20-Function Bike Computer

I had no problem installing this unit. Took 2 minutes. First attach the sensor loosely with the tie straps on the fork so you can slide it up and down, attach the magnet, then slide both up and down until they're 1mm apart (note the arrow on the sensor). Tighten the straps on the sensor, and tighten the screw on the magnet. I don't know how it could be easier!I will say, the instructions are lacking a bit. I know they want to sell this for cheap, so the instructions are printed in about a 6 point font with 5 languages on 1 sheet of paper. So if you want to look up "How to reset trip odometer" it's not like you'll be looking in an index to find it. You have to scan the small print first.As to the function of the unit, it works GREAT. The software in this is very well done. There aren't any annoyances that I've found that you generally see in cheap electronic.To calibrate, you're supposed to enter the circumference of the tire in millimeters, and there's a little chart in the instructions that converts your wheel diameter to MM. However, I went a step further and actually measured how far 1 rotation of the wheel would take me. First I made sure the tires were inflated properly, then I put the valve stem at the low point of the wheel aligned with a crack in the sidewalk. I then walked the bike (while sitting on it) for 4 rotations of the wheel, and measured the distance, divided by the number of rotations and converted to millimeters. I found my measurement to be to be about 3% smaller than the chart, probably due to the tire compressing under the bike and body weight.**UPDATE**After using it for a while, however, the computer didn't really "click" into the holder very well, and I've had it fall out a number of times while riding and hitting some bumps. Still works, though, but something I need to be aware of. Since I've gotten this unit, I've tracked my rides with my smartphone and one of the free mapping apps out there, but I still use the computer to give me an overall distance and speed so I don't have to look at my phone while riding.

Time of use: 2 months~350 milesOverall opinion: a strong value.As many others ave noted, this unit provides many functions of much more expensive computers, but does so for a very reasonable price, and it does so while providing reasonably trust-worthy accuracy.In terms of accuracy, I have tested the:--milage/speed MXS/AVS functions and found them to be accurate when the proper tire diameter is entered.--air temperature accuracy seems to to be suseptable to wind chill - the faster you ride, the lower the reading drifts. This can be corrected for somewhat by blocking (protecting) the front of the computer and mount. In my case by moving my front reflector in front of the computer, about 3/4 inch. This reduced the windchill notably and resulted in resdings within a few percent of actual temperatures.--calories/fat calories burned. Accuracy knknown. In my case this is mounted on a mountain bike, and based on all the PC software calorie counters I use, this computer reads lower than actual calories burned. This computer appears to use a simple time/distance algorithm based on closed corse/rider weight/road bikes (smooth/slick tires @ 80~130 PSI) to cacluate calories burned. The computere does not offer options to compensate for treaded (knobby) tires at low pressures, course incline, riding surface (sand/dirt/paved etc) wind speed-direction etc....but for the price, I dont mind one bit and I suspect the readings are faily accurate if used on a road bike with standard 30 inch tires.As for the instructions, they are fairly straight forward and easy to use/understand but they do leave a little something to be desired as they are printed in the now-a-days all too common micro-script so they can all be fit on 1 sheet. As such they are a little difficult to read, but otherwise I found no note worthy problems.All that said, this computer does have a problem or two as others have noted. Mine computer, like other users, ceased functioning not too long after installation, however this was a fuction of maintenance, not of design or manufacturing flaws, and was/is easy to resolve.The problem is with the computer/mount contacts. The contacts on the mount are molded in place while the contacts on the compuer are spring loaded, but the springs are of very low pressure. Both sets of contacts appear to be plated, either in chrome or nickel. The plating is definately of good quality and resists corrosion very well. Between the rain, auto exaust, my sweat and the pollution put out by the nearby oil refineries and paper mills, my computer has been drenched in all kinds nastiness and salt water, but the contacts show no sign of corrosion. That said, while the contacts resist corrosion, they are suseptable to film build up (pollutants, road grime, what-have you) which the low pressure springs on the computer contacts cannot overcome, causing a loss of signal to the computer from the sensor. This film build up is easily removed though, with a few gentle swipes (did I specify gentle?) of 000 steel wool which restores the computer to perfect function. 000 steel wool is cheaply available at most hardware stores but BEWARE!!!! DO NOT USE the coarse stuff you would use in the kitchen...Brillo pads, scotch brite, etc...and do not apply too much pressure...you risk removing the plating.So, in my opinion, if you want an inexpensive, reasonably trouble free, good general usage bike computer, this unit is a strong contender.