# Flux S / Indoor Trainer on ERG Mode **URL:** \ **Category:** Equipment\ **Tags:** trainer\ **Created:** [March 10, 2020, 12:55pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223 "2020-03-10T12:55:54Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![pmckendry87](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pmckendry87/32/7725_2.png) [@pmckendry87](https://www.trainerroad.com/forum/u/pmckendry87)\ **Post date:** [March 10, 2020, 12:55pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/1 "2020-03-10T12:55:54Z")
Hi All, I have a flux S - i’ve had it about a year & did some training on it but never structured and not a huge amount of training at that… Recently I started training consistently on TR… however, I have noticed that when pulling up to higher thresholds +290 watts… the trainer only seems to hold the power for a short time at a given cadence. In order to maintain the power output I seem to have to change gears otherwise I am spinning at 120+RPM to maintain the correct power to complete… Is this an amateur error or a trainer issue? Or can someone provide guidance on how I can fix this… thks! ---
**Author:** ![PusherMan](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pusherman/32/4266_2.png) [@PusherMan](https://www.trainerroad.com/forum/u/PusherMan)\ **Post date:** [March 10, 2020, 1:06pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/2 "2020-03-10T13:06:57Z")
Have you calibrated the trainer and do you calibrate it often? If not, I would calibrate via either the TR software or the dedicated TACX app. If that doesn’t resolve the issue, I would download the specific workout files and contact TACX (Garmin) directly. My Flux S started to have a similar issue and it was eventually replaced. ---
**Author:** ![pmckendry87](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pmckendry87/32/7725_2.png) [@pmckendry87](https://www.trainerroad.com/forum/u/pmckendry87)\ **Post date:** [March 10, 2020, 1:12pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/3 "2020-03-10T13:12:55Z")
Thanks @PusherMan I calibrate ever time before I train with the TR calibration so it rules that out. Sounds like it might be a trainer issue… I was hoping it wasn’t this. I’ll try contacting Tacx… thks ---
**Author:** ![Haveyoumetzach](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/haveyoumetzach/32/12890_2.png) [@Haveyoumetzach](https://www.trainerroad.com/forum/u/Haveyoumetzach)\ **Post date:** [March 10, 2020, 1:15pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/4 "2020-03-10T13:15:33Z")
Are you in a really low gear? I have a flux S and usually use it in a pretty low gear, and if I know the session is going to be 300+W for me then I usually go up a gear. I might be way off base here, but I think trainer’s have an upper and lower threshold for the amount of resistance they can apply to the flywheel so I don’t worry about it too much. I just try to be in the right gearing before the workout. If you’re in a higher gear and things aren’t stable, then I would go to Garmin. ---
**Author:** ![pmckendry87](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pmckendry87/32/7725_2.png) [@pmckendry87](https://www.trainerroad.com/forum/u/pmckendry87)\ **Post date:** [March 10, 2020, 1:21pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/5 "2020-03-10T13:21:22Z")
On the big ring & in the middle cassette… I have to jump 2-3 gears to try and bring down the spinning. Also I have noticed… I have to drop to the lowest gear on the back cassette to hit the suggested cadence between sets or threshold WO to try and get a smooth transition of power between the jumps… is this normal? thks ---
**Author:** ![PusherMan](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pusherman/32/4266_2.png) [@PusherMan](https://www.trainerroad.com/forum/u/PusherMan)\ **Post date:** [March 10, 2020, 1:34pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/6 "2020-03-10T13:34:17Z")
> [@pmckendry87](#): > > Also I have noticed… I have to drop to the lowest gear on the back cassette to hit the suggested cadence between sets or threshold WO to try and get a smooth transition of power between the jumps… is this normal? thks I certainly didn’t start changing gears, regardless of the session. I think that totally negates the purpose of ERG. ---
**Author:** ![PhilippePhlop](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/philippephlop/32/25540_2.png) [@PhilippePhlop](https://www.trainerroad.com/forum/u/PhilippePhlop)\ **Post date:** [March 10, 2020, 1:42pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/7 "2020-03-10T13:42:21Z")
On my tacx vortex i have to change gears. In the mid 200s effort vs resting intervals… im on the big ring, and will do work at the middle of the cassette. When it’s a recovery interval (close to 100w) i have to shift down on the cassette otherwise i’m recovering “too high” and if i stay in that cassette gear for the interval then i have to spin a looooot ---
