Standing up near impossible on MTB

I’m using a MTB together with my Swift Hub. Thanks to @Roberto_Viola and his great QZ app I am finally able to enjoy Zwift as it is meant to be, which otherwise seems pretty much impossible with a standard modern MTB gearing. This has already been discussed in /t/new-to-zwift-hub-trouble-with-mtb-setup-and-resistance/595553/64.

Now there’s another issue however:
Whenever I am asked to stand up during a workout session in ERG Mode, it seems that I can’t deliver the (low) power and/or keep up with the cadence asked for. As soon as I get up everything feels much too easy with my setup. As I feel hardly any resistance in the pedals, I have more or less sustain my body position on the bars with my arms and upper body and try to “air pedal” to keep the cadence high enough.

This feels very unnatural and can’t be how it’s meant to be, does it?
I mean, in real life, I stand up when I really want to throw all force and body weight into the pedals on the steep climbing sections. It’s not really meant to be a workout for the upper body?

Unfortunately I don’t understand Zwifts ERG Mode well enough to know if that could also be related with the gearing of MTBs compared to road bikes? Does anybody experience something similar with a MTB on a Zwift Hub?

Hi @DirtyHarry just to continue my discussion here, i guess we can add into QZ a way to use a temporary gear value when the cadence value is lower than a value predefined from you.

In this way you should be able to bypass this issue.

I’m very curious about the community feedback about this idea!

Happy ride!

I don’t understand your question. When you’re in ERG mode, the trainer provides a set resistance to maintain the power required, so your gearing should be (almost) completely irrelevant. The resistance in ERG mode also should not alter just because you are standing.

Are you saying if you have, say, a 500W interval in Zwift and you use ERG mode, that you feel “hardly any resistance”? Because I don’t think that’s anything to do with your gearing or MTB usage if so, that sounds like either you are getting wheel slip (if using a wheel-on trainer) or your smart trainer is not applying ERG mode properly (if using a wheel-off trainer).

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It is an issue with Zwift for sure.

You just need a setup that has a lot of extra resistance available.

If using ERG workouts, design a workout that has higher resistance for the stand up intervals.

Most the workouts on Zwift were designed for road riders on road bikes riding in the seated position.
That’s not how we mountain bike.
Zwift still doesn’t have MTB specific routes or workouts.
Yes, there are VO2 max and anaerobic workouts and these are better suited to MTB but for the most part, they don’t really fit the MTB experience.

I like to use 40/20 intervals and do the first 10 out of saddle and the last 10 seated.
The difference in the gearing is huge.
I find I have to pedal easy (kind of, still hard) to avoid overshooting the power goal.
I will modify the workout as I get stronger.
I pretty much ignore the cadence goal but do generally to to spin faster or slower according to the recommendation.

You’re absolutely right @D.A !

That’s why I am so confused as well.

I am using a Zwift Hub as my trainer. I mounted my MTB on it and, as was discussed here before, the gearing on a MTB does not work great with Zwift in general. @Roberto_Viola s QZ solves this, by adding some sort of ‘base resistance’, so that MTB riders can feel enough resistance on flat surfaces as well.

In ERG Mode that shouldn’t be an issue at all, since the Power should always be determined by trainer. And it works great, even without the added ressitance by the QZ app.

I have troubles with the standing up sections though. Even though the power delivery asked for is close to or above my FTP of around 230 Watts, my 80 kg of body weight seem to pose no real challenge for the Zwift Hub and it’s just like I am stepping “into no resistance at all”. I feel like I have to balance my weight with my arms on the handlebars and “air pedal” to get even close to the cadence of 60 or 65 that I am asked to deliver. This does not feel right at all.

Not understanding the mechanics of Zwift well enough I am not sure if it’s my MTB setup or high body weight that leads to this. It certainly is NOT my “enormous” muscle power, lol. It seems like, even though the actual gearing on my bike should be irrelevant in ERG Mode, I get better experiences when I switch to the hardest gears when in ERG mode. That’s why I think the issue might be related to my MTB gearing and Zwift / the Zwift Hub not being really tailored to MTB riders.

ERG Mode works really great, except for those pesky standing up sessions.
@Roberto_Viola said he could add some extra resistance during these sections (and there’s no doubt that he could), but I am hesitant to ask him for it before understanding the underlying mechanics better.

I feel the same, especially regarding to “comfy” cadence goals that seem incredibly fast for what I am used to with my MTB.

@Roberto_Viola s app works wonders when doing normal rides though!

Hi @DirtyHarry

Some trainers need a range of “wheel” speed to be able to generate the correct amount of resistance. Have you tried Big front and small back to see if you can get more “wheel” speed.

