Gearing v HR v cadence v power

Ok, here goes lol… My dedicated trainer bike is Sora 50/34 by 11/32… Cassette is 11/13/15/17/19/21/24/28/32. On my 4DP I did my NM/AC in the 17 but a 16 would have been ideal had it been there, 15 was too much to spin up. In level 1 for it. Last night I did “Revolver” and that required (or advised, Erg mode didn’t seem to work anyway)…it was level 1( played with that during workout), but again these 2 teeth jumps around mid cassette seemed to play a big part in being unable to hit the 3 target zones, if I got the power right I was spinning too fast, if I changed up I was spinning too low and producing too much power or HR went too high… So, that’s the issues and one solution I’ve been thinking of is tucked away in one of my many spares hoarders drawers is a 14-25 cassette which has 14/15/16/17/18/19/21/23/25… I was going to put this on my road bike this coming spring( until I upgraded that to 105), by also removing the 18 or 19 and adding a 28 or 32 cog… Where I live is hilly and TBH in reality 50/14 is big enough on the flats and I don’t care about going flat out downhill… So this may offer the fine tuning element I need to get my targets in SYSTM? It probably would mean adjusting trainer difficulty downwards for rides in RGT to get up steeper hills and vice versa. Beginning to wonder if this is the reason Kickrs come with 11 speed 11-28 cassettes fitted, having the largely one tooth jump seems the optimum?? Any ideas folks and does anyone else run a 25t lowest gear( who isn’t super fit!)?

It can be a challenge to hit all the targets in level mode simultaneously. I tend to focus on power and hr and if the cadence is in the ballpark that’s a bonus.

The exception woukd be if very low cadence is called out (60-75 rpm) in which case i shift to a harder gear to get there. The perfect is the enemy of the good, so unless you really want to create a 1 cog spaced cassette I would just suffer with what you’ve got.


I run an 11s 11-25 on my old trainer so have the single tooth jumps you’re talking about. However, in level mode, I’m still rarely able to match both power and cadence. I 100% target the power target and then just get cadence in the rough ballpark. It’s either a spin interval or a grind interval. So if you’re out by 5-10rpm I wouldn’t think it’s too much of an issue, as you’ll still be in the rough ballpark. HR will likely still be close to zone. Don’t target HR either, it lags so much, and is irrelevant as a target for quick, snappy intervals work.
Target power
Then get cadence as close as you can. Being off the target by 10 rpm isn’t going to make much diff to HR either. A cadence of 90 vs 60 will but a cadence of 80 vs 90 won’t make much difference.

Longer intervals in Erg mode, target cadence, let the trainer manage power and keep an eye on HR. I often see HR as an indicator of getting sick, being tired etc, if it isn’t playing nicely. But do expect it to lag a bit behind the target zone, hearts accelerate and decelerate like an A380 not a Eurofighter on a flight deck.


Thanks for the replies, maybe should turn the HR off on the screen and run it on the bars on my Garmin watch so I can keep an eye on it but not have it in my face the whole time! I think I will switch out the cassette- I have a (one chain through it) 12-36 one that is more for MTB and IIRC it has the “evens” in the higher range (ie 12/14/16/18/21 etc) so may be able to merge the two for what I need without using the new 14-25. Wear on the TT should be far less than out on the roads so I suppose I could switch out cogs as I hopefully progress so I have say 4 or 5 a tooth apart (the ramps on them will probably be all over the place)… Good advice re sticking to the power though, need to just ensure I’m hitting that in “Level” as the priority then… ERG is different and I can start a workout hitting the power easily with the HR below where it should be but at the end of the session the “drift(?)” has got it to where it should be. Just have to watch for not upping the watts to start with to get the HR up asap…

I wouldn’t turn HR off. I just wouldn’t worry about it apart from a cursory “am I roughly moving towards being in zone or not?” It’s still useful as can tell you if you’re fatigued or getting sick. And likewise if you’re hitting the power and cadence targets but HR is staying low, it can indicate you need to re test.


