Speed and cadence sensors

wildpig

After reading a few articles, I can't quite work it out. Now I'm getting into my cycling a bit more...

What's the point in them?
Which one is more useful, if I was only going to get one?

And to buy, or not to buy, and if not, where else should my cash go to make riding more... data heavy...?

mfin

What's the point?

One lets you measure speed (which updates quicker than speed calculated purely by GPS and keeps working under tree cover), and the other measures cadence.

A few years back, a lot of Garmins came with a GSC-10 which measures both. IMO still worth grabbing one if they come up in the classifieds. Use a neo magnet on the pedal spindle and it saves cable tying one to the crank arm which will likely mark it in time.

Some people don't see the point in cadence, if you're new to cycling though using one can get you into good habits if you have bad ones regarding cadence. There's a prat on here somewhere who will try to convince you to use an unusually low cadence, so if you get that advice ignore it.

awavey

but that doesnt answer whats the point though

in a non professional, not training situation, as most recreational riders are Id say out of both I probably find real time cadence more useful on a ride, than really caring too much about how accurate the speed really is, certainly on a decent GPS device there shouldnt be much difference on the speed calculation.

whilst cadence, though you ought to be feeling in your legs anyway if you are churning too big a gear, though it always surprises me to see people still suffering doing it, you get to see real time whats your comfortable pace, & you know roughly the marks you should be hitting and can keep ontop of the gears with it, thats the point of it IMO

as sometimes during a ride Ill be feeling Ive started not to move as comfortably, finding it harder to maintain the same speed as either hit an elevation thats not obvious, or a slight wind direction change, and Ill look down and see oh my cadence has dropped 10-15 revs that I hadnt really noticed, knock it down a gear and it gets back up to feeling more comfortable and generally your speed increases. no doubt old grizzled club riders just use their own senses and would say well your body was telling you to do the same thing, but seeing the numbers can be a good prompter I think.

post ride well its about as much use as knowing what the temperature was, its data, you can see how its been across a ride but its debateable how useful it is then.

wongataa

awavey wrote:

but that doesnt answer whats the point though

in a non professional, not training situation, as most recreational riders are Id say out of both I probably find real time cadence more useful on a ride, than really caring too much about how accurate the speed really is, certainly on a decent GPS device there shouldnt be much difference on the speed calculation.

Usually the GPS speed is fine. But it can jump around a bit when you are cycling at a steady speed. A speed sensor prevents this. If you cycle in areas of reduced sky visibility (under tree cover, areas with lots of tall buildings, tunnels, narrow valleys, etc) the GPS speed reading can be unreliable. A sensor solves this. When cycling slowly up steep hills the GPS speed reading can be unreliable. A speed sensor solves this. If the GPS speed reading is unreliable the recorded distance will be unreliable. A speed sensor solves this. It is not a big issue but some people prefer the speed/distance readings to be reliable and as accurate as they can get.

surfercyclist

I use cadence as the main metric to follow during a ride, for me maintaining a cadence of around 80-90 feels best and so I try and maintain that. The other one for me is HR, mainly on steep climbs to ensure I don't blow up. Yes, in both cases you can judge them but I find having a reading very helpful. I don't have a power meter but would use that as well if I did.
As for speed, pretty meaningless other than to you. I find average speed a handy indication of progress BUT so many other variables come into play(terrain, wind, heat, cold, fatigue etc).

Like most things in cycling you don't actually "need" them but they are useful.

StillGoing

awavey wrote:

but that doesnt answer whats the point though

in a non professional, not training situation, as most recreational riders are Id say out of both I probably find real time cadence more useful on a ride, than really caring too much about how accurate the speed really is, certainly on a decent GPS device there shouldnt be much difference on the speed calculation.

whilst cadence, though you ought to be feeling in your legs anyway if you are churning too big a gear, though it always surprises me to see people still suffering doing it, you get to see real time whats your comfortable pace, & you know roughly the marks you should be hitting and can keep ontop of the gears with it, thats the point of it IMO

as sometimes during a ride Ill be feeling Ive started not to move as comfortably, finding it harder to maintain the same speed as either hit an elevation thats not obvious, or a slight wind direction change, and Ill look down and see oh my cadence has dropped 10-15 revs that I hadnt really noticed, knock it down a gear and it gets back up to feeling more comfortable and generally your speed increases. no doubt old grizzled club riders just use their own senses and would say well your body was telling you to do the same thing, but seeing the numbers can be a good prompter I think.

post ride well its about as much use as knowing what the temperature was, its data, you can see how its been across a ride but its debateable how useful it is then.

GPS speed can vary whereas a speed sensor doesn't. There's nothing wrong with just relying on GPS if you're a casual cyclist not interested in stats.

