Illgot

Mounting on the rear wheel could record a greater amount of tire slippage versus the front because the rear tire provides the tractive force.

Because of that your rear tire may give inaccurate readings when on skidding on wet/sandy roads or if you use a coaster brake.

​​​​​​btw, wireless may also encounter interference from bicycle lights. I have this issue and can not run my lights on certain frequencies because it causes my wireless computer to go haywire.

canklecat

I used a cheap wireless computer for awhile. Worked fine, but couldn't transfer ride data to Strava or other app/website. It was mostly useful for keeping track of my ride distance and time.

So I started using an iPhone 4s. Worked fine for speed, routes and elevation. But as the phone got older it wouldn't hold enough of a charge for a long ride, especially if I wanted to snap a few photos, check maps, etc.

Then I added an older Wahoo bike kit with ANT+ adapter for the phone, and dual speed/cadence sensors that used magnets on wheel/crank. Worked okay, but the cadence was often wildly erratic and it drained the old iPhone even faster. It wouldn't last a 50 mile ride, even if I turned off the display.

Then I got a newer Android phone with a largish all-day battery. Worked great with Strava or Wahoo Fitness. But I still wanted other data, especially heart rate and cadence.

So this year I got a couple of inexpensive XOSS G+ computers, the bare minimum in GPS capable computers. No navigation aids at all, but records routes accurately, along with its own barometric elevation sensor, temperature sensor, and is compatible with my older ANT+ only sensors, and newer Bluetooth/ANT+ sensors like the Wahoo Tickr, and several models of swappable function speed/cadence sensors that work on Earth induction rather than magnets. Nifty little doodad for the money.

On the down side for XOSS, since January this year support has been sketchy from the manufacturer and app developer -- presumably due to the coronavirus pandemic, which has hurt many China based companies. The US market XOSS G+ and app sold by Amazon seems to be available and working properly, but some international market customers have unresolved complaints.

There are other similar low cost bare bones GPS computers. Check Amazon's latest reviews and check Fakespot to evaluate the quality and legitimacy of those reviews. Until the coronavirus pandemic is under control it's likely we'll see some problems with tech support and distribution for many companies.

One more note: There's little or no significant difference in speed/times for Strava segments and entire rides, regardless of whether I'm using my cheap wireless dumb-computer, smartphone GPS only, or computer with its own GPS and/or speed sensor. Same with elevation estimates.

The most useful functions I get from the little XOSS G+ are:

• Heart rate: I set an alarm about 10 bpm below my maximum to notify me I'm about to redline. Usually happens only during extended periods standing to pedal, or sprints up short, steep hills. Mostly it helps me stay within my training goals, especially for longer zone 2 rides to remind me not to turn it into an interval or tempo session.
• Cadence. I found that slowing my cadence from my former 90 rpm to around 60-75 rpm reduced my tendency to redline on short, steep hills. Took awhile to adapt but it works for me. Having the cadence readily visible helps keep me in my training target, including when I still do some high cadence aerobic sessions. The cadence sensors weren't accurate with the iPhone and Wahoo ANT+ adapter, but are generally more accurate with the XOSS G+. Might be due to differences in transceiver sensitivity, range and resistance to RFI/EMI.

I don't really pay much attention to speed, even though it's the most visible data on the little screen. Too many variables -- wind, etc. -- to make speed alone useful data. If I get another, more expensive computer I'll want the option to make other data more readily visible -- heart rate, cadence. Maybe a simple navigation aid like a virtual compass (which the Bryton Rider 15 has).

HerrKaLeun

If HR would give reliable power data, no one would spend $ on a power meter.

The desired outcome is speed. No race has been won by measuring power. A rider's training goal is to get faster. Luckily speed is easily measured.

Same way a weight lifter measures how much weight he lifts and how often, which also determines winning. No power measurement needed.

Sure a crank power meter can help your coach analyzing to train for the TdF. But if you have time to be on a forum instead of training, you certainly are not on the TdF.

Chuckles1

Three bikes, all with inexpensive units with wireless speed sensors lashed to fork. Not sophisticated, but all I care about on the road is speed and distance. I'm happy to be wireless though.

Batstar

Ditto. My Cateye sensor is strapped to the inside of the fork so it’s not as visible. Recently moved the unit from the stem to a BarFly combo mount.

