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Should my fork sit on top of the axle of the QR version of the son 28 disc hub or should it sit next to them on top of the QR axle?

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  • Welcome to Bicycles SE. You will probably need to add a couple diagrams or pictures of what you are trying to describe to get a concise and accurate answer to this.
    – Ted Hohl
    Oct 24, 2023 at 9:05
  • It's hard to figure out what you're asking just from a verbal description. Can you take a picture of the product you're asking about, or find one online, and add it to your question, preferably with some annotations pointing out the two different ways you think it might be configurable? If you've already got the product in hand, even better would be to configure it the two different ways you're describing and post a picture of each. If it's not super time consuming to switch between the configurations.
    – SSilk
    Oct 24, 2023 at 9:07
  • Can you please add a couple photos? Specifically the fork dropout with the SON hub in place. Ideally from an angle to show the depths. Also, a second photo showing the axle sticking out of the SON hub, with the wheel out of the dropouts. If that's not possible, please accurately measure the thickness of your front dropouts, and the amount of stick-out the SON hub's axle has.
    – Criggie
    Oct 24, 2023 at 9:46

2 Answers 2

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If I understand the question correctly, it is whether the fork dropouts sit on the hub axle or the QR skewer ("axle").

It indeed sits on the hub axle, which itself goes through the hub's bearings inside the hub, allowing the hub shell to rotate around the axle and make the wheel spin.

The QR skewer's sole function is to provide tension/clamping force and secure the wheel in the dropouts between the adjusting nut and cam lever.

enter image description here (Fork arms added in orange for illustration)

Edit

I cleaned my bike today and as I had it flipped over, I was reminded of this answer and took a good shot of how the wheel sits in the dropouts. Schematic pictures are great but real-world examples make it more clear, even though I can't think how to slot a wheel in the wrong way, at least if the axle matches the dropout width.

(Yeah, I know ... my dropouts are pretty chewed up from taking out the front wheel quite often to get the bike in my car)

enter image description here

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    I think the wording in current version of your answer is ambiguous. Saying that fork sits on the hub itself makes me think it somehow sits on the hub shell which is definitely wrong as hub shell rotates. A picture is correct though, and as it often is a good diagram is worth 1000 words. Just need to draw a clear difference between hub axle and skewer which is sometimes mistakingly assumed to be the axle.... Oct 24, 2023 at 12:24
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    @ArtGertner Yup, I'm one of those users who love the edit function and doesn't do drafts before posting, a bit like I do my job as a software engineer. I removed my doubts and cleared up the wording a bit to distinguish between hub/bearings/axle, I hope that's more concise, now.
    – DoNuT
    Oct 24, 2023 at 12:43
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    Thank you everyone. It turns out my qr skewer was defective. I just ended up buying a non qr axle. I was weary of using the qr one as I was unable to determine the nm of it. It works wonderfully now! Oct 25, 2023 at 10:32
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No - a QR skewer is not an axle and has far less strength than the axle.

Your axle should take the load vertically, and the QR only provides clamping force. That is, the QR skewer is under tension, like this:

enter image description here

Whereas if the weight of the bike rests on the QR Skewer, there is a sheering force applied at the arrow, as per :

enter image description here

At best, nothing bad happens. However a good impact could bend the QR, or worse cut it clean off and then your wheel will cock itself sideways and bind in the fork or frame, and in that case you are very likely going down.


Pictures are concepts. not showing real overlaps. The axle should end just below the outboard surface of the dropout, perhaps 1-2mm to provide clamping space. The QR's nut should not press on the end of the axle, only on the dropout part of the frame.

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    Thank you so much! I finally got it. Turns out my qr skewer was defective. Oct 25, 2023 at 10:27
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    Note that QR nuts have a recess in them so even if the axle is flush with the dropout, the pressure is sure to be on the dropout
    – Chris H
    Oct 29, 2023 at 9:58

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