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DAVEANDCHARMA
08-31-2009, 09:24 PM
Hi there,

received my 310xt last week and have used it extensively for running/swimming/kayaking and love it.
However, I have noticed the 'speed' function appears to be slow in comparison with my older forerunner 201 whilst sprinting. I have put both units side by side whilst the 201's speed is instant, the 310xt lags and takes 5-6 seconds to reach the 201's speed (but is accurate) It is quite annoying.
Both units have full satellite reception and when the data is imported, both tracks are identical and accurate.
Any ideas? Anybody have the same problem? Is there a setting to fix this?

Thanks Dave

-DAMON-
09-01-2009, 10:41 AM
DAVEANDCHARMA,

Have you downloaded the new firmware, version 2.60? If so, is the unit still slower than the Forerunner 201? If not, you can download the update at https://buy.garmin.com/shop/store/fr310update.jsp .

If the problem continues, you may need to reset the Forerunner. Be advised, this may erase all of your user data. To do so, with the Forerunner powered off, please press and hold MODE + POWER until the Forerunner powers on. You can then release the buttons and select YES.

-Damon-

DAVEANDCHARMA
09-02-2009, 12:00 AM
Thanks for your help Damon, Ive taken your advice and upgraded firmware to 2.60. Took both Forerunner units out for the test again (310xt & 201). No noticeable difference. The 201 has instant speed whilst the 310 takes 10-20 seconds to reach that speed and when I stop altogether, the 201 instantly stops but the 310xt slowly takes 10-20 seconds to stop. I use this feature extensively when sprint training. I think in Aviation terms they call it GPS lag?
Just tried to reset the unit and it is still continuing with the problem... (not really a problem, just annoying)... any other ideas?
Dave

IRONKEV
09-02-2009, 02:26 AM
Not sure if they are related issues (I have no intentions of hijacking the thread)

When I went out for a ride yesterday my speed shown by the unit (without speed and cadence sensor) was slightly slower than the fully calibrated cateye speed sensor on my bike.

At 25 30 mph it was typically between 1 and 2 miles slower

BBECKER39
09-02-2009, 12:24 PM
The speed takes some time to react because it is filtered in running mode. It don't think the same filter is applied in biking mode, so I think you will see the speed react faster if you switch to biking.

Edit: I may have been misinformed about bike mode not filtering speed. I will try to find out for sure.

DAVEANDCHARMA
09-02-2009, 10:00 PM
Hey BBECKER39, I never thought of that.

Yes, I have had it in 'run' mode and never tried bike or other modes... off to training to try it out (with fingers crossed)

thanks for your help

DW152
09-03-2009, 04:07 PM
Not sure if they are related issues (I have no intentions of hijacking the thread)

When I went out for a ride yesterday my speed shown by the unit (without speed and cadence sensor) was slightly slower than the fully calibrated cateye speed sensor on my bike.

At 25 30 mph it was typically between 1 and 2 miles slower

I still have the traditional spoke-and-magnet computer on four of my bikes, so I often compare the speed on my Garmin to that on my Cateye computer. The instantaneous speed often doesn't match, but the overall average will usually be close. This has never bothered me because the way they calculate speed is different and therefore I expect some uncorrelated values. I do notice that speed on the Garmin seems to be noticeably slower (a couple of MPH) when under tree cover, which I've just figured is an artifact of the way speed is calculated from GPS when the signal isn't very good.

PHILIPSHAMBROOK
09-03-2009, 08:10 PM
Not sure if they are related issues (I have no intentions of hijacking the thread)

When I went out for a ride yesterday my speed shown by the unit (without speed and cadence sensor) was slightly slower than the fully calibrated cateye speed sensor on my bike.

At 25 30 mph it was typically between 1 and 2 miles slower

A true pedant would ask you how often you calibrated your Cateye and what are the tolerances in measurement. I suspect the difference you see may well be within the margin of error. Tyre pressure, barometric pressure, temperature will all affect the air in your tyre and hence the diameter of the wheel. This of course will affect the accuracy of your Cateye. Whether you are in the open or under trees or over cover will affect the GPS signal.

It's easy to forget that although these devices are quite sophisticated and reasonably accurate, they are not always what you would call a precision instrument. I include in this any training tool whether it be GPS, HRM or otherwise. I think sometimes we expect a level of accuracy that is not there. For training they are great tools. But I would never bet my life on their precision.

WROSEND
09-05-2009, 11:14 PM
I have had the 310XT for about a week now and have noticed the same lag in speed. I also have a Garmin handheld GPS 60CSx to compare to where the speed seems like it updates much quicker without delay. I have not tried any upgrades yet for the 310. Otherwise, I like the unit.