MyVeloFit - my thoughts….

[bikerboy337]

So I have been riding bikes for 20 years now, but never had a professional fit in my life. I’ve had my seat height the same for at least 10 years now, fit on my bikes has been pretty identical for as long as I can remember… little more stack on my gravel bike but otherwise stack, reach, seat height, etc all carry over pretty well. Also never had any use injuries from cycling…

Decided to try out Myvelofit and pay for a fit on a new bike I’m dialing in and to my surprise my seat height was lowered by about 15mm from what I’ve been riding for years… and it feels great….this was a huge surprise to me… all my other measurements/fit were about dialed in, recommended a slight longer (5mm) reach and bar height (5mm) on the bike I’m dialing in, but lowering my seat was a big surprise for me…

I’ve only got a few rides on the new fit so far, but so far it just feels better than my past position… less strain on arms and bottom…

Anyways, just wanted to put out some good thoughts on the service… for $35 to realize my saddle has been about 15mm too high all these years… and looking forward to really seeing how it impacts my feel longer term once I get a bunch more hours on the fit…

[Zackus]

I think you've convinced me to give it a shot. especially for $35.

[RoosterCogset]

Interesting premise. So for you, with the 15mm saddle drop and 5mm bar lift, netting out with a 20mm less saddle/bar drop? I'm curious how the software can determine measurements -- do you start by providing your current bike's geometry details, as well as your own physical measurements (eg. leg, torso, arm lengths etc)?

[bikerboy337]

Quick summary, I used my iPad to record short 60 second videos on the trainer… the software reviews angles for hip, knee, back etc and recommends a proper range for each based on how aggressive you want to be, flexibility, etc…and then recommends adjustments to seat height, saddle core/aft, handlebar height and reach… I saw very small adjustments to all except seat height… it wouldn’t give me fire/aft adjustments until my saddle height was in the recommended range…

I found that it’s best to warm up for 15 minutes then record a snippet, get nice and settled into my riding position. Hands on the hoods… they explain it all really well.

As someone with no previous riding issues I felt this was well worth it.. if I had nagging injuries a professional would definitely be the way to go, but from the reviews I read before I tried it, the fit worked out very similar to what professional fitters gave… again, no knee or back issues for me and a standard build for my body…

[RoosterCogset]

Originally Posted by bikerboy337

Quick summary, I used my iPad to record short 60 second videos on the trainer… the software reviews angles for hip, knee, back etc and recommends a proper range for each based on how aggressive you want to be, flexibility, etc…and then recommends adjustments to seat height, saddle core/aft, handlebar height and reach… I saw very small adjustments to all except seat height… it wouldn’t give me fire/aft adjustments until my saddle height was in the recommended range…

I found that it’s best to warm up for 15 minutes then record a snippet, get nice and settled into my riding position. Hands on the hoods… they explain it all really well.

As someone with no previous riding issues I felt this was well worth it.. if I had nagging injuries a professional would definitely be the way to go, but from the reviews I read before I tried it, the fit worked out very similar to what professional fitters gave… again, no knee or back issues for me and a standard build for my body…

Thanks, but I guess I'm wondering how the software determines any scale in the scene it's evaluating, unless you provide it some sort of measurements. Ie. how does it tell if it's looking at someone 5'3" or 6'4", on a 50cm vs 60cm bike, where the adjustment amounts might be different?

[lorenbike]

Originally Posted by RoosterCogset

Thanks, but I guess I'm wondering how the software determines any scale in the scene it's evaluating, unless you provide it some sort of measurements. Ie. how does it tell if it's looking at someone 5'3" or 6'4", on a 50cm vs 60cm bike, where the adjustment amounts might be different?

Do you need to calibrate the video, ie like a yardstick or measuring tape in the frame?

Cool concept for $35 that's tempting to test, but I don't have a bike trainer.

[RoosterCogset]

Originally Posted by lorenbike

Do you need to calibrate the video, ie like a yardstick or measuring tape in the frame?