Cadence on the other hand is important. It isn't about knowing whether you're grinding a big gear or not. Your RPM is important in order to be efficient. Too low a cadence and you'll tire the legs, too high and you'll tire yourself aerobically. A cadence of around 80-95rpm can feel overly fast for new riders who would likely be surprised to find that their cadence isn't even 60rpm.

wildpig wrote:

After reading a few articles, I can't quite work it out. Now I'm getting into my cycling a bit more...

What's the point in them?
Which one is more useful, if I was only going to get one?

And to buy, or not to buy, and if not, where else should my cash go to make riding more... data heavy...?

What do you want to gain from cycling? Are you just a leisure cyclist pootling along enjoying the scenery? If so, I wouldn't bother buying anything. Are you riding to get fit or want to improve yourself with a view to joining a club and doing some local TTs? If so then definitely, you'd find a use for speed, cadence, HR and later maybe even a power meter the further you become focused on improvements.

wildpig

philthy3 wrote:

What do you want to gain from cycling? Are you just a leisure cyclist pootling along enjoying the scenery? If so, I wouldn't bother buying anything. Are you riding to get fit or want to improve yourself with a view to joining a club and doing some local TTs? If so then definitely, you'd find a use for speed, cadence, HR and later maybe even a power meter the further you become focused on improvements.

Currently "leisure" - fit and active in other sports, gym, long distance running events etc, but I have some aims for next year, including completing a few 100 mile events, my first triathlon, and maybe an overseas bike tour.

I get the impression that knowing this stuff would help me improve faster? I use an HR strap for all other exercise at the moment and it's very useful.

wildpig

awavey wrote:

but that doesnt answer whats the point though

in a non professional, not training situation, as most recreational riders are Id say out of both I probably find real time cadence more useful on a ride, than really caring too much about how accurate the speed really is, certainly on a decent GPS device there shouldnt be much difference on the speed calculation.

whilst cadence, though you ought to be feeling in your legs anyway if you are churning too big a gear, though it always surprises me to see people still suffering doing it, you get to see real time whats your comfortable pace, & you know roughly the marks you should be hitting and can keep ontop of the gears with it, thats the point of it IMO

That does sound more useful than having data for the sake of it. Does cadence recording make a difference where it's placed, or is that device specific? I.e. are both crank arm/shoe as accurate as each other?

wildpig

wongataa wrote:

Usually the GPS speed is fine. But it can jump around a bit when you are cycling at a steady speed. A speed sensor prevents this. If you cycle in areas of reduced sky visibility (under tree cover, areas with lots of tall buildings, tunnels, narrow valleys, etc) the GPS speed reading can be unreliable. A sensor solves this. When cycling slowly up steep hills the GPS speed reading can be unreliable. A speed sensor solves this. If the GPS speed reading is unreliable the recorded distance will be unreliable. A speed sensor solves this. It is not a big issue but some people prefer the speed/distance readings to be reliable and as accurate as they can get.

I've also taken up MTB and downhill riding, so actually a speed sensor might be a good call. But then a post below you says cadence > speed. Interesting. They're not hugely expensive so I guess just buy both, track the data and see where to improve.

dinyull

Cadence, definitely.

I don't even have speed showing on my Garmin. Time, cadence and heart rate are the only variables I have showing. Allows me to monitor how hard I'm riding and when to eat.

wongataa

wildpig wrote:

awavey wrote:

That does sound more useful than having data for the sake of it. Does cadence recording make a difference where it's placed, or is that device specific? I.e. are both crank arm/shoe as accurate as each other?

I don't think there are any cadence sensors that go on shoes. The magnetless ones strap to a crank arm (they might work on a shoe) and the ones that use magnets are on the rear triangle so they can sense the magnet on the crank arm.

I use magnetless speed and cadence sensors. They work well and are very unobtrusive. The only time I touch them is for battery changes. I have cadence and speed shown on my Garmin. I like seeing both numbers.

StillGoing

wongataa wrote:

wildpig wrote:

awavey wrote:

That does sound more useful than having data for the sake of it. Does cadence recording make a difference where it's placed, or is that device specific? I.e. are both crank arm/shoe as accurate as each other?

I don't think there are any cadence sensors that go on shoes. The magnetless ones strap to a crank arm (they might work on a shoe) and the ones that use magnets are on the rear triangle so they can sense the magnet on the crank arm.

I use magnetless speed and cadence sensors. They work well and are very unobtrusive. The only time I touch them is for battery changes. I have cadence and speed shown on my Garmin. I like seeing both numbers.

