Problem with cadence / spinning out


First post. Kinda new to all this and looking for help.

First off everything I am using is Wahoo! Kickr / Sufferfes / HRM and everything has set up fine from what I can see. I don’t think my problem is hardware or software.

Quite simply I assume ERG combined with my fitness level would broadly assist with the cadence I need to put out. I was often spinning wildly with no wattage being put out on Zwift and assumed it was a software issue. I am now on Sufferefest and its even worse. In the training programmes I am often way over or under cadence suggestions for the wattage required so end up trying to match one or the other. On the sufferfest ipad app I moved from ERG up one level ( I forget how its described) and that did not help so it seems that ERG is not set too low. As is probably clear from the post so far I really might be doing something fundamentally wrong as I have a lot of tech going on and have rather jumped in at the deep end. I assumed ERG handled ‘resistance’ for you

I have a gravel bike attached with SRAM Rival and my rear cassette is MAHOOOOSIVE. (11-42) and my current thinking is that is the issue?

Apologies for me extremely amateurish explanation of what’s happening. I hope someone can help



It sounds as though you have not got ERG set at all. The whole point of ERG is that it automatically sets the resistance and this varies depending not only on what the software is telling it but also by what your cadence is - the power required will stay the same whether you are pedalling at 150 rpm or 50 rpm but the resistance will increase as cadence decreases to maintain the same power output.

I assume that you have no other software or apps open. The Wahoo app for instance will interefere with Sufferfetst (in fact will ignore it completely) unless you have it in the pass through section (ie tell it to let other software control the trainer)


Hi @peterhaines,

Welcome to the forum. I’m sorry that you are having trouble. It sounds like you are in Level mode. You want to select the ERG option that shows up underneath your KICKRs name in the device connections menu.

Check out this help article.

If you are still stuck please reach out to the minions.

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@peterhaines I would also recommend taking a lot at this article: All About ERG Mode

As Sir Cody said, though, if you still have questions or need help please feel free to get in touch, we are always happy to help!


Hello and thanks for helping.

No im defintely in ERG mode! I also -seem- to be performing the cadence required, it’s not just being illustrated in the display as such.

I am in an unbelievably low intensity beginner mode based on my 4D thingy, could that be an issue?


On my kickr there is a range of gears what work for any given power. If it is set to ride at 80 watts and I am in the big ring, and middle of the block, I would be riding above the power required. If the workout calls for 200 watts and I am in small ring, big end of cassette, I would be spinning out trying to maintain that power. Assuming the minions rule out any sensor issues, would playing with gearing help?

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In ERG mode you should have full control over your own cadence while the power output remains constant. So if you pedal faster then the trainer resistance should automatically reduce to keep the power constant and vice-versa.

If your power output is changing with cadence then ERG is not working properly. You will always get some transient variation in power as you increase or decrease your cadence, but it should always settle to the ERG set power level after a few seconds pedalling at any specific cadence.

The only caveat is if your gearing is either too high or too low for the trainer to adjust its resistance within a suitable range to maintain your ERG power level. In a very high gear there will be a power “floor” that the trainer cannot go below and in a very low gear there will be a power “ceiling”. But if you choose a mid gear on your cassette I doubt you would run into these issues.

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As I understand, you are having this problem over a couple of software platforms? This might indicate a defective Kickr? Does your bike also have a power meter? A little off topic but I found that if power is assigned to my bike’s power meter rather than the training it does not work out well. My power meter assigned to cadence only…all good.

Yes this is correct and I actually believe I am doing roughly the cadence suggested but it is not being registered as such. In some situations. I am usually being advised that I am overspinning but in my last workout the sufferfest app suggested I was doing 40rpm which was no way correct.

I don’t have a power meter and ive never used a kickr or anything remotely like it before so im struggling to work out whats wrong. Is it likely that the kickr is defective? Is this a known issue?

Thank you!

