Fluid Trainer Resistance

blacksm

Hi, I'm using a Elite TurboMuin Smart B+ trainer. I notice however that the fluid resistance seems really high. It's been like that since the day I bought it. I can barely ride anything past 39x17 for a long duration as the resistance is too high. I have never been able to use my 52 chain ring on this trainer. This trainer has no controllable resistance. Also I realize when I'm coasting it can only freewheel for a few seconds before the resistance stops the flywheel. Whereas I've noticed in some videos online, people using other trainers can coast for pretty long and the flywheel keeps spinning. Because of this I'm unable to coast too long on rides which can get a bit uncomfortable on longer rides as I virtually have to pedal non stop to prevent getting dropped from the group. Is this normal for this trainer and how is the effect on those trainers that allow you to coast longer. Does the speed drop much? Or can you still coast and stay in the group because the flywheel is still moving?

Secondly I just want to roughly make sure that my power output is right. At 39x19 around 70rpm I'm putting out around 130W or so on Zwift? I'm 62kg btw. Does this sound right?

Thanks for the help!

diamonddog

I have had wheel on and now direct drive and once calibrated none will freewheel for long it just spins down, that is the idea of turbo training you don’t get to have a rest. As to the gear you can use make sure that your turbo is calibrated to the app you use.

blacksm

Oh ok. Was just wondering as so many nowadays seem to free-wheel quite a bit. That's why I was asking.

diamonddog

I don’t know of any turbo trainers that will freewheel it goes against the whole idea of a ‘turbo trainer’, if you stop pedalling they should spin down to a stop within a few seconds.

larkim

That gearing vs wattage does sound high if it's meant to be equivalent to a real life ride. 39x19 on 23mm tyres at 70rpm is just under 12mph road speed. 130w for a lightweight rider (well, compared to me!) at 12mph sounds high, and defeats the point of being able to ride "normally" if the fluid is resisting way more than a real life ride would, surely? Wouldn't the expected w be 50-60w for that sort of speed on a flat, smooth road without wind?

pblakeney

The Tacx Neo freewheels on a descent if plugged in. Maybe that's what he/she has seen?

diamonddog

Yea, maybe that is what they have seen.

blacksm

Thanks for the replies guys. Blake and diamond, the free wheeling I'm talking about isn't the downhill drive that the TacX Neo has. But simply just turning the pedals a couple of revolutions and stopping as I've seen in some of the unboxing videos or reviews keeps the free wheel spinning and I guess it would allow you to coast a bit in game? I'm not sure how that translates to what happens in game but I would really like to know. Even the Wahoo Kickr free wheels quite a bit.

Yeah larkim I feel that I'm having to put more effort than I should for the resultant speed due to the level of resistance that the trainer is providing.

I really would like to know how much difference there is compared to some of the newer trainers out there as this one is at least 5 years old if not more.

diamonddog

None as most of the latest trainers will react the same if you stop pedalling.
My latest trainer is one of the new Tacx direct drive ones at 6months old and as with most trainers as soon as you stop pedalling it will start to spin down therefore you start to slow and power drops so you have to then put more effort in to get back up to previous power and speed.
A longer spin down time or freewheel time to me says that the calibration has not been set correctly.

diamonddog

Just for a bit of clarity, I have on my turbo bike 52/39 and 12/25 cassette and 70rpm gives me way below 130 watts so check your calibration.

pblakeney

A heavier flywheel will give a longer freewheel time.

blacksm

Hmm. That's odd. This is the link for a TacX Neo https://youtu.be/9DqiBksaVSY
At 6.25 we can see how long it free wheels.

This is one for the Kickr Core.
https://youtu.be/R8Di25Rs4pg
At 6.12.

Also I don't know if it's something wrong with my belt tension or not as like I mentioned there is no way that I can spin away on my 52 chain ring like a lot of them are doing in these videos. I literally sprint on 39x17 or so because that's how much resistance I'm getting from the trainer.

