SD 546C Bicycle Speedometer Bike Wireless Waterproof Odometer Cycle Computer with Digital LCD Display & Multi-Function with Backlight GOSTAR

I ordered this item as a replacement for the exact same model (SD-546C) I have had for a couple years. (The left button on the previous model began to work only sporadically then not at all but given the inexpensive price for great accuracy and and the basic functions I wanted, I decided to reorder.)This replacement arrived within two days as promised. I installed it this morning and rode my 31-mile Blue Ridge Parkway route to evaluate accuracy and performance. (The Blue Ridge Parkway has markers at every mile and I have nearly 100 31-mile trips on the Pky over the last two years to compare against for mileage accuracy. Like the previous SD-546C model, this unit performed perfectly. It DID NOT lose wheel rotations on the 30 MPH down hill runs which has been a problem with other similar brands and models. (If you want real accuracy you need to perform a "roll-out test" to determine the exact millimeter distance covered with each tire rotation but that, like installation, isn't difficult. My 700 X 25 tires require a "2108" setting rather than the chart recommended 2124 to reach real accuracy but this unit does it with the right setting.) I highly recommend this model if you can be satisfied with the functions listed.

No where in the description of this product could I find the range mentioned. Upon receiving the item, it indicated 2 feet was the maximum, and I have found that is a stretch. I wanted to use this on my rear wheel to keep track of indoor riding in the winter on a stationary frame. It still works for that, but the location that I had to mount the display to be in range of the sensor puts the display out of view while riding. For my purposes, I'll just have to check it when I get off the bike, but it would be nice if it had 3-4ft of range.

This sensor, to put it simply does not work. I followed all the trouble shooting instructions And batteries and still cant get any function other than time. the plastic zip ties snapped when trying to apply them...every single one which delayed installation... I would not recommend.

This is junk! First, instructions are poorly written but basic knowledge got it installed. Secondly, and most importantly, the operation is flawed. The read out NEVER turns off and you can’t turn it off. So it’s on until the battery dies.It does seem accurate but the basic functionality doesn’t work. I’m sending it back.

Really nice that the wheel size input (CIRC for this model) is in millimeters. You can pop over to any tire size calculator and input something like 0798 for 10" scooter tire. Just need to use epoxy to glue a tiny magnet to the rim.

It appears to be a good product, but it came up first in my search for a speedometer for a stationary bike. This is only for actual riding, outside. I had to return it as I couldn't use it, but still gave five stars.

Like someone mentioned before the snap ties break very easily also I have tried everything and I do not get a complete reading it was a waste of money I wouldn’t buy it

Zero Stars. Completely disappointed. Sensor does not work. Says it’s capable of 60cm (23”) away. Would not work. Followed the troubleshooting tree and bought new batteries ($11). Still did not work. No phone # to call. Do not buy.