Tailgating - how to react

[Angelfishsolo]

Well, you could just as easily say "what type of car and what type of brakes". The stopping distances never distinguished between drum brakes and disc brakes on cars, and they don't distinguish between a Fiat 500 and a Range Rover.

Serious question. How many cars on the road today still use drum brakes? I was under the impression that all cars used disk brakes these days.

The point about cycles is that there are many types of rim brakes used and the stopping distances even when new vary wildly. I would guess with a greater distance range than cars.

I take your point about car types. IIRC the stopping distances used today were taken from a Triumph Dolomite or some such car.

 

[tyred]

How come people have looked into the stopping distances for cars and given standard rules and regulations, but not into the stopping distances of bikes. It isnt exactly hard.

All you need to do is set a stopping distance at 20 mph, and then the other speeds are easy. It is simply to work out how much pressure you need to apply and how to adjust you brakes accordingly. People normally have their brakes so that they are not rubbing when riding allong, but a little bit of pressure starts to slow the bike down.

Yes the highway code is not the law but many of the things in it are the law. ("Code" not rule or regulation). As the Highway Code is advisory, then it should be allowed to have as much information in it as possible. I personally feel that the Highway Code is not detailed enough, and doesnt give enough information to be safe on the roads.

It doesnt mention anything about how to act when you are involved in a collision. Nothing about cyclists stopping distances, or how to ride in different weather conditions.

None of it.

I would say it is up to you to know the stopping distance of your own bike (or car) and leave space accordingly. There is so much variation of stopping distances between car brakes and an even bigger variation on bike brakes. Rod brakes on chrome rims on a wet day - just say a prayer if an obstacle unexpectedly appears as you won't be stopping anytime soon.

 

[Angelfishsolo]

I would say it is up to you to know the stopping distance of your own bike (or car) and leave space accordingly. There is so much variation of stopping distances between car brakes and an even bigger variation on bike brakes. Rod brakes on chrome rims on a wet day - just say a prayer if an obstacle unexpectedly appears as you won't be stopping anytime soon.

 

[DrSquirrel]

Serious question. How many cars on the road today still use drum brakes? I was under the impression that all cars used disk brakes these days.

The point about cycles is that there are many types of rim brakes used and the stopping distances even when new vary wildly. I would guess with a greater distance range than cars.

I take your point about car types. IIRC the stopping distances used today were taken from a Triumph Dolomite or some such car.

Drums are in the rear of cheaper models often.

Most braking methods on a bike on the road will stop pretty similar.

How come people have looked into the stopping distances for cars and given standard rules and regulations, but not into the stopping distances of bikes. It isnt exactly hard.

All you need to do is set a stopping distance at 20 mph, and then the other speeds are easy. It is simply to work out how much pressure you need to apply and how to adjust you brakes accordingly. People normally have their brakes so that they are not rubbing when riding allong, but a little bit of pressure starts to slow the bike down.

Yes the highway code is not the law but many of the things in it are the law. ("Code" not rule or regulation). As the Highway Code is advisory, then it should be allowed to have as much information in it as possible. I personally feel that the Highway Code is not detailed enough, and doesnt give enough information to be safe on the roads.

It doesnt mention anything about how to act when you are involved in a collision. Nothing about cyclists stopping distances, or how to ride in different weather conditions.

None of it.

It doesn't matter, its a guide - you need to beable to stop for the conditions and your car. Many cars can stop well inside the "estimates" and im sure many can't. Added to that, without concentrating thinking time is larger too - specially with idiots that tailgate thinking they can stop sooner so they can drive closer.

2 seconds (in the dry, 4 in wet 10 in ice) is a MINIMUM suggestion anyway.


Yet - and I say this loosely - a large majority don't.


They bleet on how its getting safer and all that - imagine how safe it would be if people get their ****ing distance

 

[Angelfishsolo]

Drums are in the rear of cheaper models often.

Ok that I didn't realise.

Most braking methods on a bike on the road will stop pretty similar.

I beg to differ. At any sort of speed the hydraulic disks on the MTB will out-brake the callipers on my road bike by almost half the distance I assure you.

 

[DrSquirrel]

I beg to differ. At any sort of speed the hydraulic disks on the MTB will out-brake the callipers on my road bike by almost half the distance I assure you.

MTB on a road...
and *your* road bike.

Anecdotal...

 

[Angelfishsolo]

MTB on a road...
and *your* road bike.

Anecdotal...

Also my MTB and around 15 hybrids with v brakes (used on the Mentro Allan project) - Not so anecdotal now.

 

[DrSquirrel]

Anecdotal still..

 

[Angelfishsolo]

Anecdotal still..

So what would it take for it not to be anecdotal. A mass braking test or manufacturers publishing stopping distances of their bikes?

On what evidence do you base you claim there is little difference in stopping distance between bikes?

 

[MrHappyCyclist]

I beg to differ. At any sort of speed the hydraulic disks on the MTB will out-brake the callipers on my road bike by almost half the distance I assure you.

I think the hydraulic disc brakes on my new bike and the cantilever rim brakes on my old bike are equally capable of tossing me over the bars or locking up both wheels even on a dry road. I don't think the brakes themselves are the limiting factor, other than the fact that I have better control with the discs.

You're right, though; the stopping distances can only be only a rough guide in any case.

 

[SportMonkey]

A 29" (700c) wheel has a rough rim diameter of 620mm. A disc brake has a rough diameter of 180mm. For each minute turned a disc brake will need to exert around 3.5 times the force to stop, so if the pad is less than 3.5 times the size of a rim brake it cannot have the same stopping effect. You don't get as much variability either. It's all due to a bit of simple maths and the area this is all working over. Now, in my experience disc pads aren't a full 3 times the size of rim pads, and certainly to have twice the stopping effect would need to be twice that size so 7 times as large. I can also say from personal experience that my rim brakes lock my wheels on the flat if fully applied. You can't even call heat dissipation, as while the friction is large, the area dissipating the heat is far larger. So, for on road, rims brakes are better. Slick tyres should also be far better at stopping due to constant rubber contact, and the fact that knobbly MTB tyres are more likely to skid (you're sheering off a smaller face).

 

[Matthew_T]

I think the hydraulic disc brakes on my new bike and the cantilever rim brakes on my old bike are equally capable of tossing me over the bars or locking up both wheels even on a dry road. I don't think the brakes themselves are the limiting factor, other than the fact that I have better control with the discs.

Well under a lot of pressure, the rear wheel always locks up on any type of bike. I have had it on my Road bike many times, when I have been going downhill or stopping suddenly in the wet (or dry).

 

[MrHappyCyclist]

Well under a lot of pressure, the rear wheel always locks up on any type of bike. I have had it on my Road bike many times, when I have been going downhill or stopping suddenly in the wet (or dry).

That's because, provided the front wheel doesn't skid, the maximum deceleration you can achieve is just at the point before the bicycle does a "stoppie". At that point, all of the weight is on the front wheel and none is on the back wheel.

 

[Matthew_T]

That's because, provided the front wheel doesn't skid, the maximum deceleration you can achieve is just at the point before the bicycle does a "stoppie". At that point, all of the weight is on the front wheel and none is on the back wheel.

I have been told by other cyclists that you need to put as much weight over the rear wheel as possible, to stop it from skidding.

 

[gaz]

Stopping distances on a bicycle are all down to the riders skill and not the brakes. A modern cars stopping distance is all down to the brakes.