How to Tunnabora on a dumb trainer?

The instructions for Tunnabora are to increase your cadence as the power target falls. I ride a dumb trainer with a Stages LHS power meter. Obviously spinning faster equals more power, and if I change down one gear it’s too big a jump and I have to go from 85rpm to 100+ rpm to hit the first step.

Am I missing something, or is there no really good way to follow the workout instructions on a dumb trainer?

What I usually do is the inverse and let my leg speed decrease as target power does. I figure I’m still getting some lower cadence work so there’s some benefit in that.

I don’t think there is a decent way. I’ve seen it somewhere, probably one of the workouts, that says the cadence values are for ERG mode.

I’ll change down a gear but I don’t get anywhere near the difference in cadence that you do, maybe 7-10rpm at most.

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I used the power as an approximate target and focused on hitting the cadence recommendations. For the second and fourth steps, just increase cadence; for the third, gear down one.

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What trainer and cassette (assuming you are talking about a single shift on the rear derailleur) do you have that leads to such a big jump in cadence change?

I typically just ignore that suggestion, it leads to too much tinkering with my gears and not enough attention paid to the workout if I try to follow it strictly.

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from 85rpm to 100+ rpm to hit the first step. **

** might not be scientifically accurate.

I remember it being too big a jump to hit the numbers. I’m about to head out to the shed now and give it a whirl, hence the original question. I’ll make not of what gear, RPM and Watts I get if I try to gear down and rev up.

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I like my triple ring 9-speed road bike I mainly use on the trainer for this aspect since my cassette is very tightly spaced and I can typically do these incremental changes - - sometimes there’s just no getting things to line up perfectly though. At least it’s not like when there are cadence targets on Zwift workouts and you “fail” the interval if you don’t hit it (I usually have more trouble hitting the really low cadences even maxed out on gears and my KK Road Machine roller cranked down).

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Yea, ok. Zero science to be had here.

The last time I did Tunnabora was back in August, with an FTP of 256, on a 11-28 10 speed cassette. I’ve now got an FTP of 276 and I’ve put an 11-25 on the bike, the trainer has remained the same, Tacx Satori (the old dumb one) on level 4 and the same 50-36 up front.

I’ve gotta say, the stepping felt really good, I started out in the 50x17 @ 82rpm, then worked through the 19, 21 and 23 into the valleys of the workout at 86, 91 and 97rpm respectively and it worked pretty well.

Too much has changed to be truly objective but I recon the tighter cassette has made the difference compared with the bigger jumps of the bottom end of an 11-28.

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We could do a comparison with gearing to identify input / output with the different cassettes. But I don’t think there is much to gain from it considering you have a nice and tight cassette now, and it gave you great results.

Glad it workout out regardless of the specifics :smiley:

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If “85 to 100+” is about what it feels like and not accurate – I can agree. I was using a Kurt Kinetic Road Machine and 11-32 gearing (11-speed), and one shift in the rear was a pretty significant jump. In general, it was coarse enough that for any workout I had to either get the power right or get the cadence right, and just do a best effort on the other of the two.

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I installed a very close-range 14-25 “youth racing” cassette on my trainer bike, and it has helped somewhat with this issue.

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I’m pleased to see gregbuk post this query. I’ve just tried the Tunnabora on a Tacx Satori and I encountered the same issues and dealt with them in the same way. It’s good to know that I wasn’t missing a way of following the workout. I had the added problem that my bike is only 9 speed, (11-28) so has large steps between the gears.

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Before changing this workout to an outside workout, I was looking at the details and thinking, “how am I going to do this one outside?” After the change, looks much easier to do with a range. Find out tomorrow.

Based on my past comments, it was fun to do, but that was in erg mode.

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