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TerryDav 07-01-07 08:59 PM

Garmin 305 Newbie: I need help
Okay, I searched Garmin and didn't find an answer to my issues, so here it goes with a new post.

I just received a Garmin 305 w/HRM & Cadence for fathers day. I finally got it all charged up and installed and took off on it's maiden voyage this morning. I live in WA state and I'm in my final stages of training for RAMROD, so I took the unit on a very long ride up to Paradise and found the following problems:
1) Battery life was only 7 hours and 44 minutes, do I have to purchase a portable charge for the road to cover very long rides 9-12 hours?
2) The unit had problems maintain a satellite feed while up near and in the Mt. Rainer Park (most likely trees), no big deal but the unit keep adding 10 miles onto my distance each time it synced up. The ride was only 124 miles, but my data says I did 176. What am I doing wrong, should I be turning off the GPS in areas that may have sync problems.
3) The unit also struggles with my speed figures, in one down hill stretch it had me going 63 mph. Now I consider myself a strong rider but even I must call foul on data like it was pulling in. Is there any way that I can have the speed and distance taken from the cadence unit instead of the GPS?

At this point, I'm highly disappointed in my new present. Any help you can offer would be great.:(


markhr 07-01-07 09:31 PM

try here

TerryDav 07-01-07 11:51 PM

Well, spent the last hour looking over your links. I'll order the battery back-up system, so item #1 is resolved. Item #2 & #3 are disappointments that Garmin hasn't looked for an easy solution to solve the speed and distance problem. Well, I think I'm going to add back my cateye computer to have something to compare against.

Thanks again for the reply.

Torgrot 07-02-07 07:27 AM

Have you updated the software on the Garmin? There are two files one is for the chipset and the other is for the unit itself. The latest software updates really fixed a lot of problems for me.


aham23 07-02-07 10:03 AM

update the unit, firmware, software, and chipset. before using it on a ride you need to power it up out in the open sky, live it sit until it locks on all 30 sats. then mount it to the bike. this process takes me about two minutes and i have no fluctuating speed issues. later.

edmcnierney 07-03-07 08:31 PM


Originally Posted by aham23
...until it locks on all 30 sats...

This will never happen, as most of those 30 sats are, at any given moment, on the other side of the Earth from you. If you have a good signal from 6 or 7 you're fine, although letting the unit sit for a few minutes will improve the quality of the data collected during the first few minutes of your ride. Recreational GPS units use time-based filtering to improve the quality of their results; they will improve whether you're moving or standing still, but if you wait a few minutes you'll discard the initial, poorest-quality data.

I do no such fiddling around, and don't have any complaints about my 305 performance. The software updates are definitely a good idea. Actually, I DO have one complaint - the ridiculously high "calories burned" calculation!

patrick07 07-03-07 08:37 PM

I just turn on my unit and set it near an open window for a few minutes before I'm ready to leave.

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