I was all set to put one of my unused bike computers on my Coker today. I took one look at the spokes and realized that the Coker spokes are way to thick for the magnet made for mounting on a standard bike spoke.
Which computers work with the Coker wheel?
Acually, the magnet is not anything special. You can attach almost any of the small magnets in any way, glue, widen the slot on the one you have, make your own mount, anything that gets the magnet close enough to the pick-up, which is just a reed switch. And it needn’t be on the spoke, glued to the rim is also ok, as long as you can get the pick-up and magnet close enough.
I’ve got three pickups and two magnets (one pick-up is on another wheel) on my Windcheetah (a trike) - one for the good display, one for a Palm Pilot for recording the trip, and one for cadence.
I’ve even seen bike computers used on motorcycles as most speedometers (even on your car) have really bad accruacy problems. And the spokes on mototrcycles are really large.
The trick with cycle computers on a Coker is finding a computer that can be calibrated for a wheel that large. Not all computers will let you input a Coker size wheel.
Calibration will be somewhere between 2770 mm and 2850 mm. It depends on your weight, tire pressure and tire wear. I use 2775 mm for my Coker. You’ll want to do a roll out and measure the distance for yourself if you’re concerned about accuracy.
If you’re looking for an inexpensive option I just saw a Schwinn computer at Walmart for $9.32 (USD). I’ve been using a Schwinn computer on my Coker. Mine says “Sting Ray” on it and the one at Walmart says “Schwinn”, but it’s the same computer, same specs. It will allow you to set a wheel circumference from 0mm to 3999mm (That’s plenty for the Coker). The magnet will fit the Coker spokes. I can’t remember if I had to file or modify the magnet to get it to fit, but I don’t think I had to do anything. And it’s a Schwinn, you can’t get more retro style than that. One nice feature is that it registers speed in 0.1 Km/Mile increments. Some other computers only go in 0.5 Km/Mile increments or 1.0 Km/Mile increments.
But if you’re just looking for a magnet that you can use with one of your existing computers, ask at your local bike shop if they have any magnets that would work or if they can get you a magnet that will work. There are special magnets available for bladed spokes, composite wheels, and other non-standard wheels. They should be able to get you something that will work with the Coker.
Brian and John, thank you for the tips.
I think I’ll try the Wal-Mart option you suggested John, thanks.
Re: Computers on Cokers
On Sun, 15 Jun 2003 02:31:52 -0500, john_childs
<john_childs.p20oz@timelimit.unicyclist.com> wrote:
>The trick with cycle computers on a Coker is finding a computer that can
>be calibrated for a wheel that large. Not all computers will let you
>input a Coker size wheel.
In that case it might (just might) be possible to use two magnets and
enter 50% of the rollout value.
Klaas Bil - Newsgroup Addict
“661, neighbourhood of the Beast”
Re: Re: Computers on Cokers
Yes, that should work quite well, or if neccessary 3, 4 . . .
Well, I struck out at my local Wal-Mart. All they had was a Bell brand with a ridiculous design, a $20 price tag and a range of a 20" to 27" wheel. I checked out a bike store as well but nothing that would take the numbers needed to calibrate the big wheel. I don’t mind paying for it, I just want one that will work with a minimum of hassle. My quest continues.
I’ve been using a Cateye Enduro 2 on mine for a couple of years now with no problem. It will calibrate for the large wheel size, and the magnet fit the spokes with no mods. Bought it from one of the online bike shops, but really don’t remember which one, but i do remember that they were available from quite a few different sources…i just ordered from the one with the best price.
Chuck
Re: Re: Computers on Cokers
Has anyone actually tried that? I don’t think you can get the two magnets 180 degrees apart. The spoke crossing pattern really messes it up. If you take two spokes that are opposite each other on the rim and put a magnet on those two spokes, the magnets would not be 180 degrees apart due to the spoke crossing pattern. If the wheel was radially laced it might work, but with a 3 cross or 4 cross pattern it’s not going to work.
I had two magnets on a coker mounted on almost opposite spokes, the slight offset doesn’t make any difference to the avg. / max speeds recorded in my experience.
