MegaSack DRAW - This year's winner is user - rgwb
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I've got a wife unfriendly problem with my Zwift setup.
Over the past few years I bought first an Elite Kura (secondhand) and in lockdown an Elite Drivo II (secondhand also). Why Elite? Well come with straightforward proper through axle fitment and don't clash with long rear mech cages; I'm riding it on my boost spaced mountain bike.
The Kura has the accurate Elite power meter but is a fluid trainer so isn't "smart" and can't do erg mode or slope simulation. Pedal faster/change up a gear and power goes up (to unfeasibly large numbers). Uphill/downhill in Zwift makes no difference. Turn the cranks and the power number turns up on the screen.
My Drivo II works like a dream on erg mode for structured workouts. In simulation mode it works great when you're slogging up an Alpe. But the mountain bike front chainring doesn't turn it over fast enough to soak up enough power on simulated flat road conditions because I'm stuck with a 32T chainring. Zwift's "trainer difficulty" setting doesn't fix it because it just makes things harder on the hills.
Wife expectation is a single trainer and no more bikes. Is there a setting to get the Drivo providing enough resistance on the flat? If not I'm probably going to have to get rid of it.
is a single trainer and no more bikes. Is there a setting to get the Drivo providing enough resistance on the flat? If not I’m probably going to have to get rid of it.
There isn't, you're only generating as much power as you're generating. trainer difficulty - as you've rightly pointed out - only increases the "gearing" of the hills, it doesn't make it harder, you just end up using lower gearing to climb and higher gearing to descend.
Either you need to spin faster or put a bigger chain ring on.
You could maybe try changing your wheel size in the drivo config - I've not played with it but theoretically doubling your circumference might significantly increase the gearing on your trainer to account for the bigger gear inches.
You could maybe try changing your wheel size in the drivo config
Why does a wheel off trainer care about wheel size ? And more so why would it take that into any calculation to derive from a direct power reading. ?
Not got an elite trainer but just don't see the why.
But yeah power is power. In zwift your not applying resistance your working to a power for a given terrain.
You probably need to operate it in dumb mode and apply your own resistance through the elite app
You need a bigger chainring but I suspect you will get instances where your biggest gear isn't enough and limits your power output, or ideally a new bike (perhaps just for turbo?) that has 2x setup with a big ring near 50T.
Or concentrate your turbo efforts on ERG workouts, accepting freerides and races will be limited by the gearing.
crappy old frame with a road chainset on it. You know it makes sense
You used to be able to pick up old bikes at council tips - not so sure any more. I "saved" a street-dumped cosmetically awful mtb frame on recycling collection day recently. As long as the reach is right you can have as long or short a spem as fits, since you're not going to ride it (also no need of brakes, smooth headset etc)
If you're very different sizes, frame to fit the smallest of you and a nice long seatpost. If the fork has a long enough steerer you could have 2 stems w bars at different heights/reaches (- we should all be more Sheldon !) but one of you will get custody of the shifters. Alternatively, you might get away with clever use of an adjustable stem but I think that'd become a PITA
I managed to get a 40T onto my Parkwood, which mostly worked ok... but then when you want to take it outside you need to change he chain-ring.
Think I may have found the wife friendly option.
https://www.merlincycles.com/3t-overdrive-cassette-11-speed-180155.html
Fits the Elite XDR cassette body (which I have); 11speed (which I have). I'm currently on an 11t, so whatever power the trainer resists at my current 110rpm I'd get at 90rpm. It is a jump from that 9t up to the next 11t cog, but it may be all I actually need.
Failing that I may reach out to Elite and see if it is a parameter they can hack. They've been really good in tuning up erg mode on my trainer to be super responsive. I reckon the controller must already have the logic for "Zwift asks for X so stepper motor does Y" and slope simulation is just an open loop control so a zero-offset parameter that's hackable would be a likely part of the implementation.
Change bike on Zwift? If you use an mtb, then it increases the drag quite significantly, therefore needing lower gears.
Zwift is meant to be a simulation - what you are asking it to do is be less realistic!
Why does a wheel off trainer care about wheel size ? And more so why would it take that into any calculation to derive from a direct power reading. ?
Very much a guess but it might work on the basis of how much "basic" resistance the trainer offers.
Eg a 1000mm circumference wheel offers half the "basic" resistance of a 2000mm one such that two full revolutions of the smaller one requires the same power input as one revolution of the larger.
It's very much a guess but there's no reason the trainer can't effectively mimic the increase in gear inches from a smaller to larger wheel.
It's an easy seeing to charge and find out anyway.
Zwift is meant to be a simulation – what you are asking it to do is be less realistic!
It has the same basic rules like gravity. What you must learn is that these rules are no different than rules of a computer system. Some of them can be bent, others can be broken.
Downhill on Zwift acts at 50% of the actual gradient when at 100% trainer difficulty, allowing you to apply power and descend quicker for longer. At some point though, when travelling at 50kph+ on a 6%+ gradient, it's better to simply stop pedalling and allow the "supertuck" aero position.
Very much a guess but it might work on the basis of how much “basic” resistance the trainer offers.
I thought of that and tried it. Doesn't work. I think it is just a low-grade "cosmetic" feature for the Elite myETraining app so that in "level of difficulty mode" (i.e. direct control of the stepper motor) you can get a kmh number that feels right for you.
It has the same basic rules like gravity. What you must learn is that these rules are no different than rules of a computer system. Some of them can be bent, others can be broken.
All that inclusive I still think your using a screw driver to fit a nail.
To test the point I just took part in one of this evening's sprint races. Cat B. Flat course.
Rode the whole race in 32t/11t. 115rpm off the line to get the power down to stay with the bunch. Middle of the race was OK with 90-100 rpm in the bunch and occasional bursts when someone stretched the pack out. 120rpm to get 670W starting the sprint finish but then faded to 450W at 116rpm.
Honestly this was a lot better than I thought. The rpms are high and I could imagine a few extra watts being more sustainable at more sensible rpms. Maybe in a longer race it would be more telling. It would be nice to kick out in a high gear starting a sprint instead of winding up already fast spinning legs.
So not a disaster and it might be OK for everything I intend to do with Zwift.