How to measure a hub?


I’m looking at a replacement hub for my muni, and obviously I’ll need one that has the same measurement between the bearings as my current hub. But I’m wondering if this is a standard, or if it varies from hub to hub. I currently have a hardened Suzue hub, and I’m hoping to replace it with a Koxx-1 ISIS splined hub. Does anybody know the measurement of this hub, and the bearings it uses? Is it the same as the Suzue?

Thanks for any help. BTW, I tried the search before posting, but didn’t find any useful results.

The koxx isis hub has 42mm bearings and the Suzue has 40mm bearings

you can find a diagram at the bottom of this table on where to measure hubs it also gives the sizes of the Isis hubs but not the Suzue


If you have a steel frame, you can flex the fork in or out a pretty good margin. If you need a 40mm OD for your frame, the Torker DX bearings will work if the Koxx takes a 20mm ID.

Koxx Bearings are 42x12x25, I have updated that on our specification for the hubs.


A clarification …

Thanks for the info so far. What I’m really wondering about, though, isn’t the bearing size (although that’ll certainly matter, and I hadn’t yet thought about it), but the distance side-to-side between the bearings. That is, how wide is the hub? Is that the “bearing spacing” measure on Roger’s site? I want a splined hub to fit my steel Telford frame, which (as I said) currently has a Suzue hub. I don’t know if the Koxx or other splined hub will fit into my frame’s bearing holders. I can measure that distance but probably wouldn’t be as accurate as a manufacturer’s spec. I suppose that if it’s relatively close to 4" it will likely work with most of the hubs listed–since it’s steel, it will have some give. I guess it’s the available bearings that may make or break the possibility of successful upgrade.

i believe that the koxx isis hub bearings are 100mm apart, centre to centre of the bearing. i am not 100% sure of this, you may want to check it up. you can measure the distance of your frame bearing holders by taking the wheel out, and measuring the distance between the middle of the bottom parts of the frame.