Speedometer problem
 

Hi folks,

I bought a speedometer (search CAT EYE - Velo 8 Cycle Computer, Black on Amazon, I'm not allowed to include urls for some reason) for my son's bike, a Jamis TrailX. It's a cheap chinese speedometer, but I wasn't looking to spend lots on it. The instructions are poor but seem to indicate that the magnet on the wheel has to be ~5MM from the 'reader' that gets attached to the forks.

The bike is such that the forks are far enough away that it doesn't get anywhere close to 5MM away. I have a pair of digital calipers and I think it showed they were 23MM away.

Any suggestions for a not too complex fix? I don't want to spend a great deal of time on it or hack something together that won't last so if there are no options and instead, there is a recommendation for a not too expensive speedometer that will work out of the box, I'd happily take that too.

Thanks in advance.

Nathan

How far away down by the axle?
How far away when the reed switch & magnet are actually mounted?

I imagine you used all the wire you could to get it closer to the hub and closer to the spokes.

You can get something like a block of hard rubber, maybe a plug from a hardware store, and some exterior double stick tape. Cut it to size, stick it on the fork and then zip tie the sensor and rubber block to the fork.

John

It's not much closer down by the hub. Any chance you can link to what you mean in terms of a rubber block at home depot? I checked their website and didn't see anything.

23mm is a 7/8” gap. I can’t imagine a front hub being that far away from a fork.

It doesn’t have to be a piece of rubber, it can be a square plastic Or aluminum tube. The idea is to push the sensor away from the inside surface of the fork And use it as a base for the sensor. Heavy duty double stick tape will keep it in place and the zip ties will fasten it.

Usually when I’m faced with this type of stuff, I figure out what shape/material I think will work and then just go to the hardware store. I might see something in plumbing or electrical and go from there.

John

All godd suggestions. Spacer block and placement on blade where spokes are closest. Also which side of fork is used can be in play as with dished (disk reasons) ft wheels. But the spacer under the sensor is the time proved way. Andy

If you've got an old inner tube, cut it into pieces about 1" x 0.5". Stack them up (use some electrical tape to hold them together), then zip tie the sensor over the stack on the fork. Ugly but functional.

FWIW, I can usually get the speedometer to pick up the signal when the magnet is within about half an inch of the reed switch.

Maybe by moving the sensor pickup to the rear wheel and the sensor to the frame arm, it will be closer and cure your problem

Yeah, it might but the connecting wire won't reach the handlebars. You could mount the head on the top tube but then you have to read it sideways. :rolleyes:

Joking aside, years ago I did just that to mount a cyclometer on my indoor trainer bike since I needed a rear wheel pickup. Awkward but functional and the distraction of reading it wasn't a problem since I wasn't going anywhere. Cat-Eye did sell a cyclometer (the Astrale) with a long connecting wire that allowed rear wheel magnet and chainstay sensor mounting but they are no longer offered.

And not all magnets included with computers are them same. If your computer has a weaker magnet you could find a rare earth button magnet and stick it to the supplied magnet (maybe with a drop of superglue for insurance) it would increase your range significantly.

There is no magnet anywhere that will work from 23 mm away.

You have to jury rig like suggested above.
For that type I also bought larger 1" magnets to allow larger clearance. All looks weird and will give trouble. You got what you paid for.

Get a cheap GPS speedometer. Or a wireless type with accelerometer that attaches to the hub.

No, those Cat-Eyes are reliable, accurate and sturdy. The problem is with the OP's bike and it's fork configuration or with where on the fork he has mounted the pickup. Properly set up the cyclometer will work very well.

I've had those wired magnetic sensors on at least 3 bikes and all required some buildup to bring the sensor close enough to the magnet. For cadence sensors I had to buy larger magnets. And that isn't a long term reliable solution. Not even mentioning the wire that will break some time. You just have to spend a bit more and get GPS or accelerator sensors. They work on any bike or fork. Go with the times, there is better technology in 2020. No one has to take my advice. You are entitled to learn it the hard way.

For unique applications I fully agree with the suggestion of wireless and GPS/accelerator systems. But there are many of us who don't with to have to deal with this current level of technology to ride their bikes. When I was touring across the country I did have a Spot Tracker, at the request of the wife. But for regional day riding my flip phone stays off and my Cat Eye Micro is on. Andy

OK, I guess learning the hard way means I have to forget >230,000 miles of riding over 35 years and all of it using wired cyclometers, the vast majority being Cat-Eyes. I currently have them on four bikes , two with over 50,000 miles each, and have never needed to "build up" the pickup mount or the magnet on any bike. Now, what improvement can I expect from "better technology"?

"better technology" provide more data and the ability to produce stats via apps, oh and the ability to brag when on the various social media platforms that this "better technology" is associated with. But the basic issue of speed, distance and time won't change. Andy

Sure, except I really don't have anyone to brag to and the data wouldn't support much bragging even if somebody would listen. :50: As you note, the plain statistics of speed, distance and time are all I care about and that's only of interest to me. "Social Media" are what my kids and grandkids do, not me.

GPS can be useful when I'm not sure where I'm going but that's not often.

Nathan, could you post a photo?
often it's common to skooch down the magnet as far down as you can, and or also to simply turn the sensor inwards a bit to get it physically closer to the magnet. I have done this on one of my bikes at least and it works perfectly. Tightened properly with some rubber underneath that helps stop it shifting works well, and once in a very blue moon if it gets bumped being put into a car or something, you just reposition it.

Hi all, thank you for your suggestions for a beginner. I was able to find a spot lower down on the front wheel where the magnet was close enough to sensor to make it work. And, I was able to figure out how to program the wheel size into the speedometer even though it was not a standard wheel size. Went out yesterday with my son who has a speedometer and we compared distances and speeds and were A-ok.
Thanks all!

Nathan

Im a touring guy, so put practical stuff first.
Unlike you, have never had to buildup sensor before.
never had to buy stronger magnets
maybe had a bike computer have something break, but after years and years and years of use.

of course gps units are cool, but they also eat batteries.
they also cost a lot more...lots and lots

so for this touring dude, a simple, inexpensive bike computer that the battery will last a season easily, no recharging etc, no fading battery life over the years, no obsolescence coming into play---but shows the basics I need.

sure, I cant do turn by turn riding, but frankly, for the touring I do, I dont need it 95% of the time, and I'll use the 200, 300, 400, 500 bucks I didnt spend on touring stuff or many many daily budgets for a fun trip that Im enjoying myself and plodding along at 15kph average on my touring bike.

and I too dont give a rats patooty about very detailed stats and all that, although I totally get being into that. I ride fast sometimes too and push myself, a big part of it is money--I just dont see the priority of an expensive gps unit.

Since this for the OP’s son, and a cycling app was not part of the discussion, I am under the impression that the object is just basic data on an entry level bike.

Based on how tech savvy kids are...

John