Shifting gears

I have the Kickr Core smart trainer. With this adjusting the resistance automatically in conjuction with the Systm, do I need to change gears, or can I accurately do workouts in one gear?

As a general rule, as long as you’re in ERG mode you are correct. You can keep it in one gear. Most folks go small ring, mid cassette to keep a nice straight chain line. Some workouts though, you may end up spinning out (super high cadence with relatively low power) and it’ll take the Kickr a couple seconds to readjust power based on flywheel speed.

For some workouts you may want to go small ring and large cog to minimize flywheel speed (I’m thinking here mainly of Cadence builds but there may be others).

Also, there are some workouts best done in Level mode where you will be switching gears as if on the road. The fitness tests, Full Frontal for example, should be done almost entirely in Level Mode where Half Monty has a mix of both.

So, what exactly is ERG mode?

Your smart trainer will adjust its resistance based on the “target” power from the workout and your cadence to give you a constant power output.

ERG mode is just what @titanicus says. Level mode is when you shift gears to change resistance just like you would out on the road. Read all about it, and SYSTM here:

And Level mode here:

This really helps explain it a lot, thanks. Aside from testing such as half monty and the other one, any other suggestions on workout types I should leave in level mode aside from ERG mode?

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Again the general rule is for efforts that are really short, you’ll wanna switch to level mode. So Violator, Half is Easy, the half is easy part of Revolver is easy. I use a Mac mostly and there are keyboard shortcuts that allow you to switch from Erg to Level mode on the fly. It’s pretty awesome. I’ll do that for the really sprinty intervals of the Shovel, where I’ll switch to level then back to Erg for the rest of it.

Edit: also @Hurlbut in the article I linked to above on Erg mode they provide a list of what workouts are best NOT done in ERG mode

“ When to use ERG mode/ When NOT to use ERG mode

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:


The Shovel

The Tool Shed

The Cure

Half is Easy

Cadence drills

Do As You’re Told (this will depend on your trainer)

Full Frontal (this should NEVER be done in ERG mode!)

The second half of Half Monty is also a Level Mode-only workout.

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. ”

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In ERG mode (2016 vintage Kickr), I find it useful to shift to one lighter gear in a couple of circumstances.

I sometimes struggle to keep my cadence up for moderately hard efforts. As I get tired, the cadence starts to gradually fall. So, I make harder efforts to lift the cadence back up. I have found that dropping to one lighter gear helps me spin back up. Shifting lower causes the resistance to drop by a few watts for a few seconds.

Also, when riding a moderately hard effort after fatigue has set in, the workout may call for a hard interval. It is necessary to lift the cadence for the higher power level. I have that shifting to one lighter gear as soon as the hard interval starts (i.e. power starts to increase) assist me with raising the cadence.

…maybe I need to do more of the cadence drills to address this weakness.