Wahoo have some that go on the shoes, but I wouldn't rate them over crank based strain gauge ones.

chris_bass

yeah wahoo cadence sensor can go on the crank or a shoe - I found both wahoo's speed and cadence sensors to be hugely unreliable especially over ant+.

comparing rides on two different devices, one using GPS and one using wahoo sensors gave a massive difference. I think the problem comes when stopping they are quick to go into sleep mode and take a while to wake up again.

dinyull

Chris Bass wrote:

yeah wahoo cadence sensor can go on the crank or a shoe - I found both wahoo's speed and cadence sensors to be hugely unreliable especially over ant+.

I'm finding the Wahoo cadence sensor inconsistent. Have a quick look and will get readings from 50's - 90's whilst I'm happily tapping out a consistent 90+ rpm. Seems all over the place at times, especially compared to the Bryton unit I have on the commuter.

surfercyclist

I use these on my bikes, cheap and seem to work well. I do get spurious readings now and again so although my average over a ride will be say 85 rpm, it usually says I maxed out at 185 or something which definitely isn't correct! As I have a Wahoo Bolt I was going to get Wahoo speed and cadence sensors but seemingly they aren't any better or consistent so didn't. These are ANT+ and Bluetooth so good enough.

https://www.ebay.co.uk/itm/RPM-Speed-an ... Swy69ZrwEz

londoncommuter

On the really cheap front, I was pondering one of these but nobody had anything good or bad to say on here so I didn't get one:

https://www.ebay.co.uk/itm/CYCPLUS-IPX7 ... 2045034834

turbo_hamster

Speed sensor works on revolutions of front wheel, so it works indoors. I got a lot of use from mine when I was doing training sessions on rollers. The coach gave me hard efforts based on speed (and tyre pressure). He might have preferred to prescribe power-based sessions, but I couldn't afford a power meter - over £1000 at the time, compared to £50 quid for the speed and cadence bundle. Doing hard sessions by heart rate is not very effective, and I'm not so great at working by RPE.

chris_bass

londoncommuter wrote:

On the really cheap front, I was pondering one of these but nobody had anything good or bad to say on here so I didn't get one:

https://www.ebay.co.uk/itm/CYCPLUS-IPX7 ... 2045034834

I got something very similar to this from dx.com or similar to see what they were like, it is next to useless! i'd avoid! although came with a spare battery which was useful!

BikerGroveish

They give you actual data on your speed and cadence. The most efficient Cadence for whichever gear you’re in is 90 rpm. If you also have a speed sensor this tells you the speed you’ll be moving at at this peak efficiency for whichever gear you’re in. It will help
You get your riding as efficient as it can be and help with your training. Of course you can live without them. They aren’t totally necessary to ride a bike. But if there is a way to make your riding more efficient they are very effective.

svetty

BikerGroveish wrote:

... The most efficient Cadence for whichever gear you’re in is 90 rpm....

Cough 'b0770cks' cough.

Not all riders are the same. It is fair to say that a cadence of around 80 +/- 10 will suit the majority and give a reasonable spread of load between the legs and the cardiovascular system for endurance riding. To be any more authoritative than this is overstating things.

StillGoing

turbo hamster wrote:

Speed sensor works on revolutions of front wheel, so it works indoors. I got a lot of use from mine when I was doing training sessions on rollers. The coach gave me hard efforts based on speed (and tyre pressure). He might have preferred to prescribe power-based sessions, but I couldn't afford a power meter - over £1000 at the time, compared to £50 quid for the speed and cadence bundle. Doing hard sessions by heart rate is not very effective, and I'm not so great at working by RPE.

Front wheel? Surely you mean rear wheel. If you're on a wheel on turbo, you want the speed sensor on the rear hub, not the front where it will be doing nothing.

Although I ditched Garmin and moved to Wahoo, other than the Wahoo Tickr, I still use these. The P2M does cadence on the main bike though.

https://www.sigmasports.com/item/Garmin ... lsrc=aw.ds

BikerGroveish

Svetty wrote:

BikerGroveish wrote:

... The most efficient Cadence for whichever gear you’re in is 90 rpm....

Cough 'b0770cks' cough.

Not all riders are the same. It is fair to say that a cadence of around 80 +/- 10 will suit the majority and give a reasonable spread of load between the legs and the cardiovascular system for endurance riding. To be any more authoritative than this is overstating things.

Yep there’s a window. 90rpms give or take.

StillGoing

BikerGroveish wrote:

Svetty wrote:

BikerGroveish wrote:

... The most efficient Cadence for whichever gear you’re in is 90 rpm....

Cough 'b0770cks' cough.

Not all riders are the same. It is fair to say that a cadence of around 80 +/- 10 will suit the majority and give a reasonable spread of load between the legs and the cardiovascular system for endurance riding. To be any more authoritative than this is overstating things.

