Tom,

Please pay attention to the unit's accuracy over hilly terrain. I've had one for a bit over a month and only used it running, as my motorcycle's odometer is broken and not worth fixing, and I don't own any other forms of motorized transportation. Anyway, I suspect it sees the world as flat from above and only measures linear distance accurately, and that lacking an accurate altimeter it's not entirely useful on hilly terrain (such as we have here).

I've found it a fun toy, but not essential. I'm glad I got it at a great discount and not at the list price.

Look forward to your review on it.

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American's are definately infekting the world with there English grammer.

Tom:

Quite familiar with the Timex Speed+Distance unit you mention (I have been using one for about 6 months). I find it to be a rather interesting training tool (use it for running intervals on the road, rather than going to a track).

However, a couple of months ago this press release came forth:

Timex Trainer, companion software for the new Timex BodyLink® System introduced Thursday, January 9th at the Consumer Electronics Show in Las Vegas. The software comes bundled with their newest product, the Data Recorder which captures Speed, Distance and Heart Rate information.



Does your Timex rep. Scott Parr have any info. to share on this? Speed+Distance+Heartrate all in one! Sure would beat having to wear a separate heartrate monitor unit (i.e. another Timex heartrate watch, or Polar heartrate monitor) along with the Timex Speed+Distance unit! The press release indicated product release in the Spring of '03.

Also, does Scott know if hilly terrain is measured as if it were flat? Or does the unit account for elevation changes (maybe through triangulation of the GPS satellites)?

Thanks for your time and help!!!!

Jeff

I have received some specific information regarding this product but have been asked to withhold release of this information pending approval from Timex.

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Tom Demerly
The Tri Shop.com

Maybe we can compare notes... I did my own evaluation about 7-8 months ago... I compared my accuracy to the following:

1) Rolotape measured courses (1 mile increments, 1K increments up to 5k for runs and up to 20k bike course)

2) State Highway dept. surveyed distances (1 mile increments)

Elevation changes were noted against survey maps. Although, the elevation differences were extremely low - yep, it was tested on very flat terrain.

Without going into details and taken from memory... the difference in distance calculated by the Timex S+D and actual distance was extremely accurate... less than 1% diff. 80-90% of the time.

FWIW Joe Moya

I'm sure you've thought of this but one thing to test is the ability of the unit to stay connected through foliage. My experience has been that most older handheld GPS units do badly when trying to acquire a signal through foliage. I'd be interested to see if the sensitivity of the antennae has improved since I live in the northwest and do a lot of running and xc skiing in forests. Sounds like a fun test protocol you worked out.

Joe,

Thanks for sharing the results of your test. It sounds like the SDS is pretty accurate. Hills shouldn't make much of a difference even if the distance is measured as if on a flat plane. The difference in a flat road vs the distance up a 10% grade is only about 1/2%. I think more inaccuracy could result from losing the signal while running under trees or between buildings. Did you have any problems with that?

Thanks,

Paul

Unfortunately, the Great Plains of N. America doesn't provide a lot of trees to test this device. However, I have worn it four times in areas that had lots of tree's... During those 10k runs - distance set by Rolotape, I saw very little difference in distance accuracy. However, If your batteries are weak AND you have lots of tree's then I did find a bit more inaccuracy in distances. That small amount was about 2-4ft per 10k... bear in mind, that only occured twice... so, I can't say for sure that is a consistent problem. By the same token, 2-4 ft. on a 10k course is not too shabby... heck, I could have indavertantly cut a few corners and had that kind of an error.

The moral to the story seem to be this... errors in distance calculation seem to revolve around these reasons (in order of highest impact)

1) Satellite syncing capacity... Seems like most complaints about inaccuracy comes from Australia and New Zealand... could be a satellite thing. Mountains also can effect the Satellite syncing... as well as trees... but, I have had more problems with underpasses. And, I have not much (if any) problem with buildings. Maybe some in a multi-high rise city (such as NY) can be a better guide to the Timex S+D accuracy.

2) Battery strength... this is probably the biggest reasons I found inaccuracy in my Timex S+D.

3) Mountain running.... (not just hill's). Numerous extreme elevation changes can effect the distance.... Specially Loop courses and/or canyons. I tried it once in a steep canyon... didn't work very well.

Well, that's what I have noted during my use and abuse of my Timex S+D. All in All, the thing is accurate... I believe it was a rower that just loved the thing... it was an excellent pacing tool. And in open water, it showed his exact distance... plus, he didn't have to worry about drift not being calculated into his training distance. I guess in running and biking you can have course drift also.... however, we call it cutting corners.

FWIW Joe Moya