I ride a Santacruz TRc, its a small and I’m 66″, 5’5″. Santa cruz put me in a nice gray area between small and medium frames.

So which should I be riding ? A small or medium ? does it matter ?
Anyone else in the same boat where there in the middle/between sizes, which way did you go, bigger or smaller ?

cheers.

I’m 5’11” and bought a large giant anthem as my first proper mtb 4 or 5 years ago. I was between sizes too and wish I’d gone for the medium. The large is perfectly rideable but it’s not as manoeuvrable as like, putting a short stem on has helped but I now know the medium would have suited the type of riding I do much better.
On this basis I’ve gone to the smaller side of the grey area on the next two bikes I’ve bought and been much happier with the sizing on them

Size based on height is next to useless except for ball park. It depends on leg and arm length. Compared to road bikes where standover is closer to height most modern mountain bikes are lower with generous standover so reach is the most important figure. After that the reach gets more complex as seat post angles can extrapolate the whole thing.

Sitting on bikes is the best method.

thanks chaps.