Cool concept for $35 that's tempting to test, but I don't have a bike trainer.

maybe by assuming you're on 700c wheels?

[benb]

The crazy thing is with modern machine learning if you fed in enough data on a population of riders it will get it right without actually being aware of anything. You’d just have to give it videos and data on whether the video represents a good fit for that rider.

It would sure require a lot of data though! More than a little company selling $35 apps would be able to get! Bike fit has a lot of variables and one camera angle wouldn’t be enough for everyone.

[jklooner]

Thanks, but I guess I'm wondering how the software determines any scale in the scene it's evaluating, unless you provide it some sort of measurements. Ie. how does it tell if it's looking at someone 5'3" or 6'4", on a 50cm vs 60cm bike, where the adjustment amounts might be different?

Originally Posted by benb

The crazy thing is with modern machine learning if you fed in enough data on a population of riders it will get it right without actually being aware of anything. You’d just have to give it videos and data on whether the video represents a good fit for that rider.

It would sure require a lot of data though! More than a little company selling $35 apps would be able to get! Bike fit has a lot of variables and one camera angle wouldn’t be enough for everyone.

To provide a little context to these questions, the value-added of the app is the automatic body measurements. For this part, they are not training their own data, instead they use a toolkit provided to app developers (I believe it's directly from Apple) that is used for fitness apps to detect people's skeletons in video scenes. This toolkit uses ML models trained on tens of thousands of people at least. When you do the initial measurement, you give them your height and put QR codes on your calves and chest to assess proportionality. It then measures torso length, femur length, ankle location, forearm length, shoulder width etc...

From that point on my guess is that it is rule-based. Perhaps they use the measured parameters and feed it to a linear classifier that says this is a good fit and suggests changing certain things, which they certainly have enough examples for. Maybe it or Retul uses a more sophisticated reinforcement learning model or something, but the model needs to be able to explain how to change parameters to affect overall fit. But my guess is that it is rule-based, which is probably how most run-of-the-mill fitters probably work. Really experienced fitters are probably more like sophisticated ML classifiers that can eyeball the outcome, but can then work backwards.

-My 2c.

[fourflys]

so I did the pre-purchase sizing part of the app yesterday to see what they might suggest.. for best results you print out a couple symbols and tape on to your chest and one to your calf, start the app recording and, as prompted, turn around twice. Once it analyzes the video, it will confirm your height and overlay the "bones and joints" on your picture.. this was really accurate for me, the joints were right where they were supposed to be and the bones seemed to accurate.

The app lets you decide between three riding styles, relaxed, neutral, and aggressive, and lets you change that if you want later. It will then suggest bikes from it's database based on your proportions and selected riding style, often giving you two adjacent sizes to choose from. You can then click bikes you're interested in to compare and look at how you would sit on that bike.. one cool thing I figured out a bit later was the app will let you change some bike parameters like stem length or rise (it will default to what comes on the bike at a selected size). This is cool as if you are at the edges of the back or shoulder angle graph (stem rise and length respectively), you can adjust and see where that puts you.. for example you can effectively flip the stem if your back angle is too low for a given size..

I haven't done a fit yet on the app yet, but this is a good tool to see how certain bikes might fit you.. I have no idea if that initial video will play into a fit on a bike since it's in my profile..

while I'm sure MyVeloFit isn't the same as an in-person fit, it's more informative for me at this point as the two fits I've done on my Roubaix were just to try and make that bike fit, even thought I told both fitters to tell me if I needed a smaller bike, etc.. if I ever do another in-person fit, it will be with a fitter that has a size cycle..

[EB]

This kind of analysis has the potential to really change how fitting works. Though you can do it on your own, a fitter can still provide the equipment (eg trainer, bike components, etc) and guide the rider through the process while still relying on the technology for the measurements and suggestions.

One part I wonder about is adaptive fitting - a human fitter with physio experience is capable of adapting fit to health issues and biomechanical responses that aren’t going to visible to a camera or a machine learning model.

