Stiff penalties for leading a ride out

[AlanH]

If there are ten vehicles in the convoy and they are traveling thirty meters apart the last vehicle in the convoy has to slow down 300 meters from the braking point. The first vehicle can accelerate as soon as it has rounded the bend. The last vehicle is slowed to the bend speed for longer than the leading vehicle so the gap will increase. The only way for the following vehicles to close the gap is to increase its speed.

That model is only true if the distance between vehicles is not allowed to go below 30 metres. Practically speaking, in a slow bend you bunch up. As you come out of the bend the distance increases. If the time between each bike is kept constant and the distance is allowed to vary, there is absolutely no effect.

In my experience, the catch-up situation most frequently occurs when the leader makes an overtake and the followers miss it. Another common scenario is if the leader is more skilled, smoother and carries more speed in the corners. The others, who go so slowly around corners they may as well get off and push it around, use excessive speed on the straights to make up for their rubbish cornering.

[Mabels Old Man]

This shows up as a practical problem for new riders who natrually don't want to lead a ride but would prefer to follow and learn. They find themselves being left behind and think they are slower than the leaders. When they try to keep up the accidents occur.

This is why it's always good to use the drop off system when on a ride out. Everybody rides at their own speed and nobody gets left when it's used properly

[Traveller]

That model is only true if the distance between vehicles is not allowed to go below 30 metres. Practically speaking, in a slow bend you bunch up. As you come out of the bend the distance increases. If the time between each bike is kept constant and the distance is allowed to vary, there is absolutely no effect.

In my experience, the catch-up situation most frequently occurs when the leader makes an overtake and the followers miss it. Another common scenario is if the leader is more skilled, smoother and carries more speed in the corners. The others, who go so slowly around corners they may as well get off and push it around, use excessive speed on the straights to make up for their rubbish cornering.

The model was described this way to illustrate why the people following find themselves having to reach higher peak speeds. Bunching and riding abilities all vary the model but this only changes the difference in peak speeds required to keep up. Ie the more bunching the lower peak speed needed and vice versa. On motorways this phenomenom doesn't show itself much but on winding roads with junctions and roundabouts the gap widens, these are the locations where playing catchup is most risky. In practical terms the more vehicles in the group the more clearly the model is recognisable.

The point I am making in relation to this post is, when leading a group, even you were following the posted limits, could it be consrued that as you were aware that the following riders would have to exceed the limits to keep up then as you were part of this 'Joint Enterprise' are you culpable?

Re the apparantly slower riders at the back keeping up, there are different abilities and different bike characteristics but I wonder how many lead riders think they are 'riding gods' because the the others fall behind for this reason and how many followers lose confidence in their ability as a result?

[Austin]

In my experience, the catch-up situation most frequently occurs when the leader makes an overtake and the followers miss it. Another common scenario is if the leader is more skilled, smoother and carries more speed in the corners. The others, who go so slowly around corners they may as well get off and push it around, use excessive speed on the straights to make up for their rubbish cornering.

its not just overtakes or cornering skills that cause this - junctions, short sections of speed limits, lights, pedestrian crossings and others all cause the group to get spread out. This is why whenever I lead a group I have spells of "normal" riding followed by a spell of slow riding to let the group catch up even if we are using the 2nd man drop off system. I also, generally won't overtake on stretches or road where I don't think the whole group will get past within a reasonable amount of time. If I do I will often slow so I am going just a little faster than what I have overtaken so I don't disappear off into the distance.

[Dee Duble Yuh]

When a group of vehicles run in convoy the following vehicles have to reach higher speeds in order to keep up. When the leading vehicle in a convoy has to slow down (eg for a bend in the road) the rest of the vehicles in the convoy are slowed by the leading vehicle, not the bend in the road.

<snip>

I think this contributes to the types of accidents that involve new, or less confident riders in a group.

It's a phenomenon known as "The Bullwhip Effect" that is seen in a variety of situations (e.g. Goldratt's Boy Scout hike). Speeds vary however a following rider (1) can never go in front of the rider ahead but (2) can drop back. Overall result is following riders tend to drop back. Differences in skills amplify the problem but are not the root cause. Mike makes a good point about the second man drop-off system. In extreme if the leader gets too far ahead eventually there will be no "second man" so he or she has to stop.

Although agreeing to deny knowing each other is a nice idea, a whole string of muddy adventure bikes with alloy panniers is going to look like a joint enterprise to anybody.

[AlanH]

Bunching and riding abilities all vary the model but this only changes the difference in peak speeds required to keep up. Ie the more bunching the lower peak speed needed and vice versa.

If the time between riders is kept constant, there is no higher peak speed required to maintain the same journey time. If the time is great enough, the other factors will even out too. Occasionally the leader will not have an opportunity to make an overtake, but following bikes will. Of course, if the time is great enough, everyone is really travelling independently so it's not really an issue.

On motorways this phenomenom doesn't show itself much

except with tailgating vehicles which is a great example of the effect. Front vehicle nice and smooth rolling on and off the throttle and the further back you get, the more pronounced the on the power one minute, on the brakes the next. Put some time between the vehicles so they do not influence each other and harmony is restored.

The point I am making in relation to this post is, when leading a group, even you were following the posted limits, could it be consrued that as you were aware that the following riders would have to exceed the limits to keep up then as you were part of this 'Joint Enterprise' are you culpable?

My view is that the followers have a choice whether to obey the limits. As long as they know the route (and that in itself is a compulsion factor if riders don't know where they are going) falling behind shouldn't be an issue and, as long as their ability is similar, they will never fall behind by much on average.

[StumpyFingers]

How many bikes together construe a group ride out?

If you are out on the road section of the driving lesson and there are 4 bikes together 3 learners and 1 instructor does that count?

[Austin]

How many bikes together construe a group ride out?

2 or more?

If you are out on the road section of the driving lesson and there are 4 bikes together 3 learners and 1 instructor does that count?

I would say so. Why wouldn't it?

[pdsquire]

A quicker bike, ridden sensibly, should be at the back. It's just what you have to accept if you are going to ride out in a group. That rider can ensure no-one is left alone and can assist the confidence of any back-marker by swapping position and demonstrating techniques.

It's the same with mountain craft: it's a dangerous environment; the group has to ensure that the least experienced or slowest member sets the pace and is only encouraged to push harder by someone who can show them with caution, confidence and skill.

Did you get that PDSquire, Jones and Snaphappy

Dunno what you're talking about Tom, unless you are referring to when we ease past those speeding sports bikes. Naughty scamps, they are! And so resentful!

[Traveller]

Although agreeing to deny knowing each other is a nice idea, a whole string of muddy adventure bikes with alloy panniers is going to look like a joint enterprise to anybody.

Thats why I have plastic Givis .