Road signage - help with obscure questions please

**Crisis management** · 4th February 2007, 08:19

Originally Posted by Drum

No, I just mean that the tests are carried out using a car, and the speed advisory posted has nothing at all to do with bike physics or riding technique. Motorcycles and cars have different approach speeds and take a different line when cornering. Therefore the advisories are meaningless for bikes.

Ok, I see what you mean, but surely if we were to apply the same rules to bike corner speed, ie. a safe, comfortable speed that the lowest denominator bike could negotiate the corner we would have the same result - a speed perceived by most as too slow?
I would argue that the advisory speeds are useful in that they do give you a bit of a hint, thats all they are supposed to do anyway.

**Hitcher** · 4th February 2007, 11:27

And the approved measuring device for cornering speeds is a Parkinson's-afflicted Little Old Lady(TM), holding an egg in a spoon.

**Blackbird** · 4th February 2007, 11:30

Originally Posted by Speedie

I tend to use the signs as an indicator to the degree of tightness, or degree of difficulty....not even concerned as to what the actual speed that is written on the sign.
Say its a 75.... that means basiclly full noise, that corner wont be a problem. 65..maybe roll off throttle before entering corner and get a vanishing point going. 55.. gear down, slightest touch on the brake, then wind throttle on once in the corner. right down to 25s or 15s when it is nearly a second gear, full brake on approach corner.

Completely agree. I tend to register a sign at the almost subconscious level that there's something to watch out for.

**KLOWN** · 4th February 2007, 11:56

Originally Posted by Crisis management

I'm not sure about this one, I would have said a car (of reasonable quality) could always corner faster than a bike.....have the laws of physics been changed lately?

there has been endless debates about this so we won't get into another one but in a bike you are able to "cut" the corner and stay on your side of the road because you don't take up the whole lane where as a car is forced to not take an ideal line (if you don't count the people who cross the white line) because they are much wider vehicles.

also since we are on the topic of laws of physics a great deal of how quickly you can go round a corner is to do with the "grip" of your tyres or the "friction coefficient" as its called and bike tyres may have less of the tyre on the road but they have a greater friction coefficient to counter act this

**klingon** · 4th February 2007, 17:01

Originally Posted by Speedie

I tend to use the signs as an indicator to the degree of tightness, or degree of difficulty....not even concerned as to what the actual speed that is written on the sign.
Say its a 75.... that means basiclly full noise, that corner wont be a problem. 65..maybe roll off throttle before entering corner and get a vanishing point going. 55.. gear down, slightest touch on the brake, then wind throttle on once in the corner. right down to 25s or 15s when it is nearly a second gear, full brake on approach corner.

Yeah, the signs can be useful once you've worked out your own rule of thumb. In my little '89 corolla when fully loaded (the car, not me) I tend to go around unfamiliar corners about 15kph faster than the advisory, on condition the road is dry.

On a wet road, or when driving the Camry or the Audi, or when the loading is different, or on corners I'm familiar with, obviously it all changes.

And yes, I am a little old lady with an egg in a spoon

**paturoa** · 5th February 2007, 08:58

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...

**Blackbird** · 5th February 2007, 09:04

Originally Posted by paturoa

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...

A recommendation was made by some consultants in 1972 to round off advisory speeds to zeros (see Ixion's link in the post). The wheels of State grind exceedingly slow....

**Toaster** · 5th February 2007, 09:05

"Advisory" means exactly that. No matter what any sign says, you are required to drive/ride with due care at all times and drive/ride to the conditions. If you screw up, you are in the poo-cart.

**Toaster** · 5th February 2007, 09:07

I found that leaning over in the corners too close to the centreline created issues when meeting trucks coming the other way. Pays to take a conservative line sometimes!

**Drum** · 5th February 2007, 09:56

Originally Posted by paturoa

Has anyone else noticed that all of the recommended speeds end in 5, i.e. 55 65, 75, etc.

The only exception I have seen (noticed?) where they end in zeros, i.e. 50, 60, 70 and that is on Scenic Drive in the Waitakeres.

Go figure...

That is the rule. Advisories end in a "5" while speed limits end in a "0". Supposed to stop confusion between the two. Where you see an advisory ending in a "0" then it is either very old, or was incorrectly installed.

**Drum** · 5th February 2007, 09:57

Originally Posted by Toaster

"Advisory" means exactly that. No matter what any sign says, you are required to drive/ride with due care at all times and drive/ride to the conditions. If you screw up, you are in the poo-cart.

Exactly!!!

**paturoa** · 5th February 2007, 10:04

Originally Posted by Drum

That is the rule. Advisories end in a "5" while speed limits end in a "0". Supposed to stop confusion between the two. Where you see an advisory ending in a "0" then it is either very old, or was incorrectly installed.

They definitely end with zeros along scenic drive from the southern end. Some of them look very new too, but they maybe replacements.