[fourflys]

Originally Posted by EB

This kind of analysis has the potential to really change how fitting works. Though you can do it on your own, a fitter can still provide the equipment (eg trainer, bike components, etc) and guide the rider through the process while still relying on the technology for the measurements and suggestions.

One part I wonder about is adaptive fitting - a human fitter with physio experience is capable of adapting fit to health issues and biomechanical responses that aren’t going to visible to a camera or a machine learning model.

for sure, the biggest liability of this process is the app can't know if you have any major flexibility issues, leg length issues, etc.. I think if you are honest about your riding style (relaxed, neutral, aggressive), you will probably get a good fit unless you have some of those issues mentioned prior. I think the issue will be someone like myself that doesn't ride 200 miles a week, has a bit of a belly, and isn't the most flexible choosing the aggressive fit because that's what I think I should be.. for the record, I chose relaxed as I feel I can always make a relaxed fit "neutral" by lowering the front end or extending the stem..

[mcteague]

For most folks considering getting a bike fit...just try lowering your saddle about 10mm at a time and try it out. Also, having a fit by an actual person, with real experience, can look for things computer programs don't. Such as dropping your heel when pedaling really hard. Saddle height can look fine when just spinning on the trainer but things tend to go to hell when you really grind.

Steve Hogg has some nice insights on this:
https://www.stevehoggbikefitting.com...ard-can-it-be/

Tim

[fourflys]

Originally Posted by mcteague

For most folks considering getting a bike fit...just try lowering your saddle about 10mm at a time and try it out. Also, having a fit by an actual person, with real experience, can look for things computer programs don't. Such as dropping your heel when pedaling really hard. Saddle height can look fine when just spinning on the trainer but things tend to go to hell when you really grind.

Steve Hogg has some nice insights on this:
https://www.stevehoggbikefitting.com...ard-can-it-be/

Tim

that's some good points.. the one niggle I found is the sizing part of the app wants to have my saddle height at 71cm (based on the body scan, as it didn't ask my inseam).. both of my in-person fits had me at ~68cm.. also I have my cleats pushed all way the back to get a more mid-foot position, I assume the app might be going from a more traditional "KOPS" method? That would certainly alter my seat height..

the value for me at this point is the sizing feature that gives me/reinforces for me a good starting point for what size bike to look at.. I have been on 54s or 56s (generally 380-390 reach numbers) for ever, based on common thought (I'm 5'8.5"-5'9")/what people have said is "my size) and they have always felt too long, even after putting shorter stems on.. the app has me on a 52cm (~370 reach) endurance bike and that sounds right to be honest. based on the above experiences.. I hope to get some good saddle time on a 52 prior to purchase though..

[m_sasso]

Originally Posted by fourflys

that's some good points.. the one niggle I found is the sizing part of the app wants to have my saddle height at 71cm (based on the body scan, as it didn't ask my inseam).. both of my in-person fits had me at ~68cm.. also I have my cleats pushed all way the back to get a more mid-foot position, I assume the app might be going from a more traditional "KOPS" method? That would certainly alter my seat height..

the value for me at this point is the sizing feature that gives me/reinforces for me a good starting point for what size bike to look at.. I have been on 54s or 56s (generally 380-390 reach numbers) for ever, based on common thought (I'm 5'8.5"-5'9")/what people have said is "my size) and they have always felt too long, even after putting shorter stems on.. the app has me on a 52cm (~370 reach) endurance bike and that sounds right to be honest. based on the above experiences.. I hope to get some good saddle time on a 52 prior to purchase though..

Going from a 56 to a 52 is a very big jump in bike sizing. You have obviously been riding bikes for some time, I guss the question raised in my mind, is it that you have just not paid attention to what you been riding durning this time? Fellow riders never mentioned you were on to big of a bike? Difficult for me to understand how you could have been riding all this time and not been so uncomfortable on a oversized bike. Lets hope this improves your enjoyment of cycling.