Triple to Double Conversion and Chainline Adjustment

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mvnchi

New Member
First and foremost hello!

This topic probably has been seen and talked over and over. At least that's what it appeared to me when searching.
Sadly i couldn't really find any answer to my questions really from reading the dialogues.

SO.. on my old Gazelle V3.0 Roadbike i got a SRAM Elita Triple 50/39/30T 10-speed currently with a 12-28 casette and was planning to convert it to a double because unless i would approach really steep and especially longs climbs i would almost never use the granny gear.
My idea was to turn it into a 50/38T with a 12-30 casette which would give me a transmission ratio low enough to still be able to climb most hills here. Also the gear steps would fit me better.

Using a online gear calculator i was looking at the following:
  • Green Numbers are suggesting no chain skew/rub, yellow numbers are duplicates and red numbers are forbidden sprockets.
  • With the 50/38 12-30 i would (theoretically) get almost down to the same transmission ratio of my 30T granny gear.
  • They are calculating with a wheel circumference of 211cm
1756067832223.png

But since i was planning on keeping the triple crankset the chainline would remain unchanged.
Meaning that the 38/30 Gear for example would be "forbidden" unfortunately.
1756068618386.png


Another idea was to do it the other way around. A 50/36.
So dropping the outside 50T and getting a 50T as inside/middle chainring and replacing the granny 30T gear for a bigger 36T. Then in theory i would get "lower" ratios and down to the largest cog.
But in return i would sacrifice the 50/12 which i don't really want to as i tend to spin out quite often going downhill already.

So sticking to the initial idea of going with a 50/38 12-30 and the triple crankset - is there anyway to still be able to use the 38/30 and get the chainline somewhere so it is like the mid table?
Would i need smaller bottom brackets? Is it anyways always going to case chain skew/rub due to cross chaining? Or am i completely wrong here?

Anyone willing to sacrifice some time for my nonsense.. thanks in advance!
 
Last edited:
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mvnchi

mvnchi

New Member
Additionally a picture of the crank

1000005381.png
 
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