Originally Posted by Chris
Only two things I'll add to this -
1) adjustable resistance trainers can be used with Zwift... But only in a particular resistance setting. Switching out of that fucks up the power output estimation alogrythm, which is driven by wheel speed.
2) I still have my old alloy Allez... and I STILL use my Tarmac (and occasionally my Diverge) on the trainer. I wouldn't worry about it at all. My brother worries a little that his sweat may have corroded through the clear on his own Felt from all the time he spent on the trainer just dripping on the thing, but he's not positive and either way I'd just make a point of wiping your bike down when you get off.
Originally Posted by Chris
IMO, Zwift actually isn't far off... It's definitely slightly
fast compared to real life riding, but I'd say within ~1-1.5mph as far as the actual modeling goes. I think, IMO, the bigger difference is the fact that on Zwift you never, ever, ever have to stop or hit your brakes, while in real life that's never the case.
The fastest ride I've ever done in real life was just shy of 21mph: https://www.strava.com/activities/1812815337
...on a bike path with almost no one on it and only a few crossing points. Without those (and the couple meandering in the middle of the trail paying no mind to anyone that brought me to a dead stop as I reached them just as I was passing two other riders), I'd have been in the 21-21.5mph range.
This isn't my fastest
Zwift ride, meanwhile, but it's close, and the most comparable (the faster ones were generally shorter, in a group even where I was benefitting from drafting, or both - the Tour of New York stage 5, for example, was a 32 minute, 12.6 mile sufferfest where I averaged 23mph): https://www.strava.com/activities/866721999
...which was 22.3mph, though to be fair with a lower relative effort score. I don't think I could quite hit that if it was a real course, and if I was flat out I might be able to get that closer to 23 on Zwift... but I'm pretty confident that in real life I could get that into the mid-21s.
As far as the impact on mileage, If you're riding an average of 23 instead of 21.5, then you're covering an extra 1.5 miles every hour, or about 7% more distance. I've had a 3,000 mile target for the past several years, so that comes out to 210 miles against my annual target, or of the ~2,200 miles I've logged since I joined Zwift, that's probably overstated by about 150 miles, across... three years? Four years?
It's not immaterial, and just because I held 23mph in a Zwift event for 30 minutes doesn't make me think I'm a 23mph cyclist... But I do think a large part of the impact is that you never need to slow down or stop, so your average isn't getting pulled down as you're decelerating nor are you burning proverbial matches as you get back up to speed after stopping. It's close enough that I don't really lose any sleep over it.