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first of all I would like to point out I have looked in previous threads here but could not find the answer.

My frame specifications have the following measurements in regards to the rear thru axle:

12×142
172mm long
1.75mm pitch
19mm thread length

it seems like I can not find a thru axle that matches these specifications. The "closest" 2 candidates I have found were:

Option 1: A 20mm thread length axle (but still 172mm long)

Option 2: A 174mm long (which is 2 mm longer than the specification) axle, with 19mm thread length.

Would the one with 20mm thread length work? Thank you very much, would appreciate any advice on this.

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  • Welcome to the bikes SE! Is the title correct? Thread pitch means the distance between threads, but the post describes a difference in the length of the threaded section. Also, it could help to include the make and model of your bicycle; many TA search engines list by bicycle rather than by dimension.
    – Weiwen Ng
    May 1 at 11:27
  • Thank you very much @WeiwenNg, I fixed the title!
    – yuvalon
    May 1 at 11:31
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    Have you tried robert axle project If you contact them directly they might be able to accommodate your needs.
    – Kibbee
    May 1 at 12:27
  • I will contact them right away. Thank you @Kibbee.
    – yuvalon
    May 1 at 12:40

1 Answer 1

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Assuming you still have the original axle, use a visual check to see if the proposed axle will work.

  1. Remove back wheel
  2. Insert axle and thread finger tight into place so that it’s not compressing the stays. You can measure the distance between the dropouts with and without a wheel to double check.
  3. Observe and measure how much, if any, free thread is exposed on the inner drive side.

The proposed axle is 2mm longer with 20mm of thread so you’ll be loosing 1mm of working thread (18mm vs 19mm). If your original axle exposes less than 1mm of thread on the inside then the proposed axle probably won’t work.

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  • Thank you very much Warren for the detailed explanation. In my original post I was talking about 2 different options I had found, so one with extra thread length, but same total length, and the other is the same thread length, but different total length. I had fixed it now. Can I conclude from your answer that the one with "extra" thread length would make a good candidate?
    – yuvalon
    May 1 at 13:07
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    I’m not a materials scientist but having extra exposed axle thread shouldnt provide a stress riser at the dropout as the hub will be resting on the end caps and the inner dropout shoulders . The axle tensions the back end together. Also consider an old school QR axle where the fork/dropout rests on the threaded section of the axle. Their failure mode isn’t normally at the threads. In any case the strength of a thru axle will be far greater than the load you are placing on it. TLDR I’d use Option 1 on my trail bike with no doubts about breaking the axle.
    – Warren Burton
    May 1 at 16:52
  • Use the 172mm axle with 20mm thread length.
    – Jeff
    May 4 at 16:28

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