Recommended HR Chest Strap

If you only intend to use the 935, garmin will be fine. However, I would suggest considering a dual-band model, since that will give you more flexibility and future-proof compatibility (can be used with the the garmin but also with phones, apple tv, or bluetooth-only watches - simultaneously if you want). The Wahoo tickr is one of the most recommended ones out there.

Somethings to ask yourself first:

What type of exercise do you usually do? Do you run/bike/swim? Are you more of a healthy person doing exercise routines over those prementioned things? Are you weight lifting? Crossfit? etc..

Like everything else, buying products within the sphere of the root company will be better supported than outside of it. Garmin chest straps working on Garmin watch (in the case of the 935) two levels of running dynamic information (HRM-Run/Tri). Garmin Straps are ANT + only and work well with the firstbeat metrics (Anaerobic/Aerobic etc..) whereas not so well with, let's say, Polar's H10. As for HR accuracy, I find using the Garmin strap very close to actual on my Garmin watch vs. using my H10 which looks to lag in the polling.

If you are a runner and that's it (and maybe work out in other fashions) The HRM-Run is fine. If you do more like bike and swim, the HRM-Tri (with the optional HRM-Swim package strap) is your better bet. If you want a 3rd party strap, Polar's H10 or Wahoo TickrX is the better choice, though, in the case of the TickrX, it's dual-band (ANT+BTS) but is old now.

I do having a feeling we are getting new gen Garmin straps very soon though.

It depends on what you do in terms of sport, and what data you want.

Garmin's base model will work fine in terms of HR data for a variety of sports. Note that sweat can accumulate over time in the fabric of the strap, and lead to false readings. The fabric strap needs to be replaced every 12-18 months, but these can be picked up pretty cheap (keep the sensor unit and attach it to the new strap). Regular washing can extend the life of the strap.

The HRM-RUN adds running dynamics - basically measuring Ground Contact Time, Vertical Oscillation, L/R balance, and even Running Power. All of this sounds geekishly cool, but I'm not sure that sports science or coaching techniques have yet caught up with my to make actionable use of all this yet - this may change in the future. The strap of the HRM-RUN is not replaceable, although the design is supposedly less susceptible to sweat accumulation - I don't think it has been out on the market long enough to prove this conclusively, but I haven't heard of too many problems on this aspect.

HRM-TRI has Running Dynamics, but also has the ability to store HR data while swimming, and forward it to the watch later when you are out of the water. This is also useful for contact sports where you have to leave your watch on the sidelines.

Baldo's suggestion of dual band (ANT+ and Bluetooth) does offer more future proofing, but all of Garmin's straps are ANT+ only - the 935 watch will receive both ANT+ and Bluetooth. Wahoo's Tickr is probably the best option here. Polar does have some compatibility issues, but it is workable.

Agree with all of the above. However, if you are only running see if you can get a soft strap HR-Run with the detachable module, that's the best way to go. The straps tend to go before the sensor module leaving you with an expensive replacement if it's all-in-one. The strap at the bottom of the the first image - https://the5krunner.com/2015/04/03/l...strap-history/

FWIW, I do multisport - swimrun and triathlon. As I'm not fussed about HR when swimming, the HRM-Run (4) is fine for me.

Thanks for all the replies.
I run and bike and that's it. Im currently training for the London Marathon and i will regularly bike to work and back (30 miles round trip)
I don't really do swimming and don't think i will unless i do maybe have an urge maybe to do a triathlon. I don't do weights and hate the gym. Its running and cycling really. So a strap that would be best for that is what I'm after.

Ive bought several trackers before but asked for loads of reviews and did loads of research and finally settled on the 935 and it is amazing. Its just from what I've read, that the wrist heart rate monitoring can be slightly out (on all wrist based HR) compared to a chest strap. Im specifically trying to train my heart in certain zones and getting real time accurate HR readings is vital to whether i need to slow down or speed up. Im just looking for the best way and the best device (like finally buying a 935)

Regarding Ant + or Bluetooth ? I will be sticking with the 935 for a long time so i don't know if i need to have both bluetooth and ANT +

Comfort is vital. Especially doing a marathon. I don't mind spending £100 or £30 as long as i buy what is possibly the best monitor and most accurate.(along with comfort lol)

Again, thanks for your responses.....

Regarding Ant + or Bluetooth ? I will be sticking with the 935 for a long time so i don't know if i need to have both bluetooth and ANT +

You don't NEED either, but the watch will connect to either. If you're biking, you probably are using at most, Speed/Cadence/Bike comp/power meter/Chest strap. You can use multiple ANT + devices at once and all of those will connect to the watch. If you had one out of the mix that is BTS it will also connect to the watch alongside the ANT+ devices just via BT.

Comfort is vital. Especially doing a marathon. I don't mind spending £100 or £30 as long as i buy what is possibly the best monitor and most accurate.(along with comfort lol)

I've used the HRM-Tri for years, it has never felt uncomfortable to me (Running up to half-marathon, Biking, HIIT, Weight lifting). No chafing, no burning, nothing. HRM-Run is the same physical band. The polar H10 is really soft, but I find it moves more. The Tickr X is painful for me. I never liked their band.

Comfort is vital.

In which case a Garmin HRM-Run with or without the detachable centre module will be fine. I've worn mine for ultramarathons up to 15 hrs without any problems

Thanks. I couldn't find a HRM run with the detachable module so i went for the Garmin premium heart rate monitor https://www.wiggle.co.uk/garmin-premium-heart-rate-monitor-strap-1/?sku=5360574952
Thanks for all your help

Thanks for the help, ive decided to go with this. https://www.wiggle.co.uk/garmin-premium-heart-rate-monitor-strap-1/?sku=5360574952

I couldn't find a HRM run with the detachable module so i went for the Garmin premium heart rate monitor

The module on this strap is detachable.