Optimistic up a mountain... calculate lenght of ride

So as a fairly new Zwifter I just discovered how I can get the bike with the neon-light pimped wheels (Tron Bike) - its just to climb some hills. So far I have been doing mostly “flat” tracks, and I have got a feeling that on my spinbike with Power pedals I do about 30 km/h on flat tracks in Zwift. So today I had a couple of hours and saw this French mountain - only 20 km, but 1500 m/high… So I thought optimisticly “20 km… it should be possible in a couple of hours” - but how wrong I was!

During the ride I started to think and calculate - if its 9%+++ hill upwards, I only have 4-6 km/h, and then 20 km takes 3-4 hours… which is probably right with the watt input, so here is the question:
If I keep my flat 30 km/h “speed/watt/cadence - input” the whole way and don’t adjust the resistance on the spinbike - how much “longer” is the ride if there is a mountain track on 1000 or 1500 meter? Today 1,5 hr would normally give 50 km +, but I only managed about 12 km up the mountain and the last 8 kilometers I have to try again next time… So how do you calculate the time you will use if there is a mountain compared to a flat route? I can’t be the only one who has met the wall on a mountain… And is there a chance to countiniue on the same path from where I stopped next time?

(I hope this was understandable😊)

"If I keep my flat … “speed/watt/cadence - input” is never going to work. Speed and watts are linked, but the way they are linked varies with the gradient.

Guessing your weight (I won’t say what figure I used) rolling along on the flat as 30km/h takes 160 Watts. On an average 8% slope, that will only give your 6km/h. To be doing 30km/h up that slope you need to sustain over 820 watts. So lets say that 40 minutes is not currently on the books.

Climbing, especially long climbs, is purely a power challenge - what power can you sustain for long periods. But Ven-Top and Alpe du Zwift are the top climbing challenges, the ones you work up to/train for so don’t give up just yet. Instead start with regular rides like the Epic KOM (Watopia) and Box Hill (London) and slowly improve your power.

The figure most people track is FTP, and Zwift will tell you what it thinks your current FTP is. From my many rides up Alpe du Zwift, I know that to do that 12km 1000m climb in about an hour I need a FTP of 280 (for my 90kg frame).

So train on those smaller but still challenging hills and watch the power until you can see that your able to hold 240W plus for a long periods. Then you’ll be in the area to do things like Zen-Top in sub-2 hours.

ps. and Zen-Top is really a horrible long drag of a hill that even bores many people who can climb well.

Thank you! Did you calculate my 83 kg right? How do you do the math around this - for 160Watt and 820 watt?

And if you going for the Tron Bike make sure you have the Climb Mt. Everest challenge selected.

No and yes.

No, there isn’t a feature on Zwift where if you save your ride you can then continue where you left off.

Yes, there is a way you can do this. But it relies on you leaving the Zwift session running. For example, on any ride you can easily stop pedalling and go for a comfort break, make a cup of tea/coffee, and come back and start pedalling again. The only question is how long this gap can be. You could leave your avatar at the side of the road and come back to it the next day and carry on pedalling, and it will be ok as long as the Zwift session is still running. You might need to re-pair your trainer/sensors if they have turned themselves off. On a device that you only use for Zwift this should be easy enough, e.g. on a laptop that’s permanently set up for Zwift. Though on a phone or something else where the apps could get terminated through inactivity then it’s more risky.

Having said all that though, if it’s the Tron bike that you’re after then you don’t need to do any of that, and starting again each time won’t make any differences, since it’s just elevation gained that’s counted. It’ll only matter if you’re bothered about getting to the top and route badges (and the Alpe du Zwift prize wheel).

As said, for the Tron bike make sure you’re doing the Everest challenge, otherwise any climbing you do doesn’t count towards the bike. And that means staying on the Everest challenge even when you’ve completed the summit.

But if GPLamma is correct, just completing any of the OVS ride events running this month will give you a bike as good as the Tron for climbing.

I won’t say what weight I used. Or what your height and build are or what bike weight, which are all part of the calculation.

We don’t know exactly what model Zwift use, but they are trying to mimic the real world and the calculations for that are well known but complex (I use An interactive model-based calculator of cycling power vs. speed).

I just plugged in some guesses until I had a rider doing your stated 30kmh on the flat and then 6kmh at the same power on an 8% climb.