Comparing Garmin FTP estimate with Ramp Test?

Has anyone seen major discrepancies between their Ramp Test results and the FTP estimate on their Garmin? I am fully aware that the Garmin merely provides a rough estimate and is less scientific than a dedicated test, but the Garmin is coming up with values about 30-40 watts higher.

A little background: I’m a non-racer who has been riding outside all summer, and I’ve seen my Garmin estimate slowly creep up as my fitness has improved. Now that I’m integrating the trainer inside back into my rotation, my first ramp test ended up being much lower than I thought. I’m going to recalibrate my Flux and give it another go this week to see how much of it was my lack of preparedness for the test, but I was curious if anyone else has seen large gaps in these FTP values like this.

As long as I do some harder efforts the Garmin estimates close to my 20 min tested FTP. I always ignore it but it’s close…within 5 watts usually. I have a friend that also sees the same thing although he ignores it as well. Take another test.

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Yeah, the test was already on the schedule. The odd thing is, doing a couple of workouts at the higher FTP value from my Garmin was still feasible, so maybe I’m just that bad at testing. We’ll find out this week I suppose. :man_shrugging:

It sounds like you have multiple variable going on:

inside power meter vs. outside power meter (different devices can easily be 20-30 watts apart)

inside vs. outside (people usually make more watts outside)

Other than it strokes your FTP ego, I’d ignore what Garmin estimates.

I have a Fenix 5 and a 530. After hundreds of rides with both I find no value in the FTP estimate from Garmin. For me it is chronically low relative to my 1 hour FTP test, 20 minute FTP test, 8 minute FTP test and TR Ramp test. All put me roughly in the same spot whereas Garmin usually is 10-35 watts lower. I stopped looking at it after I won a race with a pretty big field and set all kinds of power PR’s. When I hit end ride my Fenix 5 greeted me with the “We have detected a lower FTP would you like to accept?” That was the beginning of the end for my faith in Garmin’s FTP estimate :joy:

Adding no value to your post but posting this anyway - I’ve never worked out how to get Garmin to estimate my FTP…it always shows “no value”.

Fair point, but no ego here. I feel out of my element on this forum sometimes as a non-racer, and I just want a baseline to see improvement.

The trainer and my power meter are pretty spot-on during the ramp test and other workouts as well. If it was a power difference I imagine I would be seeing that all the time, not just in the final values.

I’ll reassess after the next test and see how much of it is me being bad at the ramp.

choose whichever is higher! :wink:

I would try to use one power meter for all measurements. On TR you can use power match so it gets power from your power meter.

You may just put out more watts on the road. That is common for many people.

The other option is to do a 20 minute test and see what you come up with.


Both Garmin and ramp tests are bad estimates of FTP but may be useful in tracking progress. If you want to know with accuracy what your FTP is, why not do Kolie Moore’s test?

That is so weird, I only have a 530 and before that a 520. On longer tests like 20-min or 30-min or longer, the 520 and 530 were always within a watt or two of the other estimates. The ramp test has been the real wild card, its been mostly hit but enough misses that I don’t bother with it for FTP estimates.

The ramp, 8-min, and 20-min all have a range - for example if you are highly anaerobic and do the 20-min test then a lower multiplier something like .9 or .91 or .92 is likely more accurate than using .95 multiplier. Same is true for the ramp, although in my own experience the multiplier covers a much wider range and is therefore less reliable for FTP although ramp does give a good ceiling on 5-min vo2max power.

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