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Suitable cycle speedometers

bruce morgans

Joined: 21-01-05

Topics: 6

Replies: 18

Posted: Wed 10th Aug 2011, 6:26pm
Suitable cycle speedometers

I'm sure someone in the past recommended a speedo that could be used on small wheels but I can't find reference to it. Can anyone help. I have a Sigma Sport BC500 which is fine but I don't think they are available anymore.
 

Replies To This Post

colinedmondson

Joined: 9-08-09

Topics: 3

Replies: 82

Posted: Wed 10th Aug 2011, 7:32pm

Hello Bruce. You are correct in thinking this topic was covered a while ago. My contribution was the £10 cheapy from Halfords, which can be set for 6" wheels and probably smaller, and doesn't want to tell you how many calories you have burnt and what you had for breakfast. I have only just run my loco for the first time and can't yet report on its accuracy. Hope this helps, Colin High Legh Railway
 

georgecoles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Thu 11th Aug 2011, 7:44am

I recently fitted a Halford's Value 5 Function Cycle Computer (cost £8.75) to our son's tram engine, which has 4.5" diameter wheels. It seems to produce the right results! I fitted the sender to a length of bike spoke fitted through a cross drilled hole on the axle. The sensor is clamped to a conveniently fitted bolt (standing in as a bike fork.)
These things count revolutions, and then do the sums based on the wheel diameter (which you input) so there should be no probs wherever you fit the sender/sensor in theory.
Hope this helps, as I can't give you any input on the one you have, but I would have expected it to work the same way, so it should only be a matter of calibration (i.e. telling the computer what size wheel you are using.)
Incidentally, we find a slight (noticable but not significant) delay in the readings, but presume this is the software doing its sums.
George
The GeoDor Railway
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Thu 11th Aug 2011, 12:52pm

One interesting feature that I discovered recently with my "cheapy" Halfords one, was when the battery ran out I cursed, thinking I should have noted the readings the last time I used it, but no problem, it picked up aparently, exactly where it left off, when I fitted the new one.
 

jimnolan

Joined: 1-01-95

Topics: 1

Replies: 3

Posted: Fri 12th Aug 2011, 11:23am

I know the offers are area specific but lidles are selling a wireless one at the moment for £6.99
 

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Fri 12th Aug 2011, 2:12pm

I wrote a small piece about this topic some time ago in the NEWS. The main criterion is that the speedo must be capable of being programmed down to suit our small diameter wheels. Some speedos are restricted to larger cycle wheel diameters, presumably because they assume that's all they will be needed for.
 

brianremnant

Joined: 6-08-07

Topics: 0

Replies: 2

Posted: Mon 22nd Aug 2011, 7:58pm

You can fool a speedo into thinking it has a large wheel by fitting an extra magnet,and it works i did it on my loco,i think i read about it in this forum some time ago.
 

colinedmondson

Joined: 9-08-09

Topics: 3

Replies: 82

Posted: Sat 27th Aug 2011, 7:18pm

Beware when fitting the Halfords one. Mine reads twice the speed I am doing, as far as I can tell. Only thing that comes to mind is that the sensor head has 2 pickups, and I have mounted my sensor at 90 degrees to how it would be on the bike wheel. My guess is that it is now picking up 2 pulses per revoloution instead of just 1. Gap between wheel and sprocket is just not big enough, so may have to mount somewhere else (or try telling it that I have 12" wheels!).
 

georgecoles

Joined: 4-08-09

Topics: 19

Replies: 90

Posted: Sun 28th Aug 2011, 4:28pm

Colin. I think you mean 3" wheels, if it is doubling your speed (assuming you actually have 6" rather than 24" wheels ;))
George
 

colinedmondson

Joined: 9-08-09

Topics: 3

Replies: 82

Posted: Wed 31st Aug 2011, 7:56pm

Thanks George, good point! It is either that or bend the wire so that it is oriented correctly, but of course the gap between the wheel and the sprocket isn't big enough. I have used taperlocks, so I can move the sprockets, but then the ptfe wear pads will have to move etc etc.
 

bruce morgans

Joined: 21-01-05

Topics: 6

Replies: 18

Posted: Mon 12th Sep 2011, 4:26pm

Hi Thanks for all your comments. The Halfords Value 5 works well and is steal at £8.

Regards Bruce
 
 
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