Garmin Speed / Cadence Sensor Really Needed?

Discuss light weight issues concerning road bikes & parts.
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by jlok

I don't look at speed at all after I got a power meter. If I really need it, GPS speed it is then. One less sensor to mount on my bike.
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by angrylegs

GPS speed works alright (magnet is more accurate though) and you don't really need the cadence sensor if you have a decent sense of your pedaling habits/needs. If you've got a power meter though you've got the cadence sensor anyway. Don't really need the outboard sensors - those I ditched when I got a power meter.

by Weenie

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by LiquidCooled

I still have a speed/cadence sensor on my bike. The speed sensor is definitely more accurate than GPS (especially when going uphill or downhill). Fortunately my Wahoo Bolt prioritizes speed from the sensor over speed from GPS. Unfortunately, the Bolt also prioritizes cadence from my power meter (which is spikey) over the cadence from the magnet and cadence sensor (which is very accurate).

My bike (TCR) came with the speed/cadence sensor nicely incorporated into the inner part of the chainstay. It's not an add-on, so it's very neat and tidy. If had another bike without that nice integration, I probably wouldn't add a separate speed/cadence sensor. I'd just rely on GPS and my power meter, despite their inaccuracies.

I do like to have cadence even though it's not a necessity. Same with speed. For me heart rate and power are much more important.
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by mattr

themidge wrote:
Sun Nov 11, 2018 5:43 pm
Cadence is another largely useless metric, if you're doing drills it's either going to be "pedal really slowly", "pedal normally", or "pedal as fast as you can", there's no need to be specific. Even if you wanted to do an incremental ramp test style cadence drill, just use your gears and a bit of road with a consistent gradient, which you'd want to use anyway. I suppose it might be useful to have the number in front of you if you were training yourself to ride at a specific cadence, but that's going to be the minority of people.
few things. Depends on the drills you are doing. Some of the ones i have done require a range of ~10 rpm, some 30-40 rpm away from where I am comfortable. It's fairly easy for the first few minutes, then gets progressively harder to keep the rpm down. Compounded by there being no such thing as a consistent gradient of any significant length in most of Europe.

It's also quite useful to keep an eye on towards the end of long single day events or after multiple days. As you tend to pedal slower unless there's something to give you a hint. (There is actually research on this.) Counting works. But usually concentrating on other things by that point in the proceedings.

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by robertbb

Calnago wrote:
Sun Nov 11, 2018 9:58 pm
Yeah... I still like the speed sensor. I know it’s dead accurate so long as your wheel circumference is right. It picks up immediately. It never loses the signal in forested areas which we have a lot of. And if you’re say... traversing a steep climb with switchbacks, GPS speed can be off (consider the potential confusion that the calculation for distance gps is figuring out if you’re climbing, versus horizontal, and also if there’s switchbacks involved), particularly if you have your Garmin set on “Smart” recording, which is really dumb recording.
+1. I use the Garmin one that mounts on the hub... it's pretty discrete.

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by nickf

Only use the him money sensor on the mountain bike. Way more accurate where there is a lot of tree cover

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by moyboy

Also remember newer Garmins have GPS + GLONASS for more accuracy at the expense of battery life.

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