Hello everyone. I need advice. Now I use to 48/32 11-34 and want to change to 1x. I found a light weight cassette ZTTO 11-46 slr2 on Aliexpress and I want to try to buy the chainring to it. Of the available ones, there are mainly up to 38t. Tell me, is this chainring enough for high speed on a small chainring and good ability in bikepacking climbs?
I suggest using a gearing calculator. One I've loved has been down. It stood out for comparing setups side by side. I was happy with a stock 11 speed (42 rear) and 36 front on a bike packing setup but that's me. Over time I stuck with our a gravel and off road tourer with 2x because both types of bikes can cover such a range of riding. I stand pretty firm that you need to use a gearing calculator with bikes you know and your riding in mind to figure this out.
First, are you happy with your current 2X setup? It has a 4.36:1 high gear and a 0,94:1 low gear.
Your proposed 1X setup has a 3.45:1 high gear and a 0.83 low gear, a narrower and lower range than what you have now. If you want to approximate your current low gear with a 11-46 cassette then you'd need a 44T chainring (43T is closer but probably not available). If you want to equal your current high gear than you'd need the same 48T chainring. To split the difference use a 46T chainring.
You can find cassettes with a wider range than 11-46 but you'll have to consider the rear derailleur and whether you want a tiny 9T or 10T cog. If you're set on 11-46 my suggestion is to try it with the 48T chainring you have now.
@stu has spelled out the numbers perfectly, but I wanted to add that you should be able to find the larger chain ring you need to match your current gearing. What is your current crankset? I have used 1x for all of my bikes (including road) for many years now. For my road bike, I used a 50t ring with 11-40t. 48t sounds right if you are sticking with the 11t cog. If you have an option to go to XD/XDR cassette (i.e. you need new freehub body) then you can find 11sp cassettes from SROAD or probably also ZTTO in the 10-42 size in which case 46t or 44t would likely be plenty of top end.
For chain rings, you likely have many options. Get a narrow-wide ring. From AliExpress I like PassQuest rings a lot (you can order directly from their website too). SRAM X-Sync and Wolftooth are excellent, but also more expensive. Whatever you get, you'll need to make sure you get the chain ring that pairs with your crankset spider bolt-circle diameter (BCD) (and, of course, number of bolts).