Yep there’s a window. 90rpms give or take.

Unless you've supporting evidence for that, I agree with Svetty. All riders are different and whilst a cadence of 80-90rpm produces less EMG, it does put more strain on the heart and lungs, which is why amateur cyclists slow their cadence down when tiring. If you're aerobically fit, then a high cadence makes sense. But if you're not, a lower cadence of 70-80rpm is going to be more efficient. If you watched the debacle TV program putting some Z list celebrities through e'tape, you'll have heard Dame Sarah Storey telling one of them that they needed to be doing a cadence of between 75-85rpm for efficiency.

imposter2.0

BikerGroveish wrote:

Svetty wrote:

BikerGroveish wrote:

... The most efficient Cadence for whichever gear you’re in is 90 rpm....

Cough 'b0770cks' cough.

Not all riders are the same. It is fair to say that a cadence of around 80 +/- 10 will suit the majority and give a reasonable spread of load between the legs and the cardiovascular system for endurance riding. To be any more authoritative than this is overstating things.

Yep there’s a window. 90rpms give or take.

Wrong. No single cadence range suits every rider.

BikerGroveish

Imposter wrote:

BikerGroveish wrote:

Svetty wrote:

BikerGroveish wrote:

... The most efficient Cadence for whichever gear you’re in is 90 rpm....

Cough 'b0770cks' cough.

Not all riders are the same. It is fair to say that a cadence of around 80 +/- 10 will suit the majority and give a reasonable spread of load between the legs and the cardiovascular system for endurance riding. To be any more authoritative than this is overstating things.

Yep there’s a window. 90rpms give or take.

Wrong. No single cadence range suits every rider.

Aha but it’s not a case of suiting or not. It’s just proven to be most efficient at the higher cadences. With the advent of relativey cheap power meters that have a strain gauge and a cadence sensor power can be used as a better guide. The higher you want your cadence in a given gear to be the harder you have to press. If you aim for a higher power but only have a cadence sensor to measure it aiming for a cadence of about 90 rpms give or take will mean that your power output will be at a level and for a duration that you can maintain with maximum efficiency. The power meter will measure both your cadence and your torque and give you a more meaningful metric with which to work as the number it generates will be measured from both parts of the equation. If you also have a heart rate monitor then you’ll have even more data with which to work.

https://fitrecovery.wordpress.com/2014/ ... ling-fast/

Here’s one article that explains it.

And here’s another

https://www.velon.cc/en/news/2017/01/ve ... -explainer

imposter2.0

FFS - if you are going to offer 'proof' don't just link to two websites containing nothing more than anecdote and personal opinion.

turbo_hamster

philthy3 wrote:

turbo hamster wrote:

Speed sensor works on revolutions of front wheel, so it works indoors. I got a lot of use from mine when I was doing training sessions on rollers. The coach gave me hard efforts based on speed (and tyre pressure). He might have preferred to prescribe power-based sessions, but I couldn't afford a power meter - over £1000 at the time, compared to £50 quid for the speed and cadence bundle. Doing hard sessions by heart rate is not very effective, and I'm not so great at working by RPE.

Front wheel? Surely you mean rear wheel.

You misunderstand. My speed sensor is fitted to the front fork and when on rollers or on the road (but not turbo as you point out), both wheels revolve.

svetty

Actually the research that has been done suggests that a lower cadence of around 60 is the most efficient wrt power output vs oxygen consumption. This does put more strain on the legs however and so riding at a higher - less efficient - cadence is more sustainable which is why the rate of 80+/- is usual.

navrig2

I have the Decathlon speed/cadence sensor on my turbo. It has been faultless for several years. I only used it on outside rides for a short spell tho.

BikerGroveish

Navrig2 wrote:

I have the Decathlon speed/cadence sensor on my turbo. It has been faultless for several years. I only used it on outside rides for a short spell tho.

I didn’t know they made one. Is it inertial or magnet across a sensor?

BikerGroveish

Svetty wrote:

Actually the research that has been done suggests that a lower cadence of around 60 is the most efficient wrt power output vs oxygen consumption. This does put more strain on the legs however and so riding at a higher - less efficient - cadence is more sustainable which is why the rate of 80+/- is usual.

It’s key to know what power you’re putting out at your chosen cadence range though surely? It’s not much good being able to sustain a high cadence if you’re only making a low power. I guess when you have a C.V. fitness level that allows you to sustain a relatively high cadence you should then be working on your leg strength and muscle endurance to allow you to put out increasing power at that cadence is the way forward. So effectively keep your cadence range constant and aim to increase power at that cadence by increasing the amount and duration of applied torque.