I have the FR 935 and the 510. The only real reason I even wear the 935, while riding, is to broadcast my HR to the 510 (no strap required).

Advantage on race day is......I don't have to switch anything from my wrist to my bike.

I may or may not end up with 2 files. I actually don't know how Garmin Connect handles it when it likely gets two files for the same workout. I record my workouts, manually, in another file.

I have mounts on my road, TT and fat bikes (for the 510).

I have a 935 and 520. I wear my 935 for swimming, running, and races. I never wear my 935 during bike training. If I did wear my 935 during a training ride, I wouldn't even record the ride. That's wha my 520 is for.

The advantage of having a dedicated bike computer is that you can easily see the screen and have it right in front of you to see data (power, hr, time, etc). And during a race, you don't have to worry about grabbing your watch from the QR.

I do track the bike portion on my 935 for races. Mainly because I want to know what my overall time is going to be like for the race a few miles before the finish. May sound silly but if I'm close to breaking some time barrier, I want to know it. I always end up deleting the bike portion on the 935 after the race.

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I have a 935 with the tri strap and a 520. I started with a 520 and then added the 935 later.

935 for recording everything on swim and run. For bike I have the sensors hooked up to it as well. I only use my 520 for display purposes while riding (HR strap, speed and cadence all connected as well).

When a ride starts or ends I do it on both, but only save and upload via the 935.

Seems to work pretty well with accurate info.

Ditto the other comments. The 520 is highly optimized for biking with its big screen and massive battery. They are so cheap now that it is almost in no-brainer space. If you use both at the same time, you get 2 Garmin connect entries. But it takes about 5 seconds to delete the one you don’t want.

Currently having the same debate (own a 935 and thinking about picking up a 520). Good thread with good info - just wanted to say thanks. Seems like a bike computer is still helpful to have (but not necessary) provided you have the funds for it.

which mount do you use for the 520 on the aerobars? the Garmin one?

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3toronto Triathlon

I use a alden design custom garmin mount because my extensions aren't circular (zipp evo). I would recommend looking at the barfly TT or k-edge mounts for aero bars.

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Ha! Which one??? I have the same extensions too lol

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3toronto Triathlon

Have the 920xt and 820. I rarely, if ever wear my watch during training on the bike. For something like an FTP test, I do use both in case one starts acting up, I don't want to ruin a test. Just delete one.

Last race, my auto sleep function was activated on the 820 and I didn't feel like stopping to set it up right. Just flipped the 920xt to the underside of my wrist and could read the data thay way.

Still nicer to have the 820 showing more data fields

what mount would someone use for a 520 while using a BTA? I'm going to be in the market for a new BTA setup, and that was the only stalling my 520 purchase.

I have a profile design HC system. before I just used the cage with a standard bottle flipped backwards which put the computer in my face. But with the straw/bottle system I had to flip it back like it was designed. puts the computer way too far back. Looking for a good solution myself.

http://alden-designs.com/...-computer-mount.html

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I use a Garmin 520 and 920xt and like it a lot. When I race I do use both although I start the bike computer when I can and will often stop it before I get to the dismount area... it is easier to read as a tool while I'm biking vs. my wrist for sure. That's about the only time I have double files and its only for the bike section, so not really a problem.

I prefer it vs. just using a watch for everything... a bike computer if you can afford to have both is worth it IMO. For bike training I use the 520 100% of the time.

I have both (though with different branding/devices):

I used my suunto ambit2 as my bike computer for two years before adding a wahoo bolt. The ambit was ok as a bike computer -- good data, no dropouts -- but I went for the dedicated unit for 2 reasons: more display real estate (7-9 fields instead of 3 with much better visibility) and navigation (I really like this feature; no more stopping to check directions on my phone). For those reasons alone, the bolt has been well worth it. Training peaks integration (new this summer) was a bonus, albeit a very nice one.

Like others, I only use my ambit on the bike for races (no reason to stop and restart; just record the full race), or if I forget the bolt in a charger or something. I wear the ambit all the time, but for most bike rides, it's just a watch.

Someone asked about BTA mounting for the bike computer; I use the standard quarter turn mount (the one with rubber bands) on my aerobar right next to the BTA bottle. It tucks in nicely between my arm and the bottle, out of the air but very visible. Just twist it slightly out to do the quarter turn. Mounting on top of a water bottle seems cool, but I didn't want to buy another piece of hardware...

Most people all use both in similar ways. I'll expand just a bit how a race goes for me:

• watch on the entire race, setup as multisport, recording each leg and transitions
• bike computer on the bike, ready to start (no auto turn-off or auto-sleep)

• The watch is the primary recorder of everything and I try to hit the lap button as close as possible to the mats
• The bike computer is secondary and more just to see the data easier


• I'll hit start after I get to speed (so my average power doesn't include the startup surge)
• I usually don't hit stop till after the race
• Since all of my gadgets are connected to both, I usually ditch the computer data. The only extra it has is temperature info, but, eh...I can manually enter that as a note or metric.

After the race, I chop up the legs in Golden Cheetah and save them all as separate workouts. If you use Garmin connect, then it saves the single multisport file with separate legs...fancy.

I’m in the same boat as some others on here.

I have a Fenix 5, which to date, I use for swim/bike/run— obviously, on bike/run, I get HR.

Just got my first power meter (Pioneer Single arm) and now need a computer to read power. Assuming I follow the lead of others on here, and start using my Fenix for JUST swim/run, then I need a HR monitor to get HR on the bike I guess? It’s been nice having the Fenix and not needing to wear a monitor on my chest. That said, seems like switching to the computer (I guess a 520?) is the way to go on the bike since I now have a power meter?

Any advice is appreciated.

Another consideration. I have 935, and and old 910. I also have to use ANT dongle to my Mac to run TrainerRoad because the BT protocol is too old. My older PowerTap SL+ can only opconnect to a single head unit at a time, I think. Seems that my Tacx smart can do multiple. It gives me pause to get a 520 since I would wear the 935 during Tris, but just the 520 when just riding.

The Fenix will read power as well. So no need to get a bike computer unless you want a bigger screen and/or a readout on the bars as well as wrist. Personally I also find the wrist based HR to be pretty unreliable when cycling and wouldn't really count on it for any serious run training or racing either. YMMV.

I use this..
https://speedfil.com/z4z4plus

No complaints here.

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Team Zoot - Great Lakes