A trainer is just a set of magnets next to a non magnetic drum, and resistance is generated by Eddy current, the speed of the drum create resistance.

Zwift doesn’t know that you’re standing. Your avatar will sometimes stand, but that’s all based on wattage and cadence. You can make your avatar stand while you’re seated. So any changes that might be happening in resistance are happening because of the wattages and cadences you’re putting out–that’s related to your standing/sitting of course. But not directly–Zwift isn’t detecting that you’re standing and then changing something.

It’s standard to shift up to harder gears when you stand–your body weight is coming down on the pedals more directly, so you’re putting more power through them. Most people also find that it’s hard to keep their cadence static when they stand if they don’t shift–effectively it feels like you’ve downshifted, because your weight is behind each pedal stroke making it ‘easier’. If you shift up (harder gear), you can find the same cadence and similar feeling of resistance as when you were seated. That’s all normal bike sort of physics, right? Indoor or outdoor, road or MTB :slight_smile: (Not ever sure how much experience anyone has riding, apologies if this sounds ‘basic’ to you)

So if you’re on a MTB and already at the higher end of your gearing hypothetically, and then you stand–if you can’t shift up to a hard enough gear from where you are (if you’re out of gears), you’ll start to spin out.

I know a lot of people who will compensate by taking some portion of their weight onto their arms/shoulders and the bars, that’s somewhat normal too. But could it be that you’re just at the top of your gear range already before you go to stand?

I think your bike physics is spot on.
In Zwift, we get an advantage.
When standing,we get the benefits of more power per cadence stroke but we don’t pay an aerodynamic penalty.

I’m not sure how they would alter the algorithm to catch this.

It’s like God smiles on mountain bikers and we get extra watts.

Hi @Gerrie_Delport_ODZ

Thanks a lot for your answer. That’s actually exactly the kind of information that I am / was looking for: I only have one (comparably small) front sprocket on my MTB and I was wondering if that was (again) the reason for Zwift not working as it is intended to be. I can’t even increase the size of the sprocket since my frame does not allow fitting a larger one.

Thanks @Tom_J

I am well aware of most of the stuff you mentioned in your post. It’s just that I think my issue might be related to my specific setup with a MTB and the respective MTB suited gearing. I have no experience at all with road bikes (I might have to change that…) but it seems MTBs are generally much more tailored to steep climbing sections and therefore much shorter geared?

The issue I am having is that as soon as I am standing up, I sometimes can’t even keep up with the power that is asked in ERG mode because the Zwift Hub simply does not increase the resistance enough. I lost one segment of my workout session today because of this exact issue.

When I remain seated, I can pull the power numbers no problem and ERG mode is compensating the resistance exactly as expected. But when I stand up, not only can’t I get the cadence figures high enough because I feel like spinning out already, I also have a hard time reaching the power figures asked because Zwift simply doesn’t seem to increase the resistance high enough.

I added another short ride after my workout today in normal (i.e. NOT ERG mode) and on a steep climb in a higher gear I was able to pull of the exact power figures that had been asked in ERG mode before with no problem. So technically it is definitely possible, it’s just that ERG mode doesn’t seem to work for me / my setup in this situation?

Also, standing up on a steep climb in normal mode felt like it should feel, with a lot of resistance that I could throw my hole body weight against, like it feels when I climb a steep section in the real world with my bike.

I guess it has to do something with the torque that one can deliver with e MTB gearing or the kind of torque / wheel speed one can generate with a MTB compared to a road bike that leads to this? Can this be the reason for this behaviour?

LOL, it’s more like the Zwift Gods despise the MTB folk, allowing road bikes to easily keep up with them for kilometers while having to output 1 W/kg less or so.
I mean of course road bikes are much, much more efficient on tarmac straights, but with the other Zwifters I “imaginary race” it’s sometimes borderline ridiculous. :smiley: It’s like if I was pulling a sack of potatoes behind me. :smiley:

Definitely MTBs are geared more for climbing than road bikes. You can find some 90s era MTBs that have large chain rings that approach road bike sizes, but modern MTBs are often 1x up front, and small rings at that. And it’s common to find dinner-plate cassette cogs in the back :slight_smile: Most MTBing doesn’t feature long sustained climbs, and when it does, it’s at lower speeds because of the terrain, so yeah, the gearing on them is very different, skewed heavily towards climbing. And, as you’ve found out, often the frames are purpose-built and limit the size of front ring you can throw on. I’ve got a gravel bike, not even a MTB, that is limited to a 40t ring if you run it 1x.

