DailyTech - Garmin Delays Two GPS Models Designed for Cyclists

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Blog: Gadgets Garmin Delays Two GPS Models Designed for Cyclists
Michael Hoffman (Blog) - October 29, 2007 7:40 AM

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8 comment(s) - last by 16nm.. on Oct 31 at 10:28 AM

Garmin Edge 705 (Source: Garmin)

The Edge 605 and Edge 705 GPS units are for all of the crazy cyclists out there

Most people tend to think about GPS units in cars or motorcycles, but Garmin and other GPS manufacturers are willing to cater to a growing sports community that is willing to spend money on high-tech gadgets. The relationship between the athletic community and manufacturers is usually friendly, with the companies showing up at expos and races to promote their latest products.

One of the biggest problems that develops is when a product is delayed - and it has happened again. Cyclists wanting a shiny toy will be disappointed to hear that two of the most anticipated cycling GPS products for this holiday season have been delayed at least one month.

According to an article published on GPS Lodge, the Garmin Edge 605 and Edge 705 GPS units will be delayed from their expected December launch date to the first quarter of the new year. Considering Garmin and other tech manufacturers partially rely on the Christmas holiday season to help boost sales, the delayed launch will likely irritate some consumers. As a technology enthusiast who is willing to wait patiently for a better product, it is still disappointing to see a product be delayed until after the holidays.

Most people are familiar with the type of features consumers receive when purchasing a GPS unit for the car, but GPS products for cyclists have a few extra features that are not needed in other situations. To accompany the expected the GPS, heart rate and cadence capabilities, both the 605 and 705 allow cyclists to wirelessly share saved rides and workout information with others. The 705 also allows cyclists to see their power output -- measured in watts -- displayed directly on the screen, which I think is especially cool.

The Edge 605 will retail with a $430 price tag, while the Edge 705 will retail for $540. The Edge 705 GPS unit remains on my wishlist of tech toys I want to own in 2008.

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Interesting

By masher2

(blog) on 10/29/2007 2:27:29 PM , Rating: 2

quote:
The 705 also allows cyclists to see their power output -- measured in watts -- displayed directly on the screen...

I'd be interested in knowing what algorithm they're using for this, since your power output on a level surface is zero, except for losses.

Since those losses are going to vary by bike, current gear ratio, windspeed and resistance, and a whole host of other factors (none of which I can see this unit directly measuring), I think the number they display is going to be more of a guess than a hard figure.

RE: Interesting

By Andrew Campbell

(blog) on 10/29/2007 4:50:41 PM , Rating: 2

I think any serious cyclist tell you that power output on a level surface is not zero! You are fighting wind, tire deformation, and inertia if accelerating.

The way most power meters work is to measure physical strain in either the bottom bracket or rear hub. They also measure speed and cadence.

The algorithm combines this data with user provided information such as weight, tire size and pressure. Essentially I think the computer is measuring the rate of work done to the frame, based on strain.

There is one computer that measures speed, cadence, inertia and wind pressure. The iBike considerably cheaper and easier to use than the strain measuring models.

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RE: Interesting

By masher2

(blog) on 10/29/2007 5:37:10 PM , Rating: 2

quote:
The way most power meters work is to measure physical strain in either the bottom bracket or rear hub. They also measure speed and cadence

Does this unit do that though? I assumed it was simply using the GPS function to calculate speed (and possibly route slope) and from that, a rough guess at power output.

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RE: Interesting

By Andrew Campbell

(blog) on 10/29/2007 7:42:22 PM , Rating: 2

I believe they are saying you must use a third party power meter. The 705 will read the wireless signal, implement the algorithm appropriate to the specific model, and display the power.

This avoids the need to have two computers on the handle bars.

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RE: Interesting

By aeroengineer1 on 10/29/2007 8:06:22 PM , Rating: 2

If it is like their previous unit, it is not a direct measurement, though to be honest a direct measurement is not really necessary. There is only one unit that I know of, though I am sure that there are probably more, that takes a direct measurement using a strain gauge type setup. These units use averages of predicted data of weight and heart rate as well as age and a few other considerations. These give the rider a good estimate of power consumption. Unfortunately power output is not unnecessarily the most useful measure of energy as there is a body energy efficiency factor which relates the output to the input. This is even harder to measure, and is typically only done in a laboratory setting. A further problem with this is that this efficiency can change dramatically from day to day depending on the bodies condition. Things such as stress and sickness can effect this. In the end, the reference value is a pretty good estimate for the body considered to be fit for an open air condition. I imagine that it would be wildly inaccurate for a streamliner bike which can go 60-70 mph using the same amount of energy that a person would use going 30 mph on a road bike.

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RE: Interesting

By 16nm on 10/31/2007 10:28:09 AM , Rating: 2

quote:
The way most power meters work is to measure physical strain in either the bottom bracket or rear hub. They also measure speed and cadence.

I think you mean that the most common ones measure strain in either the crank or rear hub. The bottom bracket system was not a success and I think that company went out of business.

FYI, the more drive train you put between yourself and the power meter then the less accurate the system is. The rear hub method is the weakest system because you lose power in the entire drive train before power is measured, so you actually are putting out more power than the system indicates, and it always varies as your drivetrain wears and the lubricants dry/become contaminated. The strain guages in the crank system is the best because the only drive train components between your left leg and the strain guages are the bottom bracket and pedal bearing. The right leg only has one pedal bearing robbing power.

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705 Looks Good

By Andrew Campbell

(blog) on 10/29/2007 2:03:37 PM , Rating: 2

It's a shame the 705 will be delayed. The main reason I've been waiting to purchase a Garmin cycling computer is that I really need power more than gps to improve my training.

It appears that users will still need to purchase a third party power meter since the 705 will only read and display the device's output. So you can add an extra $1k to the price tag to get power. Ouch!

The heart rate, speed, cadence, and accurate elevation (this is extrapolated using a barometer on other non-gps devices) combined with route recording will make this a very complete package.

Delaying the product should not affect Garmin's business too much as Spring and Summer are their biggest seasons for sales.

Better Late Than Buggy

By NMR Guy on 10/29/2007 4:42:28 PM , Rating: 2

quote:
Considering Garmin and other tech manufacturers partially rely on the Christmas holiday season to help boost sales, the delayed launch will likely irritate some consumers.

Well, I'm sure it irritates Garmin as well :-) They will be losing sales during the most active sales time of the year. But props to them for not releasing a half-baked product. Really, it's better for everyone for them to release a quality product than one full of hardware or software bugs.

BTW, I own Garmin Forerunner 201 and 205 GPS units for runners. The 205 is great for finding new routes in the 12 -30 mile range, tracking your real time pace, etc. The 201's receiver isn't quite sensitive enough for some terrain.