Blakeney, I guess this would make sense. Although I think the Turbomuin has a pretty decent flywheel weight? 6 or 7kgs I think.

pblakeney

The two videos above are plugged in power units.
I can confirm that the Neo does act like this, when your session is over. It does not do this during a "ride" on the flat.
6 or 7kgs sounds adequate. Any chance you are overthinking this? As long as you get a workout the rest really doesn't matter.

blacksm

Oh ok. I have no idea really as I have nothing to compare it to? As in physically try it out and feel the difference. I guess I'm just trying to see if there's something I can do to coast just a slight bit longer during rides which will allow for a few more seconds of standing time and therefore make it more comfortable on longer rides? And also trying to find out if my power numbers are correct?

pblakeney

I would just change down a gear or two for recovery. 😉
Perspective - My FTP is in the mid 200s depending on turbo. My wife struggles to put out 100W.
As long you as you see yourself improving then the numbers themselves mean nothing.

webboo

I have an Elite turbomuin. I don’t have any of the tech stuff you can use with it. However it has the most resistance of any turbo I have used over the last twenty plus years. I don’t think even if I had screwed the roller till it was touching the rim on my wheel on my old fan fly turbo, there wouldn’t have been as much resistance.
I tend to do shortish duration intervals such as 15 secs on 15 secs off. I will in 53x25 or if I’m feeling strong 39x17. I can use bigger gears but only if I drop the revs below 90.
I was hoping that I would never have use a turbo trainer again when I retired but alas British weather and injuries means you can never escape.

larkim

I guess once upon a time it didn't really matter if one turbo was harder to drive than another as you weren't measuring the miles, you were just measuring the time taken and the overall work rate, even if it was only spinning a virtual rear wheel at 10mph despite you putting in 180w of effort.

Now it does matter - there's no point in your turbo reporting you doing 10mph at your max output if the same effort on someone else's turbo would see you doing 25mph in a virtual race on Zwift etc.

pblakeney

Nicely sums up Zwift. Thanks!
There are reasons that some can maintain 10W/kg and it is not fitness.

bobmcstuff

larkim said:

I guess once upon a time it didn't really matter if one turbo was harder to drive than another as you weren't measuring the miles, you were just measuring the time taken and the overall work rate, even if it was only spinning a virtual rear wheel at 10mph despite you putting in 180w of effort.

Now it does matter - there's no point in your turbo reporting you doing 10mph at your max output if the same effort on someone else's turbo would see you doing 25mph in a virtual race on Zwift etc.

I mean, Zwift converts your power output in watts to your speed, your rear wheel speed or any other speed reported by your turbo has absolutely nothing to do with it.

All else being equal (height, weight, in-game kit etc.) a rider putting out 180W will move the same speed in Zwift as any other rider putting out 180W regardless of what the turbo may be saying about speed.

Now, as to whether all else actually is equal - totally different question! Lots of people cheating by:
- entering incorrect weight (very common, I suspect a majority of riders at the least "round down" to nearest kg, and there does seem to be an abundance of 45kg riders about putting out 300+ watts...)
- entering lower height (fairly common - reduces drag in-game for same power on flat road),
- deliberately miscalibrating their trainer (possibly less common as it requires some technical know-how, but clearly does happen)
- Buying a trainer which is known to over-report (e.g., some are known to over-report sprint power by a few % - potentially that's quite a few watts in a sprint - this is probably less common )
- Using a motor (why??)
- Other technical hacks of Zwift which I don't know about

pblakeney

In theory all will be equal in Zwift. All turbos are not equal.
My KK RnR gave me an FTP of 295W.
My Neo 2T gives me an FTP of 235W.
I am therefore slower in Zwift on the Neo.
A comparison test between a real route and the same in virtuality on the Neo proved the Neo to be accurate. Burst my ego but that is the reality and I prefer that to being fake.

bobmcstuff

That's a problem with the power meter/measurement in the turbo - one of them (or possibly both) was not calibrated correctly. The Neo is supposed to be very accurate though (https://www.dcrainmaker.com/2018/12/tacx-neo-2-smart-trainer-in-depth-review.html), so presumably it was the RnR. Especially if an older non-smart RnR using virtual power, there are loads of potential sources of error if you use virtual power.

Still, your rear wheel speed on the turbo has no effect on anything.

pblakeney

100% it was the virtual power thing. Would come in handy on Zwift if I wanted it to.
It's why I say the figures themselves are meaningless as long as they are improving and why I take Zwift with a pot of salt.

blacksm

Hi Webboo. Exactly what I mean! The resistance on this thing is pretty hardcore! I mean I guess on the bright side it's good training but on the other I would like to know how much power I'm actually putting out and how much difference this specific trainer is compared to let's say a Neo 2t in terms of figures and ride feel.

