Its slippy time!

[Le_Quack]

I had my back end step out yesterday evening at a roundabout, held it but reminded me why I shouldn't lean in so much on that roundabout when it's wet and why I was getting new tyres put on today.

Also thinking fo breaking out some warmer gloves, or at least some glove liners.

[mottza]

One the pie and mash ride I had the back end slip several times. The tyres were low so always check them. Oddly it still slipped after some corrective topping up of air.

[irev]

When somebody tells you about reading the road, they are not suggesting you rely on what you saw that morning, but are looking at the road as you ride in the "now".

Being downhill explains why the rear brake locked up and you slipped. Motorcycle braking is all about weight and grip. If you have no weight on the tyre it will more easily loose traction with the road as it also looses grip. Sound like you do what many riders do and think you should rely more on the back brake and times like this catches it out. Your real braking is from the front wheel as when you first start to brake you load up the wheel, shifting the weight of the bike forward, increasing the grip between tyre and road. Going down hill is like riding on the horizontal with a slight front brake applied. The weight of the bike is already forward.

Downhill braking should start with the front and ease on the back to the point the back starts to feel to light, the point of breakaway is being reached. if it does start to slide or lock, ease off the rear brake and the whole bike will come back into line.

If you get the chance, do scrambling off road on a proper bike. I rode Enduro when I started riding in the 80's and this taught me a lot about braking. Another useful site for winter riding advice is: http://www.lazymotorbike.eu/" onclick="window.open(this.href);return false;

Couple small corrections, if I may:

1: Total grip is finite, it cannot be increased or decreased by the transfer of weight.
2: While your advice may be suitable for some types and makes of scooter, the simple fact is that almost all scooters have a rearward weight bias.
3: Total braking capacity accrues from correct interpretation of the total grip available from BOTH front and rear tyres, not the front alone.

In the light of the above may I respectfully disagree with your approach to braking in these conditions... although I completely agree about being 'in the moment'. What you describe suits a dry road whether level, downhill or uphill but in the wet on a downhill slope the priority is to maximise grip for retardation purposes, not transfer as much weight as possible to the front tyre. What you SHOULD do is start with the front, then add the back, then slightly increase the FRONT AND REAR TOGETHER until the back starts to feel light.
Not the rear. And certainly not the rear alone.
The action of transferring weight reduces the grip on the rear tyre, but only in a modest sense on the road on a road machine or scooter, unless you are a GP racer or on a suicide mission on the street, and a road rider ALWAYS looks to use a balance of front v. rear to access the grip that is available from both tyres.

This is precisely why ABS is such a boon as it enables a rider to practice, practice, practice searching out the limits of grip and the relative merits of braking styles to suit the conditions, knowing that one won't overstep the mark. It also allows the user to have greater reserves of steering available as modest inputs won't overload the front tyre.


Of course this also goes to the fundamental misconception in all classes of road racing that front weight transfer is good. What a shit lack of understanding of basic physics, and a very good reason why the current 'high headstock' designs have long since passed the limits of improvement to braking capability and why we see increasing problems with brake judder and fork stiction because no-one wants to accept their bicycle design is steam age, and the modern tyre is on the limits of adhesion at the front while the rear is waving uselessly in the air because of bad design, not good braking.

Two Tyres Good. One Tyre Bad.

addendum: On some scoots I have seen a significant reduction in overall braking distance by modifying the style above to front brake first, then rear brake, then increase rear brake alone using the 'four finger shuffle' approach on the back brake lever, rather than the front. We are not riding motorcycles and the genuinely different design elements (typically: rear weight bias; lower headstock height; lower CG; smaller wheels; greater ratio of unsprung weight etc) all conspire to require a different approach.

[ridinhigh]

I spent 19 years on the railway, leaf contamination could end up like a hardened black coating which is tougher and slippier than a teflon coated frying pan.
Not unknown for the speedo to drop to zero while the train is still doing 90 or so.
Scary stuff....