This may not be directly related to the problem you’re having, but I would consider adding a dedicated cadence sensor. My Tacx trainer doesn’t always do a good job estimating cadence itself, so I use a Wahoo sensor on the crankarm instead. I’ve found it to be much, much more accurate.

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Use the ~ key on the keyboard to set erg mode.

If it’s too easy press the up arrow - this increases your targets 1%. Keep pressing until you feel like it’s “ about right”.

Down arrow decreases.

Do this for a while until you get the feel for it, then try a few rides on level mode. Numbers 1-9 will set the overall difficulty, and then your chosen gears and cadence will determine your actual output.

Once you’ve done this a couple of times and have the hang of it, do 4dp.

Lastly, get a dedicated cadence sensor. I’ve got a BKOOL pro and the cadence sensor is so bad it’s funny. Power seems ok on it, but can’t do fast switches. Better trainers would presumably be better at switching resistance faster.

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I have a similar problem, when doing a workout in erg mode often to match the power required my cadence it’s a bit off of the suggested cadence. This was particularly obvious in one of the GCN workouts up a mountain where we were asked to spin slowly, no way I would reach that power target spinning at that speed even though I changed gears.

Erg mode works perfectly on Zwift so I have been using Zwift for a while but looking into sufferfest still as I have a year’s membership for free.

I have a wahoo kickr core if that helps.

Thanks in advance

Again that sounds more like a trainer issue. Even at extremely low cadence (50 rpm) I can still maintain high power levels in ERG as long as I don’t use a very low gear on the bike, which then might max out my trainer resistance. My trainer is an Elite Direto X. Pretty powerful, but a Kickr should be similar.

Thanks for your reply, but if it a trainer problem why does Zwift work fine in ERG mode? The trainer is a couple of months old, so yes it might be a trainer problem.

Anyone else has any other ideas on what might be wrong?


I also have the Kickr Core. So if the trainer works fine on Zwift then maybe it is a gearing mismatch. ERG does keep power constant but there are a few gear/power/cadence combinations where it might have issues. As an example, for a workout like GOAT which is low cadence / higher power segments I am generally in 39/14 or thereabouts. For sprints (eg. Violator or The Shovel) I move to the 52 in front.

Unfortunately I have not done the GCN workout that you mentioned so I can’t comment further on what gears I used but based on the description it probably would have been similar to what I used for GOAT.

Have you contacted the minions?

My trainer (bkool pro) and I assume most, has a range of power that it can deliver for a given set of gears and cadence. So if I pedal in the highest gears at high cadence - it will generate several hundred watts even if the erg is set to 115. On the flip side, low cadence / low gears - it won’t hit the target. If zwift tells you it’s hitting it - then my suspicion is that it is telling you what power level zwift is asking the trainer to apply - but not what the trainer is actually reporting as the applied resistance.

So even in erg mode I know that for certain workouts and ranges I need to shift gears occasionally.

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Also some trainers have different profiles that you can connect to. Mine has two - smart trainer and dumb trainer. In smart mode it will change resistance depending on what the software tells it. In dumb mode it applies a standard resistance level, and the power output will be determined by your cadence and gear selection. Check with the support minions which one you need to choose, for your trainer.

Thanks, will do. Just been Zwifting a lot, so haven’t been on top of it but really want to give another attempt at Sufferfest.


I have been changing gears (on Zwift while racing, but not on the workouts in ERG mode that seems to be working well). I think emailing the minions is probably a good idea :slight_smile: thanks

I have the same issue. Level mode works fine and gives me roughly what it feels like ‘outside’ however on Sufferfest I have to drop gears so low to get the right power at the cadence suggested and even then I’m way over the cadence target. I did GOAT and it set my cadence at 50 but power was something like 185. Best cadence I could do was 65, not sure how I get it down to 50. It’s the opposite if I use my higher gears but then the resistance just drops completely and and I end up spinning out. I’ve read all the topics and sounds like everything is working but surely there must be something to do to test it or adjust the settings.