There are various fit systems such as Serrota, Guru, Retul, and Specialized BG. Any opinions as to which of these fit systems is considered the best? Thanks

Buying or have bought a High End Race Bike & want optimized competitive performance, You may feel the need ..

I never have , I just self examine my relative comfort and change a few Parts with My Money.

The one where you get the fitter with the best judgement.

It has more to do with the experience of the fitter than the tools they are using. You will likely get a better fit from someone with a lot of general experience using a tape measure and level, than someone who's only experience is the training they recently received on their new fitting equipment.

I have been considering Retul and whatever Trek's new computer fit system is (or at least, the one used by my LBS who is the big Trek dealer in town), simply because I've had some nagging issues that I haven't been able to get rid of in recent years. Not really any pain, but things like my pelvis rotated at an angle on the saddle, sit bones not centered on the saddle which has caused some bad chafing issues, etc. I just need to come up with the money to get it done.

Shop around for the best fitter, not the best system. A "system" is only as good as the provider.


-Kedosto

How does one know when they have the best fitter?

I have seen the same person fitted very differently using the same tools for the same bike purchase, wildly different.

You should read this article (mild coarse language) where the blogger talks about fit systems.
https://tomdemerly.com/2016/04/07/10...-full-of-****/

Total agreement that it's the fitter not the system. Go to three different systems and you'll end up with three different fits. Every single system out there relies on interpretation from whoever is doing it. Ask others about their experience with particular fitters as opposed to trying to pick the best system. Your fitter should chat you up and learn about your physical shape (mine went through a series of stretches to determine how flexible my muscles and back were and talked with me about my experience, goals, past history, etc) and learn about your needs. Some of it's obvious but sometimes it's not done. Anyone that simply puts you on a bike and starts adjusting isnt' worth your time. There are some folks with paricular issues like knee pains and foot problems that require real expertise, well beyond even a good "regular" bike fitter. Look around...chat people up...find a place with a good history and reputation regardless of the system they use.