Joe
Re: Computers on Cokers
John, I disagree that it is not possible to get the magnets 180 degrees
apart. All of the computer magnets I have used are designed to be mounted to
two spokes above or below where the spokes cross each other. A 3 or 4 cross
wheel will allow for two magnets to be 180 degrees apart.
Rick Eppley
“john_childs” <john_childs.p3khb@timelimit.unicyclist.com> wrote in message
news:john_childs.p3khb@timelimit.unicyclist.com…
>
> Klaas Bil wrote:
> > On Sun, 15 Jun 2003 02:31:52 -0500, john_childs
> >
> >[color=darkred]
> > > <john_childs.p20oz@timelimit.unicyclist.com> wrote:
> > > The trick with cycle computers on a Coker is finding a computer that
> > > can be calibrated for a wheel that large. Not all computers will
> > > let you input a Coker size wheel.
> > In that case it might (just might) be possible to use two magnets and
> > enter 50% of the rollout value.
> >
> > Klaas Bil - Newsgroup Addict
> >
>
> Has anyone actually tried that? I don’t think you can get the two
> magnets 180 degrees apart. The spoke crossing pattern really messes it
> up. If you take two spokes that are opposite each other on the rim and
> put a magnet on those two spokes, the magnets would not be 180 degrees
> apart due to the spoke crossing pattern. If the wheel was radially
> laced it might work, but with a 3 cross or 4 cross pattern it’s not
> going to work.
>
>
> –
> john_childs - Guinness Mojo
>
> john_childs (at) hotmail (dot) com
> ------------------------------------------------------------------------
> john_childs’s Profile: http://www.unicyclist.com/profile/449
> View this thread: http://www.unicyclist.com/thread/25753
>[/color]
There is no reason that the 2 magnets would have to be 180 degrees apart, as long as there was a decent seperation between them. Unless you wanted your total distance to be really accurate!
Re: Computers on Cokers
In article <uni.wobbler.p4d6n@timelimit.unicyclist.com>,
uni.wobbler <uni.wobbler.p4d6n@timelimit.unicyclist.com> wrote:
)
)There is no reason that the 2 magnets would have to be 180 degrees
)apart, as long as there was a decent seperation between them. Unless
)you wanted your total distance to be really accurate!
Your distance would be correct whether or not they’re perfectly aligned;
it is your max speed, and your momentary speed, which would be slightly
off.
-Tom
Re: Re: Computers on Cokers
They have to be the same distance out from the hub and
Unfortunately as on a 3 cross 36 spoke wheel, spokes are in sets of 4, and 36 divided by 4 is 9 (ie. not even) the point at which you’d need to attach the magnet at the opposite side of the wheel is halfway between two spokes. You might be able to do something with single spoke attachment magnets to get them a bit better, but otherwise you’re stuck.
The only reason to worry about magnets not being 180 degrees apart is because some older bike computers use a single magnet pass to calculate max speed without taking an average of several readings, so you’ll get a slightly too high top speed.
Joe
I use the Enduro II also and it works great. It handles the proper wheel dimensions.
I use the polar S710 on both my MUni and Coker, and it is great. Great software and there magnet fit’s just fine. I got mine on Ebay for pretty cheap. Enjoy.
Couldn’t you take one of those reflectors that clips across two or more spokes, dremel a hole, and glue the magnet into the reflector? That way, it would be halfway between two spokes.
I used to use a Cateye Mity II on my Coker. It was programable to the Coker size wheel and the magnet fit the Coker spoke easily.
Mojoe
Now that is pretty hardcore. Those are about £150 here. Do you actually use the software much, are you doing serious training with it or something?
Joe
Re: Computers on Cokers
On Mon, 16 Jun 2003 10:18:43 -0500, joemarshall
<joemarshall.p4h4b@timelimit.unicyclist.com> wrote:
>The only reason to worry about magnets not being 180 degrees apart is
>because some older bike computers use a single magnet pass to calculate
>max speed without taking an average of several readings, so you’ll get a
>slightly too high top speed.
You would also have that disadvantage if the computer averages a
number of readings that is not a multiple of the number of magnets
used.
Klaas Bil - Newsgroup Addict
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