Power Meter Pedals on Spin Bike

I know this gets asked a lot but very few people seem to have my spin bike so finding answers has been tricky.
I’ve been doing a lot of research and I am looking at getting Favero Assimo Uno power meter pedals for my Sole SB900 spin bike to make it more useful for Zwift. I know it’s not the gold option but it’s what I’ve got and was what I bought before realising the downsides for Zwift. It only currently estimates wattage based on speed which is pretty useless for Zwift.
I know I will have to adjust resistance manually but at least the wattage would be accurate.

However, before doing so I’d like to just check that they are compatible because I’m not a cyclist and have had a steep learning curve the last week learning new terms and about clipping in etc. All this is new so bare with me.

The manufacturer said “as long as they’re the same thread size it would be okay to do” but I don’t know for definite what thread size they are and it’s not in the manual.

To cut a long thread short, I’ve taken some photos of the existing pedal and thread and hope you can confirm that it is the standard 9/16th’s and that it doesn’t matter if fitting with a spanner or hex bolt.

Crank arm length is 200mm long so seems to be longer than standard bike cranks.
The provided spanner is 15mm
The end of the pedal shaft has 20.11 written on it but wasn’t sure if that was the thread tpi or for something else.

Thanks very much

Crank length is measured from the middle of the bottom bracket to the middle of the pedal axle–basically, between the middles of both holes in the crank arm :slight_smile: So you’re probably looking at 175 or so, just eyeballing off that pic.

Those certainly look like normal pedal threads. Trying to judge tpi off that pic is hard, lol. But standard pedals are 20tpi. (don’t know what the 20.11 stamp is, could be tpi, which will be close enough.) And honestly, ime non-standard pedals are pretty clearly non-standard. That spin bike company would have had to have special pedals made for them that were suuuuuper close to standard in order for those to not be standard. And why would they do that? :slight_smile:

Oh, and what tool is used to install won’t matter, spanner or hex.

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The two popular pedal threadings are 9/16"x20TPI, and 1/2"x20TPI. In my experience the latter is only found on one-piece steel cranks which you don’t have. I would be quite surprised if you did not have standard 9/16"x20TPI pedals because it would make no sense for Sole to manufacture a proprietary pedal or use 1/2". You could also take a pedal to a bike shop and ask them what it is.

Keep in mind that pedal threads are right-hand thread on the right side and left hand thread on the left side.

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It could be a 35 year old French spin bike, you never know. :wink:

Thank you very much Tom and Paul.
Thank you also Tom for the crank length measurement correction. Good to know it’s standard length!

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I have fitted Wahoo power pedals on a Sole SB700 so I bet you be fine :slight_smile: Remember to add some grease when screwing in the pedals.

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Ah, finally found a fellow Sole bike owner! Thanks for letting me know. Can I ask - do you find it does actually make a real difference using them with Zwift? eg when climbing hills, if you increase the resistance you do actually get the benefit from the pedals?

It is my friend who has the SB700 where I had a pair of power pedals leftover so we could ride together on Zwift. It’s worth noticing it is an older SB700 which doesn’t calculate wattage at all so I am unsure what you are experiencing when going up hill when the bike is calculating the wattage.

I have done a few rides on it. The fact that is it is quiet and very smooth makes it an enjoyable experience. When you add resistance your watts also increases but depends on your riding style. If I understand the wattage calculation of your bike correctly it is only calculated on how fast the wheel is moving? With the power pedals you can have a cadence of like 50rpm and then output 400 watts if you set the resistance very high.

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Thanks vey much Mikkel. Mine is the new version so yes, it does guestimate wattage but I checked with the manufacturers and yes, it only bases wattage on RPM so pretty inaccurate and definitely useless for Zwift when everything is based on watts.
With RPM there’s only so fast I can pedal!

At the moment it shows watts but if I’m going up a 4-5% hill in Zwift I basically just slow down to a crawl with everyone around passing me like it’s nothing. Quite frustrating.

That sounds like what I wanted then. Not sure I’ll manage 400 watts yet but it would be nice to actually have an ability to set the resistance higher on a hill and have it output more watts and I assume that would make it more realistic in Zwift?

Otherwise it is a nice bike and very smooth and quiet like you say.

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You will definitely have an easier time following the group up hills with the pedals :slightly_smiling_face:

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Thanks Mikkel, that confirms what I hoped so that’s great.

I have a follow up question - I got my pedals yesterday and have installed them today. On first test they are working well and it looks like the watts guestimation from the sole spin bike was about 40% higher than reality at the same cadence.

What I wanted to check was in Zwift, I connected the pedals via the power meter option. I also connected them via the cadence connection. Is this correct or should I only connect via the power meter?

Can I also confirm that you keep the “double the power option” for Uno’s OFF?


Bluetooth connection allows for multiple connections at once. I pair both power and cadence to Zwift using Bluetooth. I think that Ant+ can only connect to one thing at a time. I use Assioma Unos, too, from time to time.

Favero Assioma introduced the Bluetooth option to double the power because a few people were experiencing data transmission problems. With some setups, I was told that a bit of data gets lost in transmission. Computers communicate numbers as a sequence of bits. Each bit added to a number increases its value by exactly two; therefore, if a bit is lost, you will get half the number you should be getting. This happened to me. It was a little odd that I could squat with a 90 kg barbell for thirty reps in a minute and my one-minute power was supposedly only a little over 400 watts at the time! But I shrugged it off as short legs. I wasn’t aware anything was wrong until I got tested at a medical rehab facility on a Monark Cycle. I’m not sure how accurate your spin bike is, but I assume that you had double power “ON” and you still got a reading from your Assioma Uno that was considerably lower than what your spin bike gave you. Maybe you could do what I did.

Still, that being said, for most, the correct option is to select “OFF” for double power.

Thanks Rob. I am connecting the Assimo’s directly to Zwift via my iPad and was able to connect both the power and cadence so I guess that must be using Bluetooth then?
I have the double power “OFF”.

I will start by saying I’m not very fit and the reason I got the bike was to improve fitness and leg strength so I don’t expect to have high wattage. I’m also fairly small and light. I can’t currently manage to use the bike on higher resistance. It’s probably at about 1/4 of the maximum but if I increase the resistance the wattage jumps up.
Today I was getting 60 watts at 55rpm ish with lowish resistance. I have no idea what my wattage would be as I have no previous reference point and I don’t have a normal bike.
However, the spin bike monitor was saying about 80 watts for the same RPM and I have no confidence that it is accurate in any way as it only measures based on speed. There is no resistance value on the bike monitor.

Given it is not half the wattage of the bike I would think that it’s probably correct?

I looked and it seems that you can pair multiple devices to one ANT+ sensor; however, if your Assioma App gave you the choice to double your power then it must be a Bluetooth sensor that you’re using.

To get some idea of how much power you can use you could try what Zwift calls the “Sniff Test”. Check this topic (Are your power numbers accurate? Take a quick test. | Zwift Insider):

You’re fairly light, so it’s more likely that your setup is correct, but I can’t say for sure.

No, the opposite is more true. Traditionally, Bluetooth devices could only connect to a single other device at a time. Now the BT protocol has moved on to support one-to-many connections, and a few trainers and other fitness devices support this (though most don’t).

ANT+ works in a very different way and is a broadcast technology, such that a device sending ANT+ data can be picked up by multiple receiving devices (e.g. a Garmin and a device running the Zwift game app).

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