Cycling UK Forum

Recommendations, please for a handlebar compass.

Am I correct to assume that Ti frames will not affect compass readings?

gbs

I use a Silva Sere 40 Watch Compass on my bike. They are available currently on on Amazon for about £7. Some outdoor shops also stock them but they can be hard find.

My hybrid has a steel frame and aluminum bars and the compass is not affected by the steel but on my all steel Brompton there is a serious problem so in fact I use the compass as designed on my watch strap. (Very useful when you come up from a London Underground station and have no idea which way you are facing).

Hope this helps

Alan

I didn't know Titanium frames didn't affect a compass, but your right I just checked with a silva compass. Compass does still go wonky if held close to the top of the steerer tube though.

http://www.bonthronebikes.co.uk/bell-compass (but cheaper from supemarkets etc)

But needs modification. The compass ball unscrews. Then removing the bell improves its sensitivity. The compass can then be screwed back in (and possibly glued). The mounting is a bit small but this can be bodged through the hole (eg with a cable tie).

It's not very accurate but as a sanity check its fine ( i.e the map says this road heads south and it does). But being there on the bars means you use it and its not hard to replace.

I did hear a story of a cyclist trying to use one to get out of a city. They stopped at each intersection and it said go right. And said this at each intersection. Apparently there was an electrical junction box on each corner.

You can buy compasses for cars - they used to be quite popular.
They are adjustable to nullify the magnetic variations from the car, so therefore they would work on a steel bicycle.

The same problem exists on steel-hulled ships with magnetic compasses.
Flinders' Bars and Kelvin's Balls sort them out!

http://en.wikipedia.org/wiki/Flinders_bar
http://en.wikipedia.org/wiki/Binnacle

I use a really cheap compass with flip cover - about 2 quid or less from camping shop. I keep it in the side pocket of my saddlepack or in my bumbag.

When I need it, I get it out. Check direction and can then usually put it away. I have never found I need to keep referring to it. Why bother with all the grief of a handlebar one. There is enough clutter there already. Plus breakage risk, of course.

You can't get much simpler than this compass.

Yes, it works on a ti bike - in fact it's the only bike I have been able to use it on. It must be mounted away from the brake cables though.

As Mick says, you can compensate for the metal in a bike but the effect it has on the compass varies according to which direction (in relation to the earths magnetic field) that your bike is pointing. Adjusting a ships compass is a complicated affair and needs a highly skilled compass adjuster or a lot of time from a reasonably competent marine navigator. Being one of the latter I would suggest that you would have a hard time adjusting a compass on a bike and would be better off accepting that the compass gave you a"rough" indication of the direction.

simonhill wrote:I use a really cheap compass with flip cover - about 2 quid or less from camping shop. I keep it in the side pocket of my saddlepack or in my bumbag.

When I need it, I get it out. Check direction and can then usually put it away. I have never found I need to keep referring to it. Why bother with all the grief of a handlebar one. There is enough clutter there already. Plus breakage risk, of course.

Agree really. I have one in the sidepocket of the barbag and just whip it out on the move, no problems with interference and can also use for daywalks etc.

The Mechanic wrote: ........ would be better off accepting that the compass gave you a"rough" indication of the direction.

Yep.
I take a Silva compass with me on tour.
You get to a road junction and not understand the layout.
You get your compass out and see which way is which.

I doubt a compass strapped to the 'bars would be far out of true. It would be "seduced" by the metal of a bike, but not so far out that you couldn't see north from northwest. Taken to the Nth degree, it should be possible to make corrections to get an accurate direction, but how much does it matter?

Apologies if this sounds a bit thick but can you disorientate a compass.I ask because on my Silva compass the red part of the needle seems to be directing me the opposite way to what it should.

hondated wrote:Apologies if this sounds a bit thick but can you disorientate a compass.I ask because on my Silva compass the red part of the needle seems to be directing me the opposite way to what it should.

Some years ago I took a very basic school lab type compass with me. Unfortunately the needle had been incorrectly polarised. I think you would have to be unlucky for this to happen to an already correctly polarised compass - but a good idea to check it before setting off.
As Mick F says it will only indicate an approximately correct direction- but useful nonetheless.

hondated wrote:Apologies if this sounds a bit thick but can you disorientate a compass.I ask because on my Silva compass the red part of the needle seems to be directing me the opposite way to what it should.

Perhaps you have the wrong idea about which end of your needle points north? I once had to ask my companions which end was north, white or red, in wintry conditions on the Glyders.
In any case, if red consistently points to the opposite direction then you merely need to relable it in your head.

Slightly off topic (but may be useful info for others) and that is that I bought a new Casio digital watch for my cycling (so I can leave the nice one at home), and the Casio has a built in compass function. You press a button and within 2-3 seconds, North and bearing are displayed. I've checked this against my Silva compass and it's good enough to use for bike navigation.

Prior to that I had a small Silva compass that tucked into the map bag that sat a-top my bar bag - if a reasonably accurate bearing was required, I did have to move it away from the steel frame, but for most purposes it worked well enough where it was.

And even further off topic (and certainly not a low-tech option) is that if you happen to have a smartphone (Android or iPhone), the compass apps have proved to be very accurate, but let's not debate the merits or otherwise of this one on this thread eh?

Couple of years ago I tried one of the Bell ones mentioned earlier. Did'nt take me too long to work out that on the handlebars it always pointed north regardless of actual direction.Still lying about in the shed so must have a search and start unscrewing to see if it actually does work. Easier than raking in the saddlebag for the Silva as extreme accuracy is not really needed.