DIY Bike Fit Analysis


#1

I’ve had 2 professional fits done in the past - one back in 2013 when I first started cycling and then more recently in June 2018 (to address saddle pain on longer rides). The one in June 2018 ended up switching me to a new saddle and raising it up quite a bit compared to the 2013 fit.

I noticed some nagging knee pain later in 2018 while riding but I thought it was mostly from my running volume. Then I started to get some IT band pain towards the end of the year in addition to the knee pain even though I was taking a break from running after my 8K race in late November. To complicate things, in December I changed my group-set and ended up going from a 175mm crank arm to a 172.5mm. To compensate, I raised my saddle a couple mm and moved it forward slightly. That seemed to help a bit at first but I’m still having some IT band pain that is now showing up off the bike.

Since I don’t want to constantly rely on pro-fits ($$), I started researching this a bit on my own and I came across https://bikefitadvisor.com/ and this free online tool https://www.obstri.com/fit/ to measure angles from slow-motion video I captured on my iPhone. Based on the measurement of my knee at the top of the pedal stroke (71 deg), it seems that I may have raised my saddle a bit too much. I’m going to drop it down a bit closer to where it was originally from my 2013 fit since I never had any knee/hip pain between then and the fit in 2018.

I used some green sticky dots to mark locations on my hip, knee, and ankle based on some info from the bike fit adviser site and videos. The hip one fell off while I was pedaling but I did manage to get an angle marker on it in a prior frame.

If after a few months of trying to DIY it I still have pain then I’ll probably go back for another professional fit, but these free tools online are pretty cool so I thought I’d share.

Here’s what my setup looks like before I lowered my saddle. The family woke up so I ran out of time to grab new measurements after I lowered the saddle - so I’ll try to get to that later tonight once the kids are sleeping.

If anyone has any advice/suggestions, I’d love to hear it.


#2

Unfortunately, I am not a bike fit expert. Being so tall, the normal metrics don’t work for me and I have to go by feel at this point. However, I do have experience with knee pain. I use to have terrible knee pain on the front of the knee. I developed scar tissue on my knee cap and the tendon would rub across it causing a lot of pain.

It was not bike fit. It was all the steady riding at a moderate cadence. Steady riding puts a ton of pressure / stress on the tendons. When I changed how I rode the knee pain went away naturally after about 2 months. Not sure if that has anything to do with your case, but if you do long, steady rides it could play a role.


#3

Before 2018 my rides were sporadic and generally 30 minutes or less. The labs got me into the 60 to 120 minute range but with plenty of intervals so I’m not in the long and steady camp.


#4

I wish I could help, but really don’t have much to offer. I’m at 140, like you. I do know that a 1 or 2mm change in seat height for me makes a big difference - but the pain is either the front or back of the knee. Never the side. I don’t want to give you bad advice.

I do know that if your seat is too high you will feel pain in the back of the knee. If the seat is too low you will feel pain in the knee. @Coach_Theia has a guide on leg pain caused by bike fit. She is going to look it up.


#5

Thanks - I’m researching it a bunch on my end as well. I think it’s pretty cool that I can even look into doing this myself with only an iPhone and a tripod. Should be an interesting project!


#6

Could cleet position be a factor? Another possibility is your knee tracking. I have to wear arch supports in my shoes and my cleats are angled to keep my knees tracking properly.


#7

Oh and if your glutes are really tight or your hips in any way that can actually be the source of the IT band pain as well. If you look up exercises for IT band pain you’ll come across strengthening exercises which helped me a lot.


#8

Cleat could definitely be a factor. Before this past weekend, I had these speedplay pedals that allowed a lot of rotation and I noticed my left knee in particular wobbling side to side - so I’ve changed them out to shimano pedals with the yellow cleats. I’ll see how that feels for a bit.

As for glutes and hips - they are tight and are areas I’m trying to improve and strengthen as well.

Thanks!