One question–when you say you can’t put a larger ring on the front. Are you running a 1x–a single chain ring? Or do you have a double, or triple? Often you can get a larger ring on if you go from a 1x to a 2x, or a 2x to a 3x. That’s because usually the limiting factor is the chain stays (a larger cog will hit your chain stay), and moving 1x to 2x or 2x to 3x adds a larger ring farther out away from the chain stays, so you can go bigger.

So depending on what you have, you might be able to swap out the crankset and get a bigger ring up front that way.

It could also just be this issue too. Different trainers respond faster or slower, and with more accuracy and range, in ERG mode. I don’t know enough about the Hub’s ERG mode quality, but if you’re geared really low, I guess it’s possible you could be maxing out the Hub’s ability to adjust via ERG. I don’t know as much about ERG mode than a lot of other people though.

I don’t use ERG, I have a dumb trainer and a power meter.
I have seen other ERG posters state that if they spin up too fast at the beginning of a harder interval, their trainer has difficulty increasing the resistance.
You might want to pedal a slower cadence before you stand up.

Hi @Tom_J

You are right, that could be a solution, I hadn’t thought of that. However, since I am currently running a 1x12 setup (dinner plates!! :slight_smile: ), that would mean that I’d have to pretty much overhaul my complete system including wiring and buying a shifter for the front sprockets… that really seems too much of a hassle currently.

That seems like a good idea, I will definitely give this a try! Thank’s for the idea!

For sure :slight_smile: If you or a friend happened to have a bunch of stuff in a parts bin, that’s one thing. (I may or may not have several cranksets at any given time that ‘still might be useful to someone!’ :smiley:) But buying a new chainring set/crankset, shifter and chain, and recabling–definitely a commitment. It can be done on the cheap if you don’t need high end parts, but it’s still some work. Good luck :slight_smile:

OK @Tim_Camden_C, I got a chance to try this today, unfortunately it did not improve my experience. I remained seated while slowly lowering the cadence, upping the power to the expected resistance level. Still, as I stood up, everything remained just super light and it was more or less impossible to keep up the with the cadence asked. Even shifting to the highest gear to get closer to a road biker kind of gearing did not improve the situation (which, kind of, is exactly how ERG Mode should work, but I tried anyway).

I feel OK at a cadence of around 55 to maybe 60, anything more and it’s getting weird.

Yeah, you are right, but it would also mean that I’d have to change the setup of my main and only real bike in a way that I never wanted it to be. With cheap parts and a biannual switching back and forth for winter season this could be feasible, but sooner or later I’d be getting into very cheap road bike (trainer only) territory as well? :slight_smile:

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Too bad.
Just as a possibility, right now, after the last update, ERG and trainer resistance is all messed up in many ways.
Maybe it will improve in the next week to weeks.

I read through the whole thread and I don’t think you mentioned what wattage your workout was actually asking for. Have you linked the workout you are seeing this with anywhere?

Some workouts have oddities in that they have very low wattages set while they instruct you to stand up. In those instances, if you try and follow the instructions you are going to be doing as you described - ‘air spinning’, as with the addition of gravity helping you and the extra leverage you have while standing, if the workout interval hasn’t been set to a multiple of your FTP it’s just not going to feel hard enough. This happens on all bikes (I have a road bike), not just MTBs. If I get a workout like this I just do my best to either achieve the cadence asked for, or the wattage asked for while sitting down, depending on what I thought the goal of the interval was.

In summary - it sounds like what you are describing is a workout interval that’s been set with a low wattage target and not necessarily anything to do with you riding an MTB. If you can link the workout you are doing or describe the wattage target that would help.

Hi @Kat !

Thanks a lot for you reply! Unfortunately, I do not remember the first occurence I was referring to above well enough, but I’d say it was at least something close to or slightly above the 200 W range? If it’s like you say it could really be a more general problem of Zwift asking riders of all sorts of bikes to stand up at power requirements that are simply too low.
What I can say is that if I’m not in ERG Mode I reach power figures of around 320+ W when I start standing up on a straight in a high gear.

However, I wonder how this could not have been adressed already, since it would be a pretty obvious problem and, given you enter your correct weight in Zwift, it should be manageable to estimate the minimal power to ask for each individual rider that would be required for standing up to make any sense?

In the meantime, I have pretty much settled to just remain seated and try to at least hit the cadence that is asked during those standing up sections. To be honest, I actuall kind of prefer harder efforts at lower candences, since everything from a cadence of 90 or 95 upwards feels rather weird for me. I’d say that I’d never reach such high cadences in real life. But maybe I’m doing something wrong?

Yeah - 200W standing seems way too low for most riders for standing with any real resistance in the pedals. Some workouts are just not as high quality as others.

There are so many workouts available that if you find one that’s a bit rubbish I would just move on and not do it again. What’s On Zwift is a great resource for workouts if you are not already aware of it.