13-34 "custom" cassette on Claris. Will these parts play nicely?

Question

I ride a 2019 Salsa Journeyman. I have Claris 2x8. front is a 46/30 FSA chainset, rear is an 11-34 Sunrace 8-speed cassette [11,13,15,18,21,24,28,34].

I want to pickup a Miche 13t first position cog and the Shimano CS-HG50-8(bf) cassette [11-13-15-17-19-21-24-28T]. I want to remove the 11t and 13t from the Shimano cassette, add the Miche first position cog, and the Sunrace 34t cog, and ride away to the races. Not, the races, though. The leisure gravel rides for days with gear.

Is that going to work or is it a fool's errand?

Answer 1

From how the question is asked I presume you know the more metalworkingish parts of hacking cassettes, like grinding the rivets etc.

The internet shows mention of the existence of the Miche 8/9-speed Shimano first position cog. It has a built-in spacer and the spacing between 8 and 9 is different, as is the typical cog thickness. Therefore I don't see how that product can do its thing without requiring the user to mess around with microshims in the 8-speed installation. Miche's own info seems to show different part numbers for the 8 vs 9 speed versions, which makes more sense, but doesn't seem to bear out in what's actually available. All that said, maybe it would be great, I don't know what exactly would happen if you do what you propose.

You could buy CS-HG50-8's in 13-26 (13-14-15-17-19-21-23-26) and 11-34 (11-13-15-18-21-24-28-34), take out the 14 from the 13-26 and then use the 13-15-17-19-21 from it and the 24-28-34 from the 11-34. You'll have two spots where the exits and ramping won't be "as intended," but that's also true with what you propose, and this way other than those considerations it will all just work because the spacer thicknesses and material stock etc will be exactly the same.