Keep HR on screen as you’ll learn more about yourself but as said above, target power with a secondary consideration for cadence. You’ll rarely reach the perfect power and cadence in level mode so don’t worry about it, and concentrate on power.


What trainer do you have?

Kickr V5… Upgraded from the Snap, it was difficult keeping anything consistent on that I found ( disregarding human error lol)

Just stick it erg mode and go then, if you use the inner ring and mid cassette sprocket it should have no trouble with the power changes.

I used Erg at the start and the onscreen advice was do “Revolver” in Level. I was in ERG and wondering until that point why my rpm was fine in the warm up but way under the power… There’s about 6 or 8 workouts on Sufferfest that say only use level…

I’d love to have the HR graph overlain on the power graph during a workout (similar to Trainerroad, Zwift, etc). Would help monitoring trends during a workout.


A Guide to using ERG mode – Wahoo Fitness Support

Some smart trainers are better than others when it comes to ERG mode. If you’ve got a top-of-the-line KICKR, you can probably manage most of the workouts that are in the app, in ERG mode. There are some workouts that are best done in Level mode:

and then

Any workout where your trainer struggles to add or remove the resistance during the interval should be done in Level mode. As mentioned earlier, this will vary depending on the trainer that you own.

Unless your MAP is enormous your Kickr should be able to handle the resistance increases in ERG mode. When I do Revolver the interval power is more than 3x the recovery power and my cheapo JetBlack Volt has no trouble reacting in less than 2 seconds, It used to take 10seconds to change gear and wind up the cadence to get the rear wheel spinning on my old wheel-on dumb trainer.

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I’m about to do “The Shovel”… I’ll see what the first minute or two of the warm up says again but if I’m being asked to do say 80rpm at 110w and I’m doing the 80rpm but it’s reading 60w then I’m stopping and putting it in Level (like I did with Revolver)… As it says, ERG is good for steadier, longer cadence work but these are surely expecting you to go all out then change up as the flywheel speeds up and power starts to fade off?

Just change gear to reach the correct power targets. I tend to use two gears and big ring to get around the correct power for the harder efforts and just drop down to the small ring using the sane two gears on the easier bits. play around with it a bit and you will soon suss it out

I’m being asked to do say 80rpm at 110w and I’m doing the 80rpm but it’s reading 60w

Are you talking about the recoveries between the intervals? Its common for the power reading to drop below the target when you finish an interval and reduce cadence with the flywheel still spinning at high speed. I don’t think the power targets matter, as long as your legs are still pedalling you’ll still be clearing metabolites to get them ready for the next interval.

When in Erg mode don’t try to chase the power target, match the cadence target and the trainer will adjust resistance to match the target, you just have to give it a couple of seconds.

I have bluetooth keyboard connected to the iPad I run the systm app on within arms reach so I can jump in and out of ERG of mode.

My trainer has no problem with ramping up the power for short intervals down to about 15s, I leave it in Erg mode for most of the Shovel and switch to an appropiate level for the shortest efforts based on NM power. Like @ozmadman I just switch from big to inner ring for the recoveries on those intervals and don’t worry to much about the cadence targets.

Heres an example power graph of mine from the shovel done in Erg mode showing how well the trainer can keep up with the power changes. In fact I think it can do it faster than I can change gear ( my trainer bike has crappy Claris 8 speed)


Looks good! what trainer have you got?

JetBlack Volt EMS mk1, the one that Zwift Hub is based on, the one Wahoo is suing them over patent infringement. I’ve had it a year and been really happy with it apart from the V3.0 firmware (auto calibration) which was a disaster and they had to rollback.

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“I leave it in Erg mode for most of the Shovel and switch to an appropriate level for the shortest efforts based on NM power”
That’s exactly what happened this afternoon, erg worked brilliant but cannot cope with the 5s NM stuff as I found out, so manually switched it to level after/before the MAP sections after the first one went bonkers… Jeez, that Shovel is a workout alright… Clever and devious lol…:crazy_face: