LondonSkaters Speed Team - Speed Skating & Rollerblading Club in London

Natasha · Joined: 09 Jul 2004 Posts: 2973 Location: Basingstoke

I want to be able to measure distance and speed. Here's an example of what I found in Google: http://www.cccyclery.com/inline.html

Hans · Posted: Sat Jan 01, 2005 8:07 pm Subject:

that looks interesting...

Mikey-two-Names · Joined: 24 Feb 2004 Posts: 4108

Why don't you buy one and then tell us what it's like? Then at least the rest of us can choose the best system. Wink

Alastair · Posted: Sun Jan 02, 2005 12:38 am Subject:

I always have doubts about these things accuracy compared to a GPS-based system. They are usually mounted on one boot. Although, the relative difference may be negligible, it has to make calculations (and probably some assumptions) between the calibrated boot and the non-calibrated boot. For bicycles it is different as the wheels are travelling in more or less the same direction and at the same speed regardless of which wheel is being calibrated.

Natasha · Joined: 09 Jul 2004 Posts: 2973 Location: Basingstoke

I guess it would make sense for me to buy one so we can at least test it against a bike one...

lemming · Joined: 05 Jan 2005 Posts: 693 Location: Reading, UK

quick hello first - Hello.

Just joined / joining and hoping for dry on Saturday at Mike's video outing.

As far as these things go, I've just got a Garmin ForeTrex 201. GPS. Haven't tried it on my skates yet, but it seemed pretty accurate when out walking and worked well in the car. I intend to bring it on Saturday if anyone's interested. Downside is it will now cost you about 180 english pounds. Might find it cheaper if you hunt though..

Natasha · Joined: 09 Jul 2004 Posts: 2973 Location: Basingstoke

Hi, and welcome! If you could bring it on Sat, that would be great!

lemming · Joined: 05 Jan 2005 Posts: 693 Location: Reading, UK

No probs - I'll be there as long as it's on and I'm not stuck at the other place I need to go.

Mikey-two-Names · Joined: 24 Feb 2004 Posts: 4108

You've not seen Ray's? His is almost the same, only it's the forerunner rather than the foretrex. I've no idea what the difference is.

dan_b · Joined: 15 Jun 2004 Posts: 2428

Natasha · Joined: 09 Jul 2004 Posts: 2973 Location: Basingstoke

Whoa! They seem expensive, I can get a heart rate monitor for that! I guess I was attracted by the ccyclery.com one because it was as cheap as chips. Now that I think of it, my phone has GPS, not as handy as a watch, but it'll do till the crappy one arrives. Thanks for the advice chaps.

dan_b · Joined: 15 Jun 2004 Posts: 2428

dan_b · Joined: 15 Jun 2004 Posts: 2428

A year later and I've basically not used the thing at all since the novelty wore off - it's just too bulky. Good for races insofar as it saves me having to look out for distance markers, though.

The Forerunner 305 does seem like a nicer piece of kit, though.

Mr. T · Joined: 30 May 2005 Posts: 65 Location: London

My 2p.

I am very skeptical about the tool in the opening post of the thread (at least it is cheap, but if it ended up on e-bay, I doubt it was any good).

Over the years I have seen many tools appearing, but they always did not prove to do what they claim. So far, only GPS systems have proved useful. However, since I lived in Minneapolis where in the Winter we skate indoor at the Metrodome, GPS systems indoor are not so good.... for obvious reasons. I have seen and used others.

http://www.rollerblading.com.au/microsportspeedometer.htm
http://www.meds.at/de/products/skaty.htm

When I compared the Garmin Forerunner 101 with the Microsport (and did that in a certified marathon in Saint Paul in 2004) the Garmin Forerunner measured the distance at 42km, the Microsport at 40.6km.

I had a conversation with the engineers at Microsport and they told me that their instruments are supposed to have a 5% error margin (what I found). The Garmin GPS system is annoying when you are in wooded areas (trail skate which I did often in the US). I noticed, for example, that in my loop at Hyde Park (start at parking lot of Serpentine Road, go east, take the bike path to Speaker's Corner than North Carriage Road,
West Carriage Road and back to the Serpentine Road) when I entered the bike path to take me from the east end of Serpentine Road to North Carriage Road, I tended to loose the signal in particular if I put my hands behind my back. That does not happen with the Microsport wheel. However the Microsport wheel wears out and you need to recalibrate the system from time to time, at leat.

As far as the readings for speed are concerned: Microsport wheel and Garmin never agreed but the difference was within 5%. I checked the Garmin Forerunner in my car and found it to provide measurements in agreement with my speedometre.

During my conversation with the engineers at Microsport I learned that computers for skating are really complicated. Since the wheels are not always in contact with the ground, a lot of mathematical modelling is required to estimate the speed.

One advantage of Microsport is that it has a built in algorithm to measure the calory consumption (based on weight and speed of the skater).

Rick · Joined: 25 Feb 2004 Posts: 5914

A lot of stuff ends up on ebay because people don't use it, not because it is rubbish so I wouldn't judge anything on that basis.

Some GPS systems tend to be rather poor in many parts of London because of tallist buildings and narrow streets that they can have difficulty staying in contact with the satellites. My Garmin eTrex is particularly poor. It's not designed for runners who go through that sort of terrain. It's for hiking in open spaces and it is also an early model so it's probably quite rough. I don't use it much.