Garmin Speed / Cadence Sensor Really Needed?

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

Wondering how many of you have ditched the Garmin (or other brand) speed / cadence sensor? Cadence is not a useful metric for me, so given the head unit is capable of calculating speed just fine on its own, it seems redundent. And would save 50+ grams.

by Weenie

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by torob

I ditched my speed sensor two yrs ago and don’t miss it at all. Bin it.
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by Monkeyfudger

Not had one in years (apart from on track bike) originally ‘cos they look ugly... I believe cadence is a useful measurement though so I went and bought a Wahoo cadence sensor for the MTB, PM’s give me cadence on the road bikes.
Last edited by Monkeyfudger on Sun Nov 11, 2018 4:51 pm, edited 1 time in total.

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by mattr

Cadence i like to have for various drills. Speed is pretty much irrelevant now with the accuracy and signal stability of GPS.

Only time i have an issue is when i go direct from home MTBing in poor weather. a) i'm in a valley b) where i ride is pretty heavily forested. Can take a while to get a lock if i switch on as i start the ride. So not only do i have no trail, i have no speed either.
This used to be an issue on the road until they cleared some of the bigger trees (it used to be a tree tunnel for 2 or 3 hundred metres on our road, now it's open skies)

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by Butcher

Cadence comes from my power meter, speed from GPS. I have never seen a cadence sensor that looked good. I would dump it.

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by jih

I don't bother. Speed from GPS. Most powermeters do cadence.

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by Miller

Still have a speed sensor for when I do a roller session but don't use them anymore for anything else.

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by themidge

I've never even bothered to get either in the first place. The GPS speed on a Garmin is perfectly fine for everything short of scientific testing, quite why anyone feels the need for it I'm not sure, especially when Strava uses the GPS speed anyway (I think, don't quote me on that). 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.

Of course, the main reason not to have the sensors is that they're ugly and add weight! :D

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by ParisCarbon

Cadence coming from PM, I just use the GPS for speed... off topic, but I find my SRM PC8 VERY slow to acquire satellites.. I stand in the front yard sometimes for several minutes with no line of site interference and get nothing, give up and then ride 600 meters before it picks up... the Garmin gets the satellites in the house! Probably why you still see guys with the speed pods on the SRM...

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by Alexandrumarian

I use the Garmin speed on my main bike. I find thec gps speed on the other bikes a bit laggy / jumpy, can be pretty annoying in comparison.

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by Calnago

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. Just look at your route around turns after you’ve uploaded your fit files if you want to see the jigsaw puzzle of a route that “Smart Recording” has the potential to produce. I always recommend setting the recording interval on a Garmin head unit to 1 second, and it’s still surprising how many people just don’t even know what you’re talking about when you ask if they’ve got it set for smart recording or 1 second interval recording. So for me, I really do like the sensor... but it’s not a big deal really at the end of the day. The ride is ultimately the same whether you have a speed sensor, no sensor, or even no computer at all.
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if you dont need cadance just lett it off, if you have gps speed and dont live in the woods get it off too
- ridley fenix sl 105 - not lightweight
- sworks tarmac sl 5 r8050 di2 - vision tc 24 wheels = 7,1kg

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by Finx

There is a lot of tree cover where I live, and I find GPS speed can be quite sketchy, so I do use a speed sensor on my front wheel.

I have Stages PMs on most of my bikes, so cadence is there, although I rarely pay any attention to it.

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by WR74

My Garmin use to freeze up when using the speed sensor. Ditched it years ago, speed from the GPS works perfectly. Still have the cadence sensor fitted but that should go soon seeing as I fitted a quark PM recently.

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by cro2

I ditched the speed sensor when the plastic cracked and some moisture got inside and destroyed the electronics. I never really felt the need to go back as it works very reliably. The only problem is that on rare occasions when I do hill intervals on a road with pretty heave tree coverage on the sides Garmin autopauses my ride. On the other hand, I see cadance as a valuable metric and would never drop it. Luckily p2m powermeter suppliees cadence alongside power so I don't have to use a dedicated sensor.

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