ah, the crux of the matter. If I want to figure out which road to take, I have to park the bike, remove the mapcase, walk a few feet away and figure out which way to turn. Which is why GPS makes more sense, with a compass stashed away for when/if the electronics fail.

Compasses are for backpackers!

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quastdog
Chiang Mai, Thailand

Yah..... comes handy if the bike is on strike and the next village is mails away..... make sure your bike boots are well worn in...... and you know where you are and wat direction the GPS last had on it's display...........

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The trouble is that he was talking in philosophy, but they were listening in gibberish.

All of that parking/walking/removing isnt necessary......you can have your map in a case velcroed to the handlebar crosspiece/brace, easily visible, and a bike compass fixed to the bars too. Easy.

Compasses are for travellers.

These even more to this compassing lark than I realised.
Thanks for the replies people, appreciated.

I have one and knew how to use it once a plastic one with a scale on the side only need it a few times to find out what road to take at a "Y" and it dint have signpost. I have it out and "use" it when planing the next day ride looks good I think. Looks like I know what im doing. There nice to have when you need one but GPS will work better for most people.

People get lost all the time in Disneyland one of the things you need to know to work there even just to sweep the street is where every ride is and the ways out of the park. They also know there way around the underground of Disneyland.

A compass fixed to the bars won't always be accurate , you have to remove the compass from the influence of ferromagnetic objects to take readings so that it won't be affected by any residual magnetic fields .

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Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

A vehicle mounted compass needs to be swung. You take a bearing from a known objects position and find the error. You then correct for this error. The correct way is to fix magnets (aircraft version) or iron masses (old maritime solution) so the needle points the right way. Look at a ships binnacle in your local maritime museum, those 8 inch iron shot either side of the compass aren't there to hang your jacket on, they're the rough adjustment to allow for a hundred tons of steam engine a few feet away. The fine adjustment is under the dial and would usually be done at each port, hence lots of harbours have a location known as Compass point.

So called vehicle compasses are set up for an expected magnetic field (most 4x4's have 200-odd KG of diesel engine in the front) so they are better than the walkers compass in the tank bag. However, they don't entirely account for your vehicles magnetic field and i'd guess are worse on a bike where the small engine is below/behind (don't know, I never compared them). Hence, in the emergency where you know the paved road is somewhere North and the next town is west down that road, you will travel in roughly a straight line (actually a really huge arc as oposed to the 50 mile circle a compass pointing at the engine can produce). However, if the target is a 55 gallon drum of petrol in the middle of Australia, I'd want to get 10m away from the bike and do things properly every half hour or so.

This is where the sun compass comes in, if you know local solar time and have the proper scale on the dial for your latitude, you can keep moving just by keeping the shadow on the right time.

Walkers get stuck in Scotland because they need accuracy to account for their lack of range. A bike with 2 gallons of petrol will hit a road and get out so long as the rider uses his map. A walker with nothing but a Mars bar and a can of fizzy pop in their pack can't do a 50 mile detour without freezing to death, and will become more disoriented by the time it takes them to go round an obstruction. Of course a biker with a siezed engine is just a badly dressed hiker........

Andy

You can use the compass (and a map) to calculate waypoints of interesting places that’s not on the GPS-map.
The compass can also be used together with a GPS to figure out exactly where you are on the paper map.

Nice description there Andy. With Alloy bars, plastic fuel tanks etc the local magnetic attraction might be minimal on some bikes. In basic fiddling and experimentation I have found that the compass needle does not have to be very far from local metal to correctly indicate magnetic north.
Perhaps the bike influence on a compass needle is greater when the engine is running (with increased local magnetic field generation)?

As mentioned in another post, at least a compass can give you a rough indication of orientation of a map, no matter what the weather conditions are, day or night - however, I have still managed to get it wrong when tired/cold/basically knackered.


Dodger/henry,
I've tried out navigating by both the Pole star and the Southern Cross - they are both fine if you want to go North or South, but not so useful if you are aiming to go, say, SSE or NNW etc etc.

The bar is a really useful place to be!

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Dave

Absolutely right.....they need as you say, to be swung, or you can search around the h/bars for a neutral spot.....

I found this on my @ on top of the front brake reservoir....

Incidentally, I find that the compass is at its most useful in towns.......elsewhere, an approximate heading is sufficient, even if my compass is not spot on....