MTB with Cog - Performance

General Discussion
1

Hi.

Sorry if this has been asked before but I can’t find anything that answers this specific question. The answer doesn’t really matter either way but I’m curious anyway.

Currently have a Kickr Core with Click and Cog, so virtual shifting. I have a MTB attached and works pretty well. In theory, does this mean the possible raw watts or w/kg output could be same as using a road bike? At the end of the day it’s now just a frame with a chain on it… So in my pea brain I’m assuming it should be similar to a road bike. I guess the geometry would be different but it wouldn’t make that much of a difference would it (at least at a beginner level)? I guess I’m curious as to whether this setup puts me at a significant disadvantage in races.

Lastly a quick bit of background, which isn’t really relevant but I’m anticipating some questions and other comments. I’m a complete beginner to Zwift, and cycling for that matter. I wanted to supplement a lot of other weights exercise I do and I’ve fallen a bit out of love with running. So I bought a Kickr Core with Cog as a bit of a Christmas present to myself. I have an MTB which has been stuck in the shed for years unused so that’s what I’m using. I don’t really have any interest in riding outside, nor do I ever anticipate reaching, or really want to reach, a high race score. Furthermore I can’t see me wanting to ride mammoth distances, I’ll be sticking to 50km and less (more of a time thing than anything). Anyway, I’m just curious how a MTB in this scenario would perform against a more suitable road bike frame.

2

I would like to know as well. I am on a full sus with a giant trance. With the rebound as slow as possible, i don’t bounce much, especially seated, but we definitely lose some watts standing. I can’t fully lock my shock and my fork definitely doesn’t lockout. But i am using it for training and not doing any zwift races so I figured it doesn’t matter.

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4

Virtual shifting is a great help for MTBs, since without that you would probably find the physical gearing too low for racing.

5

Yes absolutely. That’s the answer I’ve found in most other places when users are specifically talking about this.
So I’m wondering if there are any other limiting factors that aren’t ‘fixed’ by using the cog. Really a few watts here and there is kind of a given but I’m curious if I’m sacrificing, lets say, 50 or 100 watts avg or a few points on W/KG.

6

The only loss would be pedal bob from suspension. Set the LSC to max firm or flip the climb switch. You could zwift on your mother-in-law’s board walk cruiser if you wanted. The only disadvantage might be rider position being less than anatomically ideal for putting max power through the pedals.
If using the zwift cog your actual gears on the bike wont matter as its “virtual shifting” doesnt have to match what you actually have.

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