Rear dropouts rebrazing from QR to Thru axle?

Hi, everyone! I’m not a framebuilder, but plan to start building frames as a hobby in future. I have a steel frame with QR rear dropouts, is it possible to convert QR to Thru axle? I understand that it will require change spacing and rebrazing. I couldn’t find any info about this procedure. Have somebody done this?
I imagine this order:

  1. change spacing drom 135 to 142
  2. unbraze QR dropouts
  3. miter chainstays for thru axle dropouts
  4. braze new dropouts
  5. align geometry
    is it correct?

I know that profit of converting from QR to thru axle is doubtful but want to know is it even possible:)

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It’s definitely possible

Make sure to take into account the dropout lengths and how they interact with the chainstays AND seat stays.

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It’s definitely possible! Something that would help a lot is choosing new dropouts that are physically larger than the existing ones. That way you’re cutting to fit the new dropout instead of having to redo the entire rear end of the bike. You might not have to do step 1 since many dropouts take that the extra 3.5mm lip of 142mm axle spacing into consideration already.

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A photo of what you are working with would help a lot. The more chainstay material the more flexibility you have.

What is the brake situation you are working with?


Here is an interesting video showing one approach to modifying an old steel QR frame to work with thru-axles.

-Jim G


Fun! Although for the effort it sure makes thru axle adapters look cheap haha. I guess if ya goin to the effort to bastardise an old frame with IS tabs then converting it over at the same time isn’t the worst idea.