DJJonnyT

I have a Garmin Edge 1030. Cadence sensor on the left crank arm. Speed/Distance sensor on the rear hub but it could be on the front hub, or none at all for that matter, as the head unit will keep track via GPS. BUT... GPS signal can have issues on heavy tree lined trails so I prefer the speed distance sensor on the hubs of all thee of my bikes.

caloso

Garmin, which talks to the power meter in my crank, the hrm around my torso, and the satellites in orbit.

GamblerGORD53

ONLY a properly measured out wired computer is 99.8% accurate 99.9% of the time. So that's all I'm going to use. SIGMA 16.12 and lately with a 14.12 altimeter on my back wheel, that is wildly wrong. Not that I expected it wouldn't be.
GPS is a farce IMO. They are location accurate to what 50 feet?? LOL Multiply that a thousand times in a hundred mile ride.
One time I was playing around at home with free Map my Ride. I plotted the map to every corner on a mostly straight highway course. It was 8 miles off in 78 miles. PATHETIC. It seemed to be using it's own make believe routes.

nomadmax 

Sure there is, a front wheel speed sensor won't read when a bike is in a fluid/magnetic trainer where the front wheel is stationary.

spelger

GPS is better than that. 50 is probably what the gov permitted many years ago, it is not far more accurate...

https://www.gps.gov/systems/gps/performance/accuracy/

true, it does still have problems when in canyon like settings (cities/tall buildings/canyons). this should not be a surprise though.

by the way, my smart phone works really well with GPS, when i zoom in on a ride i can see my path on the right side of the road compared to off the cliff or on the wrong side. i can even see the return path on the correct side of the road as well. that is a testament to its accuracy.

njkayaker

Yes, that's one.

With both wheels present and turning, front and rear sensors work equally well.

Steve B.

Seems like a mind made up.

Consumer GPS is accurate to around 10 ft. That's for the initial fix, the error does not multiply over a ridden course. My vintage Garmin 810 was accurate to about 1-2 miles over a 100 mile route, but if you have weak signals and many multi-path errors, than a track can be pretty inaccurate and as spegler stated, canyons, tall buildings and deep woods cause the most problems. The newer models however all receive GPS, GLONASS and Galileo, so have improved accuracy. Then you can add a speed sensor that will provide precise speed, which reduces any error, effectively.. Many mt. bikers and roadies in road group rides use these to improve the distance accuracy as well the instantaneous speed reading.

Is a GPS more expensive than a Cateye wireless ?, certainly. But the Cateye isn't sending your ride data automatically to an on-line activity tracker, nor is it able to show you on a map, the neighborhood streets to route you around a detour, nor give you turn-by-turn directions on a route you've created in a place you've never ridden, or connect to assorted HR monitors, cadence sensors, power meters, nor give you elevation metrics, etc...Lots of useful functions on a GPS is why its what most cyclists tend to move towards.

Flip Flop Rider

Garmin gps, no wires

Illgot

GPS depends on having a clear signal and power. If either the signal or power gets interrupted or weakens then the readings can be easily thrown off.

wipekitty

I've got a very basic GPS (Bryton Rider 10). I use it for recording distance and elevation gain; I've also found the % grade measurements useful while riding. I've also found the capacity to pair with a HRM useful for things like interval training and making sure I don't overdo it in hot weather.

As a basic computer, this one does not have the ability to create, import, and view maps. If I'm in a new area, I'll use the (paid) RWGPS app to provide verbal cues, or just use oldschool paper cues.

BengalCat

Garmin Edge 1000 is the ticket for me. I actively use grade, HR, and cadence to dictate and measure effort and performance. HR and cadence aren't evaluated independently but usually as a tandem measurement. Other options and features available such as maps/navigation and the computer uses both GPS and GLONASS plus live Strava segments if desired. (Also controls mounted lights.)

spelger

i agree with you which is why I included the link. By the way, I meant to write “it is now far more accurate...”

bobwysiwyg

My estimate as well. Actually, the accuracy amazes me. Certainly good enough for government work.

Steve B.

In the early days, the government had dumbed down the consumer accuracy. I think it was Reagan allowed it for civilian use and Clinton decided to allow the same essential accuracy the military had.

WOW, just read that accuracy is now 11 inches. Still has signal strength issues though.