**Author:** ![Crownan](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/crownan/32/103116_2.png) [@Crownan](https://www.trainerroad.com/forum/u/Crownan)\ **Post date:** [March 10, 2020, 2:47pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/8 "2020-03-10T14:47:18Z")
> [@pmckendry87](#): > > Recently I started training consistently on TR… however, I have noticed that when pulling up to higher thresholds +290 watts… the trainer only seems to hold the power for a short time at a given cadence. In order to maintain the power output I seem to have to change gears otherwise I am spinning at 120+RPM to maintain the correct power to complete… This sounds like you’re hitting the trainer ceiling. > [@pmckendry87](#): > > On the big ring & in the middle cassette… I have to jump 2-3 gears to try and bring down the spinning. If you’re in that hard a gear then that doesn’t sound right. > [@pmckendry87](#): > > Also I have noticed… I have to drop to the lowest gear on the back cassette to hit the suggested cadence between sets or threshold WO to try and get a smooth transition of power between the jumps… is this normal? This sounds like your working above the trainer floor, which is common. > [@PusherMan](#): > > I certainly didn’t start changing gears, regardless of the session. I think that totally negates the purpose of ERG. Kind of, but as above its very easy to hit the Wattage floor/ceiling if you’re not in compliant gearing. > [@PhilippePhlop](#): > > On my tacx vortex i have to change gears. In the mid 200s effort vs resting intervals… im on the big ring, and will do work at the middle of the cassette. When it’s a recovery interval (close to 100w) i have to shift down on the cassette otherwise i’m recovering “too high” and if i stay in that cassette gear for the interval then i have to spin a looooot I used to do this on my Tacx Smart, it didn’t have the range to accommodate big wattage jumps. I then moved to the Vortex and as yet haven’t had to change gears but I haven’t had any huge stomps yet 🙂 ---
**Author:** ![pmckendry87](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pmckendry87/32/7725_2.png) [@pmckendry87](https://www.trainerroad.com/forum/u/pmckendry87)\ **Post date:** [March 10, 2020, 4:57pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/9 "2020-03-10T16:57:22Z")
On average what is the best gear to run on to avoid these issues? ta ---
**Author:** ![PhydomiR](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/phydomir/32/94443_2.png) [@PhydomiR](https://www.trainerroad.com/forum/u/PhydomiR)\ **Post date:** [March 10, 2020, 5:37pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/10 "2020-03-10T17:37:46Z")
This should explain things a bit: [Garmin Tacx Indoor Bike Trainers](https://tacx.com/erg-training-flux/) ---
**Author:** ![Crownan](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/crownan/32/103116_2.png) [@Crownan](https://www.trainerroad.com/forum/u/Crownan)\ **Post date:** [March 11, 2020, 10:38am UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/11 "2020-03-11T10:38:04Z")
That is a very good explanation! ---
**Author:** ![Crownan](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/crownan/32/103116_2.png) [@Crownan](https://www.trainerroad.com/forum/u/Crownan)\ **Post date:** [March 11, 2020, 10:40am UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/12 "2020-03-11T10:40:43Z")
> [@pmckendry87](#): > > On average what is the best gear to run on to avoid these issues? ta That depends on you really, your typical cadence and your power needs. In some cases you may not be able to do the workout EXACTLY without the odd gear flick. ---
**Author:** ![pmckendry87](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/pmckendry87/32/7725_2.png) [@pmckendry87](https://www.trainerroad.com/forum/u/pmckendry87)\ **Post date:** [March 12, 2020, 1:37pm UTC](https://www.trainerroad.com/forum/t/flux-s-indoor-trainer-on-erg-mode/31223/13 "2020-03-12T13:37:49Z")
Really good article thanks @PhydomiR “With the FLUX Smart it is possible to perform these kind of workouts. This trainer can produce a certain range of power levels for a specific gear setting (illustrated by the blue shape in the graph below). In case your riding at the top of this range and you wish to increase the power or when it’s at the bottom of this range and you wish to lower the power, **you have to shift gears**.”