This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Trouble with distance on a treadmill

Former Member
Former Member
Morning folks. I searched the forums here and did not find my exact problem so creating a new thread. Sorry if i missed something.

I'm a beginning running and recently switched from the fitbit surge to the Garmin 235 to hopefully take advantage of some of the running functions on Garmin as opposed to Fitbit.

Since switching it has been cold and raining where I live so have not had the opportunity to run outside and it appears it will be another week or so before I can. With that being said I do 90% of my training on a treadmill anyway. I am 5'10 and have a very standard stride length so generally any watch I have ever used captured my treadmill runs relatively accurately or at least close enough for my needs. My surge would generally be about a .10 of a mile ahead if I was walking/ jogging up to 5.5 mph and anything over that it was generally about .25 behind the treadmill. The gym I go to has some serious runners (not me) that use it so the treadmills are inspected and certified more often than I imagine most are.

So when using the 235 this week my numbers are insane. Tues and Wed I did my normal week day runs which is a 1 mile warm up at 5.5 mph then a 5K with intervals ranging from 6.5-8 mph then a 1 mile cool down at 5.5 mph. when I would do this with my fitbit it would generally end up showing about 4.8 miles as opposed to the 5.1 I really ran. Not a huge deal and even with a inspected treadmill I get that a .3 difference is not the end of the world and at least it was under as opposed to over. My 235 on the other hand showed both days at 6.5 miles and showed me running 6 minute miles. If only that was true. so a couple of questions:

1. is this the best I can expect for indoor training unless I buy a foot pod?
2. if I run outside will the watch be better able to track my indoor runs?
  • As you do more outdoor runs the watch will adjust to your stride and you should get better results. However...

    In my experience what will happen is that you'll find a certain sweet spot where the pace/distance is pretty accurate but slower and faster paces will vary.

    I use a calibrated foot pod when I use the TM and it works very well from about 10:00 min/mi down to 8:00 after that it starts reading a little fast. When I forget the pod and use the watches accelerometers it's consistently fast.
  • I wasn't aware that it learns from your outdoor running but that makes sense ... I ran dozens of 5k runs before I first used a treadmill. I've only run several times on a treadmill (I hate it, but sometimes necessary on those awful weather days), and it is scary close to actual distance, sometimes virtually exact!

    Max
  • I've never had great luck with any Garmin watch on a treadmill and I've never wanted to pony up the money for a footpod. I've played around with them enough over the years, and it does seem to get more accurate the more you run outdoors. The accuracy is pretty good on a treadmill if I keep my pace consistent and around my "easy" pace. However, anything outside of that pace can be off anywhere between .1-.25 per mile. I usually just edit the run in Garmin Connect with the correct mileage after I upload the activity.
  • Former Member
    0 Former Member over 5 years ago

    I am having this same problem, but I switched from the Garmin Forerunner 35 which was treadmill accurate, to the Forerunner 235 and now it says I run 7+ miles when the treadmills shows 5... even when I manually entered my stride length i did a 2.6 mile treadmill run and the Garmin showed 3.8. Do we have to calibrate each watch outdoors before it will work properly indoors?

  • yes you will want it on auto-stride length and run outside a couple times.  Ideally on a fairly flat area with good footing (not off road or on snow/ice).  Sounds like you run indoors typically?  Good to do the run at around the paces you typically run on the treadmill... and a few other faster/slower paces for a while.  This is so it can create an index of your pace and cadence relationship at various speeds.  

  • Former Member
    0 Former Member over 5 years ago in reply to NickMN

    Actually, i normally run outdoors, but my running partner had a knee and wrist injury a few weeks back, and generally prefers the gym anyway since we are different pace. My previous Garmin had no problem with the treadmill, and it was set to auto stride length. I recently got this new one, and assumed the stride data would transfer to this watch, but you are saying that is not true? That seems really inefficient.