I've bought myself a little city bike a few months ago and since we're now approaching winter months I will need to install some lights to ride in the later hours. I've been toying with the idea of installing a dynamo hub and matching lights.

As far as I understand installing the hub itself would require me to completely rebuild the wheel, which I do not feel comfortable doing. I've noticed that some online stores are selling entirely prebuilt replacement wheels (e.g. here), which would suit me much better.

However, I have no clue what kind of wheel / axle system I have and all my research left me at best unsure and at worst completely confused.

I took some photos of my front wheel. Would anyone here be able to help me identify my wheel size and axle type, such that I can buy the right parts?

I believe I have a ISO 622/700C wheel. At least the number 622 is printed on the tire. However, I also see 28 there and I read that ISO 622 should be 29 inches, not 28. So I'm not sure.

In terms of the axle it seems to be neither a through axle nor a quick release, but something in between? I haven't taken the wheel off yet to give it a closer look, but it appears like the axle itself is held on the fork by a nut on each side. But then the fork is open towards the bottom on both sides, too, like a quick release would be I believe (you should be able to make that out on photo 3 and 4). So I'm super confused here.

Imprint on wheel Axle above Axle side Axle below

1 Answer 1


That wheel has a solid axle. I prefer to think of it as a nutted axle for obvious reasons.

It's cross-compatible with quick release, and quick release is easier to buy, but the sort of hub you have is cheaper to manufacture. So you can get a quick release wheel. Make sure it comes with the skewer that holds it in, or buy a skewer. Security skewers from companies like pitlock and pinhead make stealing the wheel harder and are a good idea if you're locking it up outside. I've swapped a QR wheel to one like yours, because the dynamo hub I got for free used nuts.

Now welcome to the wonderful world of wheel sizes. The one to trust is the ISO size, because that 622mm diameter is a crucial one, and it's defined by a standard. That size is marketed 700c, 29" (on mountain bikes, which might have wider rims), and 28" mainly by German tyre companies. These old/ marketing sizes are based on a notional outside diameter of the tyre.

The wheel you want will probably be sold as a 700c QR dynamo wheel, for rim brakes (there's no sign of disc brakes).

  • 1
    I appreciate you concise and clear answer. Thank you so much! Commented Sep 30, 2023 at 15:09

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