Making custom Cassette

H.

I am now two years into this road cycling “thing”.

Minor background:

Completely hooked (and yet another reason to buy gadgets) 🙂

I aquired a Canyon Endurace CF SL 9.0 bike (2017 model) and it was equipped with the Ultegra groupset (6800)

50/34 chainrings and 11-32 cassette. All is fine. BUT….

after two years and quite some four digit total miles on the bike I find the gear “spacing” (<– excuse the lag of proper terminology) to be a little akward in the most used gears on flat-ish roads.

I looked at the dealer manuals from Shimano for both the 8600 and newer R8000 groupsets and they seem to be interchangeable.

———-

Dillemma:

I really would like a 15T cog as I find the 14->16T jump somewhat large. I could “just” get stronger of cause… 🙂

As of now I have 11-12-13-14-16-18-20-(22)-(25-28-32T) cogs

I very rarely use 11T and 12T (12+13T at downhils, but again. They are mostly untouched

I notice from the shop manualt that there are now a 11-30 cassette from the R8000 series.

Could I combine it to the following:

12-13-14-15-16-17-(19-21)-(24-27-30)  —> () incicating the fixed cogs on the spider assembly

This would be simply great in a number of ways:

12T would still not be uset much but prevent cross chain stress AND I would get my 15T cog.

32T vs 30T is not that concerning for me.

I did type this into an online gearing/rollout sharting calculator and t looks OK.

CONCERN:

Will it shift properly. I can see from the shop manuals that the same cogs are not available from each cassette. They are market A B and C in the manual and am I right in assuming this is due to the machining of the cog to assist in shifting. ?

Please advice (and sorry for the lengthy post)

Regards

Allan

Denmark