[Codejockey]

Being new to biking in general (at least from an adult perspective), I'm not really certain what a bike computer does for you. One question I have, is can I use my handheld GPS that I use for GeoCaching to assist me as a bike computer since it will track speed, distance, route, etc? Or are there features that a bike computer will have that are necessary for me to understand what I'm doing that my GPS won't offer. I should add that mine is a Garmin eTrex Summit HC gps unit.

[Industry_Hack]

Your GPS can be a great tool for tracking fitness, but it lacks two features that you may find useful. At the most basic level, you want to be able to track your average speed over a fixed route. That will let you see improvements made in your overall fitness. If you have a good 10-20 mile loop you can do once a week or so, you'll be more aware of incremental increases in your average speed.

Of course, a simple watch or clock could do that, which is where your GPS might be better, if it lets you review your speed over different legs of the course, such as a climb. If you really want to improve your fitness, you'll want a computer with cadence, to let you know how fast your legs are spinning, and a heart rate monitor, to keep track of your heart rate. This is not just for racers, or ultra-competitive weekend warriors. A good computer will allow you to find the optimum gear to maintain the correct cadence and heart rate, keeping you in an aerobic, rather than anaerobic state.

I'll stop now, in case I've gone way beyond your question.

[LarryM]

Originally Posted by Codejockey

One question I have, is can I use my handheld GPS that I use for GeoCaching to assist me as a bike computer since it will track speed, distance, route, etc? Or are there features that a bike computer will have that are necessary for me to understand what I'm doing that my GPS won't offer. I should add that mine is a Garmin eTrex Summit HC gps unit.

I think your eTrex Summit has all the functions of a basic bike computer. A basic bike computer provides the following info:

Current Speed
Overall Odometer - generally not reset, so it shows total miles since installation.
Time of day
The following easy to reset trip registers:

Trip Odometer
Trip Moving time
Trip Max Speed
Trip Mean Speed

.
The Trip Computer page of your eTrex Summit shows all of the same info except Time of Day, which, IIRC, is available on another eTrex page.

Some up scale bike computers can track elevation, which your eTrex also does.

Some up scale bike computers track trip Time/Speed/Distance for two separate trips, which is handy when following cue sheets with instructions given in terms of leg distances. The eTrex Summit can only track TSD for one trip at a time. You could reset the trip odometer at the start of every leg to get the same info, but then you would loose the trip average speed and such.

Some up scale bike computers track cadence. As Hack pointed, other bike specific GPS units can track cadence and heart rate, but the eTrex Summit does neither.

The eTrex Summit, along with most other GPS units, can record tracks and routes. Bike computers do not.

A really nice feature of the eTrex on a trip is that, if you loaded the Garmin maps, it can help you get unlost when the road names on the ground don't match the road names on the map.

On trips, but not generally on local rides, I use a eTrex Vista HCx with the Garmin maps. In addition to getting me unlost, I use it to find the nearest services ... things like campgrounds, hotels, restaurants, convenience stores, gas stations, or whatever. I've also used the mapping capability to find my way around detours.

[Edit]There are other features of the Garmin eTrex series GPS that a touring cyclist would find useful ... such as compass, time and distance to waypoints. Tracks and altitude profiles might be of interest to some.

[Codejockey]

Thanks for the indepth reply and comparison! It is really helpful. I think ultimately I might use both for long trips / touring, but until then it will suit my needs just fine. My wife has a Polar HRM watch that I can wear to monitor my heart rate, so the only key thing I'm missing is the cadence, but I will buy one (maybe for fathers day ). Anyway, I appreciate the info.

[Industry_Hack]

In all fairness, (especially if you have budget concerns) your knees and lungs will tell you when you're at the right cadence. Too low, your knees will ache. Too high, your lungs will burn.

[jagonz456]

buy a $40 computer and set it on your bike. I use a garmin GPS and it works great it gives me all the info i need to know. Once in a while i ride in deep country roads and GPS signal is weak and it drops. when this happens i am glad i purchased a regular wireless computer. GPS is great but doest work every where use the bike computer as a back up its worth the extra $40. The GPS always need to be charged the bike computer just works every time no fuss.

[craisin]

Ive got a rough moutain bike and the wires are ripped out of the computer i have attached them back on the instrument end am sure it doesnt matter what way round the are hooked up
if you know better tell me please

[sarahk]

Originally Posted by Codejockey

Being new to biking in general (at least from an adult perspective), I'm not really certain what a bike computer does for you.

Of the options discussed I'd go low tech on an mtb, and high tech on the road. Cadence isn't really an issue on gnarly single track

Originally Posted by Industry_Hack

If you really want to improve your fitness, you'll want a computer with cadence, to let you know how fast your legs are spinning

Originally Posted by Industry_Hack

In all fairness, (especially if you have budget concerns) your knees and lungs will tell you when you're at the right cadence. Too low, your knees will ache. Too high, your lungs will burn.

This is true once you know what your optimal cadence is, but when I started on the road my cadence would sit at about 50 or 60 which was fine for stonking up relatively short gravel hills out of the saddle but hopeless on an 80km Sunday ride. Now that I know what 90rpm feels like I'm able to ride at it without a computer but bad habits quickly return.

I would also recommend that the cadence be visible all the time as the other stats aren't really needed until the end of the ride. My latest computer is a cheapie but has cadence as the largest of the 4 stats always available and is excellent.

[1stthings1st]

I have seen these and think it would work fine. Something is better than nothing. Give it a try. Wish I had one.

[Grenouille]

got a computer a month ago, and love having it. If you can measure what you're doing, then you can work to make it faster. cant race against yourself if you dont know what you did last time

what can I say, i'm a CPA by daylight, having all that instant data on the bike is so compelling I have to force myself to look up and see where the bike is actually going, kinda like texting while driving a car.