I spent longer on railway and retired there ,and i do agree with what you have written, about leaves on track.

[SOLO]

Ferrit good stuf & irev good write up, you have both manage to confuses me on who is right and who is wrong on correct braking........that link you posted is a very good read .....

[Ferrit]

One the pie and mash ride I had the back end slip several times. The tyres were low so always check them. Oddly it still slipped after some corrective topping up of air.

Reminds me of riding behind Stevo on that very wet Mersea Island rideout where his Fuoco kept spinning out the back end on every corner

[Ferrit]

Irev, sorry, re reading my write up I realise it does read as apply front hen only back but that is not intended, it should read as you say. When I said then start using the back I did not intend to give the impression you ignore the front!

Grip is finite, but there is a range until you reach that finite point and that is why it is recommended to load the front. Try riding on wet mud when you do not do this and you will find the front wheel washing out faster than you can scream "shit"

[irev]

Irev, sorry, re reading my write up I realise it does read as apply front hen only back but that is not intended, it should read as you say. When I said then start using the back I did not intend to give the impression you ignore the front!

Grip is finite, but there is a range until you reach that finite point and that is why it is recommended to load the front. Try riding on wet mud when you do not do this and you will find the front wheel washing out faster than you can scream "shit"

It's how you reach that finite point that one need be wary of. If you increase braking and load the contact patch then you risk washout without warning - Just watch last weekends WSB for absolute proof. Without ABS your chances of catching a front end washout are about as likely as the Pope shitting in the woods while a Grizzly takes control in the Vatican... A skilled rider can lock up the front and use it as a tool on the rare occasion that sliding a tyre is better than braking it while rotating.

The problem is that over-reaching of grip on the front suggest that the limits of grip were exceeded, whereas that is not true. What is actually true is that the limits of front tyre grip were exceeded through a combination of braking and loading. Meanwhile the rear brake sits underused when it could have had a contribution to make which would have added to the totality of braking effort - or to put it another way, the bike would have slowed or stopped, not crashed.

We could talk about the disk swept area reducing as the rotation speed declines, thereby reducing the overall braking effect for a given lever pull, but BOTH brakes have their contribution to make - and in slippery conditions having the ability to make the decision and change the operating methodology of the brakes will, in many cases, be the difference between safe, confident riding and falling off. One thing that can steady the weight transfer to the front is gentle initial application of the rear first.
But now we are getting into advanced braking techniques which belong on the training pad, not in a forum where words and instruction can be misunderstood.

What is actually required is practice, and the ability to change one's braking style to suit the needs of the moment without even having to think about it. And that is a skill derived from the science. And always will be, irregardless of the presence of ABS or TCS. Science says that if the rear was sliding then there was too much brake, too little weight, or a combination of both. The operation of the lever is down to the Scooterist, not Science. So that's where the buck stops.

[Ferrit]

I was taught that the only way I would learn to brake well was to go out and do it. Guys I ride with through work and blood running all have felt much better at braking for doing some off road riding as this really is riding with sod all grip most of the time. There is a lot of feel in braking and that can only be achieved by riding and learning from mistakes if you survive them

Locking any wheel is down to the rider, yes ABS can help probably in 90% of accident, the only thing that I really dislike about ABS is that it teaches people to grab a fistfull in emergencies and this may go against you the odd time. Nothing as you say would beat propert braking with ABS for those times you might reach the limit of grip and not realise you got there. The funniest thing I have seen is a guy trying to brake his ABS bike on wet grass at Peterborough show ground A time ABS will NOT help.

[Bluebottle]

Funny how simple things start to look really complicated once you start looking at them

Weight distribution on a stationary bike is easily measured but when you are cruising at a set speed here is moe weight on the rear

Low centre of gravity is thought of as a good thing but it means we have to lean over further in bends than a taller bike

Yet most brains can adapt through experience and make it seem so simple