Sunding SD-558A speedometer

jolfstn

Member
Oct 30, 2011
112
1
18
Seattle, WA
Though I would rather an analog dial type speedometer the cables & wheel hardware don't last on my 1985 Fat City Cycles mountain bike with mag wheels & 66cc 2 stroke HT Engine from Bicycle Motor Works. I purchased this digital cycle computer from eBay for $10 including shipping. Seller is no longer selling these, however there are many more on eBay, and if you're more patient than I am, if you buy them from China they cost even less!
It looks like the Trail-Tech that sells on JNM Motors for $127, though Doesn't have the same features. The wheel magnet is designed to screw onto a spoke, so in order to attach it to my aluminum spokeless mag-wheels I had to drill a pilot hole for the tension screw then Gorilla glued it in place. Other than that installation was pretty straightforward. They included lots of hardware for various installation configurations. Once it's on, setup gives you a choice of metric or standard units, the clock has a 12 or 24 hour format, then enter wheel size and you're ready to go!
Speedometer gives fast accurate readings as compared to GPS for comparison and the screen is large & easy to read & includes a backlight for night use. Lots of trip odometer and average & Max speed settings and other features I have yet to use. Even displays the temperature! I couldn't ask for much more for $7+$3 shipping. Arrived in 3 days. here's the English page for the item from the manufacturer
sunding.com/en/plus/view.php?aid=29
My experience thus far with this cheapo speedometer has been great, anyone else have a particular model they've had good (or bad) experience with? What about those dial type analog mechanical models, the part that attaches to the wheel breaks quickly in my experience, or the cable snaps, which is a shame because this type aesthetically looks much better on a 2 stroke. I think the longest I had one last was maybe 12 miles. My next question is has anyone found a way to fortify them to last?
 

jolfstn

Member
Oct 30, 2011
112
1
18
Seattle, WA
Reading through the forum I've found a few instances of issues with interference & bad readings on digital speedometers with running engines. I just wanted to add that I've experienced no interference from my engine with this speedometer
 

Loop

Active Member
May 27, 2020
124
72
28
46
S.Knoxville
I’ve tried three Sundig speedos, they seem nice but the vibration caused them to reset, as for magnet there is a valve mount one on eBay for $3 I have one on order I’m going to try one last time to make the sundig one work then I’m going to use my phone lol.
 
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EZL

Well-Known Member
May 13, 2016
307
597
93
Chenoa, Illinois, USA
I’ve tried three Sundig speedos, they seem nice but the vibration caused them to reset, as for magnet there is a valve mount one on eBay for $3 I have one on order I’m going to try one last time to make the sundig one work then I’m going to use my phone lol.
I ruined an old analog MPH speedometer on the 212cc bike and trying to find another one wasn't working. I ended up going with
a more expensive GPS digital speedometer. There are no sensors to add for the IGS130-IGPSPORT unit. I've had it for a year
now and the only thing I found was the 212cc will accelerate fast enough that the GPS has to have time to register the speed.
The unit is back lit for night driving and turns off on daylight. I checked a analog speedometer with it that registers KMH and
found the analog was accurate on another bike. This one is expensive but is worth it just make sure to order a better mount
for it so you can remove it so it won't get stolen. I got mine on sale off of Ebay and the mount was high priced but was also
worth it.
 

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Loop

Active Member
May 27, 2020
124
72
28
46
S.Knoxville
Yeah I went with a gps model as well, I discovered that the resetting wasn’t the vibration but the engine itself, it’s realllllly electrically noisy and interferes with the little cheap speedometers.
 
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EZL

Well-Known Member
May 13, 2016
307
597
93
Chenoa, Illinois, USA
Yeah I went with a gps model as well, I discovered that the resetting wasn’t the vibration but the engine itself, it’s realllllly electrically noisy and interferes with the little cheap speedometers.
I had the best luck on the analog ones which has the mechanical pickup which uses a small pickup on the spokes which
drive a cable to the speedometer. Forget about the magnetic sensor magnet type they never did work worth a darn.
The expensive GPS speedometers are the way to go! (^)