brightness as well as the on/off pulsing effect.

(I expect you are just trying to keep your explanation simple, but there is no mechanical shutter, just a periodic readout and reset of the sensor, generally 25 or 50 times a second.)
 


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