i think it depends on you and the events you do. i did the change on my TT bike 2 years ago as i couldn't remember the last time I'd used the small ring, At least for the events i do the organizers want broad participation and aren't likely to stick a hill in it that i can't climb with 52 on the front and a 26 or 28 on the back and still keep the cadence reasonable. i also don't do IM or 70.3 which helps; and rarely just ride miles on my TT bike so encounter limited gradients in training.

However, i didn't change the crank. i just took off the FD and inner ring, and replaced the outer ring with a narrow wide.As i had a 130 the smallest i could go was 52. if i had the option to go to a 50 i would have done. it would just be a better fit with my power, weight, cadence preferences and events. think about what you are using now, and how often you have had to change down to the small ring with whatever large ring you have and i think you will know the answer to 52 or 50.

I would say it really depends on your cadence. If you tend to grid a bit going uphill, then 52. I find that I spin out my 50 going downhill on a lumpy coarse so the extra 4% higher gear ratio is nice. Technically the 52 will be slightly faster doe to less friction.

Depends how low a gear you need. In the end it really doesn't make a big difference.

A 50x28 is slightly smaller than your 38x21
A 52x28 is slightly bigger than your 38x21
A 46x28 is the equivalent of your 38x23
A 52x32 is the equivalent of your 38x23

Just go to Sheldon Brown's gear calculator - enter what you have and what you want (e.g. the 1x setup). It will show you the ratio differences. Then just decide on what you'll gain vs what you'll lose based on your needs (e.g. course). Or just buy both front chain rings and try them out. Swap/setup isn't super tough. P.s 1x is pretty awesome :-)

Thank you :)

Think i will go with a 52t in the front then.
If 1x is a success for me, but feel i need a lower gear i will change to 11 speed either Ultegra or Sram 1 with a 11-32 cassette :)

Cheers
Kristian

I went from a 52/36 and 11-28 to a:

50T and 11x36 for training with a SRAM Wifli and a Wolftooth Goatlink (https://www.wolftoothcomponents.com/...ll/products/goatlink)

I train in an area with a lot of hills.

For races, I use 50T or 52T depending on how hilly the bike course is with an 11-32 cassette.

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2018 Races: IM Santa Rosa, Vineman Monte Rio, Lake Tahoe 70.3