As per title is there an online tool that you can put a gpx file in ( with cadence and road speed ) that works out what time you spent in what gear.

Cant find any thing so far ?

The aim is to then work out what casette I need to go with the new cranks to not only get the gear range but to make sure that I am not forever cross-chained

Thanks

Look at the cassette what looks mist worn?

I use this

http://gears.mtbcrosscountry.com/#26I1I1

Could you not just look at your speed/cadence up the steepest climb and see if it’s way off?

Then see if it’s possible to optimise your average speed at ~90rpm to be the middle of a cassette in the big ring.

Thanks – what I am looking for is indeed the most worn sprockets , just it does not show up yet.
The gear calculators are good for working out when you are going fastest and when you are going slowest but it is hard to pinpoint those gears for a little bit uphill.
I downloaded a commute from strava and it gives power cadence and heart rate – but not speed?!
will try to look at the fit file – but you need a viewer for that

I think it depends on the file format whether it records ‘speed’ or not, some just record time/position and the software calculates it. If you can download the file then just change it from .fit or .gpx into .csv and it should then open the raw data in excel.

TBH though, surely you can just go for a ride and know if you’re always stuck switching between the chainrings or cross-chained?

Feels like there are a lot of variables – traction, the effort you’re putting in, steepness, etc – woul dbe hard to pin down a gear