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Not having a great day 1st freehub now this. So the hex screw holding the cable on the front derailleur has sheared off, leaving a piece in. So needing a new derailleur but I see when ordering one it comes in a couple of sizes 34.9mm & 28. 6 / 31.8mm. What does this relate to and how to know which to order

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The _Kaner [1194 posts] 1 month ago
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That is the band-on diameter size. You will need to know the diameter of your seat tube, so you can look up the bike spec and go from there, or if you have a set of vernier calipers you can measure the seat tube and select the correct  one. Failing that you can wrap a tape measure around the tube and use diameter = circumference / pi.

Just make sure it's a band on type you need and your frame isn't braze on, then you'd need to select a braze on version.

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The _Kaner [1194 posts] 1 month ago
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Band on

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The _Kaner [1194 posts] 1 month ago
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Braze on

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rob39 [23 posts] 1 month ago
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It's braze on should have said that

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The _Kaner [1194 posts] 1 month ago
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If it's braze on then there is no diameter size, you must be looking at the wrong type of FD.

Look for a braze on FD.

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ChrisB200SX [1011 posts] 1 month ago
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Order the 5801 or R7000 or R8000. They are supposed to be a lot better revised mechanism.