Of course I couldn't be bothered with all that cheating stuff and I know people do it. It's bound to happen in almost any 'game' but I just ride to improve myself and I really don't care if they go shooting off. I just want to be able to gauge my actual capability when I'm on it.

As I don't have a power meter on my bike itself, I can only gauge it when I'm on the trainer. I've never really bothered about training with power before this as I hardly used my trainer since we could ride outside, but after using it so much now I see how important power readings can be and how informative too.

Btw Webboo, do you have any of the newer trainers available now? And how would you compare it to the turbomuin?

webboo

I haven’t tried any of the new trainers, so I can’t help you with comparison. I only got the turbomuin because it was pretty quiet and on offer. I needed to have turbo trainer in the hour as I had just had a shoulder operation.

diamonddog

OP, I have just done a session on the turbo and using 39/17 @ 70 rpm gave me approx 117/118 watts, in the 124/125 watt range cadence was around 86 rpm, all these figures were via the app I use. The trainer is a Tacx Flux.

EDIT: The wattage at 70 rpm is 93 watts using 39/19.

bobmcstuff

blacksm said:

Hi Webboo. Exactly what I mean! The resistance on this thing is pretty hardcore! I mean I guess on the bright side it's good training but on the other I would like to know how much power I'm actually putting out and how much difference this specific trainer is compared to let's say a Neo 2t in terms of figures and ride feel.

Of course I couldn't be bothered with all that cheating stuff and I know people do it. It's bound to happen in almost any 'game' but I just ride to improve myself and I really don't care if they go shooting off. I just want to be able to gauge my actual capability when I'm on it.

As I don't have a power meter on my bike itself, I can only gauge it when I'm on the trainer. I've never really bothered about training with power before this as I hardly used my trainer since we could ride outside, but after using it so much now I see how important power readings can be and how informative too.

Btw Webboo, do you have any of the newer trainers available now? And how would you compare it to the turbomuin?

Yeah so that's where you need a turbo with accurate power measurement, or a powermeter on your bike, if you want to know for sure how much power you are doing.

I previously used a Tacx BlueMotion (cheap dumb trainer from about 2014) with virtual power on TrainerRoad. I'm now using a Kickr Core bought last year, which has its own power measurement. I can say that in general, virtualpower with the BlueMotion was pretty close to what I am now getting off the Kickr, my FTP results are basically as expected. It was more or less fine for training - consistency is more important then.

The thing that was an issue with the BlueMotion was variability - like if you changed tyre pressures, or it was much hotter or colder one day, or if you wound the roller a bit tighter or looser when putting the bike on, the numbers would go completely to pot.

Although I see from Google that your particular trainer does measure power, so that shouldn't be an issue for you specifically.

I can see from further Googling that it apparently has widespread power issues, so maybe that is it... Some reasonably recent stuff here: https://www.trainerroad.com/forum/t/how-close-does-the-virtual-power-tr-of-an-elite-turbo-muin-smart-b-correlate-with-real-power/5778/2

blacksm

Thanks for the numbers Diamond. Thanks for the info and link too Bob. Yeah I guess the only way to know for sure would be with a separate power meter. I always felt like it was under reading though. I guess the amount of resistance that it has makes you think that you're putting out more power than it displays, not sure. I guess the other way to find out would be to jump on someone elses trainer and see.

larkim

bobmcstuff said:

larkim said:

I guess once upon a time it didn't really matter if one turbo was harder to drive than another as you weren't measuring the miles, you were just measuring the time taken and the overall work rate, even if it was only spinning a virtual rear wheel at 10mph despite you putting in 180w of effort.

Now it does matter - there's no point in your turbo reporting you doing 10mph at your max output if the same effort on someone else's turbo would see you doing 25mph in a virtual race on Zwift etc.

I mean, Zwift converts your power output in watts to your speed, your rear wheel speed or any other speed reported by your turbo has absolutely nothing to do with it.

All else being equal (height, weight, in-game kit etc.) a rider putting out 180W will move the same speed in Zwift as any other rider putting out 180W regardless of what the turbo may be saying about speed.

Not always. If you have a dumb trainer (as I do - Elite Crono Fluid), and you don't have a power meter (like me - only speed and cadence) then the "only" thing that Zwift knows is your "speed", and it then backwards calculates what it thinks the level of power would be needed to create that "speed" on that trainer. And it then also corrects for the fact that pushing that particular trainer at that "speed" is plus or minus "real world" speed.