# General Cycling Discussion - Need a speedometer for little wheels

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jump
10-22-03, 03:28 AM
Hey all, remember me? heheh. So I got a gas scooter just tonight off ebay and I'm lookin for a speedometer that will work with it's little wheels with only 80cm circumference (10in tall). Something must be around, anybody have an idea? I don't want to share my cyclocomputer on my bike with my scooter - it only goes down to a 100cm wheel size and I wouldn't want to mix my gas and bike miles anyways. Any finds?

Don't take me wrong ... this scooter is never going to come close to replacing my bike. I love biking. I thought this scooter was cool so I got it. And I can fold it up, stuff it in a locker or something at school, and take it home (if I'm lucky, it's not very compact). Plus I can take it to work without getting all smelly. I don't mind getting smelly when I'm on my bike, but I bet the boss would when I arrive!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11329&item=3631886176

Thanks all!

sch
10-22-03, 11:07 AM
One simple solution would be to mount two magnets on the wheel, this would double pulse the computer and make it think the wheel was 2x as large, then
enter a multiplier for a wheel 2x the size of your wheel. Just tried it with my
road bike and speedo reads 6mph with one magnet, 12mph with two. Put the magnets 180 degrees apart on the wheel. Steve

Gojohnnygo.
10-22-03, 11:18 AM
This should work.
Accepts wheels with a circumference of 1 mm to 3999 mm or a diameter of .5 mm to 127 cm (50 inches). The wired model is often used for non-bicycle applications such as motorcycles, karts, mopeds, scooter, road equipment, etc
You can find it here. http://www.branfordbike.com/computer/comp5.html

DieselDan
10-22-03, 04:35 PM
Just roll out the wheels like a bike, then follow the directions to calabrate the computer.

jump
10-22-03, 05:11 PM
One simple solution would be to mount two magnets on the wheel, this would double pulse the computer and make it think the wheel was 2x as large, then
enter a multiplier for a wheel 2x the size of your wheel. Just tried it with my
road bike and speedo reads 6mph with one magnet, 12mph with two. Put the magnets 180 degrees apart on the wheel. Steve

lol ... no ... that would make it think that the wheels on the scooter has 1/2 the circumference. The ideal thing to do would have the speedometer pick up the magnet's field every other revolution, but that won't work unless I do some electronic work (and I don't want to cut up my probe). I could do that, but I'd end up with a permanent scootometer ... good thinking though ...

jump
10-22-03, 05:12 PM
Just roll out the wheels like a bike, then follow the directions to calabrate the computer.

The wheel's too small for the speedometer. Like, the 80mm circumference is beyond the lowest value of the cyclocomputer.

jump
10-22-03, 05:15 PM
This should work.
Accepts wheels with a circumference of 1 mm to 3999 mm or a diameter of .5 mm to 127 cm (50 inches). The wired model is often used for non-bicycle applications such as motorcycles, karts, mopeds, scooter, road equipment, etc
You can find it here. http://www.branfordbike.com/computer/comp5.html

Hey nice find! Thanks a lot!!

sch
10-22-03, 06:40 PM
[QUOTE=jump]lol ... no ... that would make it think that the wheels on the scooter has 1/2 the circumference. The ideal thing to do would have the speedometer pick up the magnet's field every other revolution, but that won't work unless I do some electronic work (and I don't want to cut up my probe). I could do that, but I'd end up with a permanent scootometer ... good thinking though ...[/QUOTE/]

Good thing I left physics for other endeavors.... Steve

JasBike
10-22-03, 08:38 PM
you could just set it for a tire size 2x as big and figure half the displayed MPH? would that work?

jump
10-24-03, 03:27 AM
That would probably work, but that Panoram computer looks like the ticket. Plus I don't want to use my bike's computer for this, so I'd be buying another computer anyway. Might as well get a Panoram.

Gojohnnygo.
10-24-03, 11:26 AM
That would probably work, but that Panoram computer looks like the ticket. Plus I don't want to use my bike's computer for this, so I'd be buying another computer anyway. Might as well get a Panoram.
[QUOTE]Don't forget about the Sigma sport BC800 it's about half the price of the Topeak Panoram. http://www.branfordbike.com/computer/comp3.html#item2

Dahon.Steve
10-24-03, 12:26 PM
I have the best answer. Get yourself the Garmin GPS and the handlebar mount. This will set you back \$175.00 bucks but the GPS will tell you the speed you're traveling plus a whole lot more. I use mine all the time when exploring the MTA system in New York City. I ride the tain all the way to the last stop and the GPS just takes me home!

jump
10-25-03, 01:56 PM
[QUOTE]Don't forget about the Sigma sport BC800 it's about half the price of the Topeak Panoram. http://www.branfordbike.com/computer/comp3.html#item2

Hey look at that one! It's worthy too ... not quite as dashboardy as the panoram, but 1/2 the price ... hmmmm ... got me thinkin now ...

jump
10-25-03, 01:58 PM
I have the best answer. Get yourself the Garmin GPS and the handlebar mount. This will set you back \$175.00 bucks but the GPS will tell you the speed you're traveling plus a whole lot more. I use mine all the time when exploring the MTA system in New York City. I ride the tain all the way to the last stop and the GPS just takes me home!

Never thought of GPS! That would be really cool. But 175 ... I think I'd have to save up for that if I ever were to get it ... chuck-ching ... but it's like a probless one and can be used anywhere ... and it's cool ... well its another way the feds can track me down, booooo.