Alp de zwift resistance issue

Planning to do a vEverest, set the bike up to have a good range of easy gears. Rode yesterday with a 30-34 set up and was climbing the 10-13% doing 60- 65 Rpm and 2.5 to 2.7w/kg at 100% resistance. Perfect. Jumped on today and its now brutal, 40-46rpm to do 2.7wkg or 55rpm and 3-3.4 in the same spots. Was changing gears on the lower grades but today havent moved out of the 30-34! Same set up no changing any settings.
Running latests updates and on Saris H3 trainer
Anyone have this or why its happening?
It also happened the same way on a back to back climb, first climb good, second climb torture…

I did ride ADZ recently on June 21 and everything was completely normal using Kickr Bike - felt the same as any other lap on ADZ. Cadence around 70-75rpm, not really very high effort.

Day before I also did ADZ #146 at 52:13, also everything normal. June 7 also ADZ (#145) fairly ordinary.

Last time I did extra lap of ADZ after the first one was May 11 - that also seemed normal after I turned at the bottom.

I ride ADZ quite a lot and always in normal ride mode, never ERG mode so I’d notice if anything was amiss.

Im riding up col des Aravis on Haris H3 trainer 5:30am 25th June with Trainer difficultly at 100%, heroic level using 30-34 set up and sure enough 10% gradient im doing 2.7wkg, 62-65rpm at 13% 3.2wkg and 67rpm. So its definitely easier than yesterdays ride up the alp. So its not fatigued or a feeling, it could be the trainer? but not sure why 100% TD feels what i would expect then the next time it feels 150%???

Do u have the trainer difficultly at 100%? Ive never noticed a difference at 50% (normal) but since ive changed to 100% for the vEverest challenge ive noticed a variation in difficultly.

Always 100%.

Can you borrow a different trainer to test?

At 100% you’ll notice the gradient changes a lot more than with 50%, especially since the gradient changes are like a rollercoaster on ADZ while the real thing is just steady relentless steep gradients.

If you want an additional reference, try out Fulgaz and do the Alpe d’Huez climb with same 100% difficulty. Then report back how it goes.

I can only assume its my trainer, but cant see why it should feel easier one day and harder the next or even on back to back rides. Dont have access to another trainer so might just have to accept its varies… sigh.

Try it with another cycling app and see if it behaves differently. If the problem continues in other apps then talk to Saris support.

Try Fulgaz as a trial and do Alpe d’huez on that and see how it feels.

Or Col de la Bonette if you want something slightly flatter but longer to test your trainer. I’m thinking of that because you say this occurs on your second lap.

Because Bonette is 24km long with average 6.8% which should take you quite a long time - much longer than ADZ so you can see if it’s time related.

Make sure you have the uphill slope scaling set to 100%. You want to make sure your 12% gradient feels like 12% and not something less.