As far as optical HR monitoring, there are several options available. I have been using the Schosce Rhythm + plus for almost a year on bike/run and love it. Has about a 6hr battery life and syncs over both Bluetooth and AnT. Pair that with any cheap run watch and there you go. Only issues I have had is sometimes it will get a cadence lock at the beginning of a run if it’s cool out and your arms are cold...(less blood flow at skin surface), but it seems to clear up within 5 min or so...and that only occasionally happens. Otherwise I find it very accurate.

Get a Scootch arm band and use any running watch with Ant+ or BTLE. Separating the two has the added advantage that it will work when it gets cold outside and you have to wear the watch over top of you long sleeve shirt or jacket.

John

I had the vivosmart hr that would pair with my 920xt for saving all the data in one place. It was ok, but definitely drifted way off more often that I would have liked. The strap broke and I haven't bothered fixing it if that tells you anything.

I know a few people that are happy with the Scosche Rhythm, I'm thinking about getting one.

The thing with optical wrist HR is that it is highly individually dependent. For some people, many products work great. And for others, they all suck. I have a 735XT and it is OK. I reverted back to using an optical Scosche Rhythm+ with my watch. That is fantastic. My problem is that the watch would frequently do two things. One is cadence lock: it would often lock into my run cadence as the watch moved on my wrist, and once it did this, it would hold on and not revert back to actual HR. The other is that when I did some hard hill climbs with elevated HR, for some odd reason, it would not show the high HR. But, it would normally show high HR in most other running circumstances.

If you wear a 735XT tight enough, it reduces the cadence lock problem. But, I just liked the data quality of the Rhythm+ overall, and that is what I am using. I use the watch's built-in HR as backup, when I don't want to bring along the Rhythm+ or its battery dies.

Optical HR works really well for me. I currently have a 935 and previously had a 235. I only switched to the 935 for the battery life (ultrarunning).

p.s. I've got the 235 for sale in the classified section at the moment ($200).

Where are you getting a Garmin 735 for 250+?

That's the Garmin 235 price

Seems like it's around $300 when I'm doing a quick search, so I assume it'd be hard to get it for less than $250, so said "$250+"...

Thanks all for the Schosce advice, looks like a relatively low cost solution, so long as my 920xt keeps working.

Go with Scosche Rhythm+. The key is you DO have to cinch it TIGHT. It will feel uncomfortable at first, but it doesn't hurt or damage your skin.

I've also found it gets bouts of haywire readings when your skin gets too cold in that area, probably due to restricted blood flow in that area until you get sweaty/hot enough to circulate enough blood for the optical sensor to pick it up again. But all in all, it's very good, very reliable, and most importantly, does NOT suffer the long-term eventual degradation that the chest-strap electrical HRMs all suffer from after 4-6 months of regular use.

I, however, still favor racing tris with a HR strap monitor - I still haven't found a great way to deal with the Scosche on the swim/wetsuit, and putting it on in T1 can be annoying if you've optimized your transition times.

I've been using a Scosche Rhythm+ for almost 2 years. It was bit annoying at first as it turned out to be a bit location critical on me and I often had loss of signal. However once I figured out the best place to put it, it became pretty flawless....for running.
I now put it high on my arm, just below my shoulder with the unit facing forward and the strap fastened moderately tightly. I virtually never lose signal and it produces HR data that's as good as my Garmin chest strap.
However, I don't use it for cycling. I find the chest strap really irritating to run with but it's fine on the bike. I used to have some problems with the Scosche losing HR when on the bike. I never figured out why. Then again I didn't put much effort into figuring it out as I'm fine with the chest strap on the bike.

The one weakness of the Scosche is the battery. It won't last you an IM if you turn it on from the start unless you're REALLY quick. I've used it for several triathlons and I wear it from the start. I've had no problems with putting a wetsuit over it but that may be dependent on how you wear it - upper arm seems fine!

I'm quite happy with my vivoactive hr, for running, cycling, and pretty much everything else. And you can't beat the price. If I'm doing an LT test or something, I'll wear a chest strap.

I have a 935, but I bought my wife a Vivo 3 a few weeks ago. It's a solid training tool for the money ($249).

I have a garmin 935 and love it. My son works in retail and was able to get it for almost half off the retail price so that makes me like it even more

2nd the 935. Accurate enough for me. I decided against the Scosche Rhythm+ because I didn't want to have a funky forearm tan.