What is "Standard 100mm spacing" ?

Or perhaps, more accurately, I should ask Where is standard 100mm spacing taken from?

Looking here;
I can see that this hub has standard 100mm spacing, but is that from the outside edges of the bearings? The centreline of the bearings? Tip to tip of the axle?

I know it sounds like a newbie question, but I’ve just spent about half an hour on google trying to find out the answer.


In a rational world it would be the distance from bearing center to bearing center. We live in this world so it could mean anything. I mean, after all, UDC redundantly calls cranks crank arms and calls aluminum alloy while not specifying steel as an alloy.

Thanks for the clarification… only now I’m more confused than ever :thinking: Not sure if that was the real answer, or an American version of irony. I think if I lived in a rational world, I’d ride a bike just like everyone else… but then again…


I just measured my 07 KH

I took off the bearing caps, and measured 112 mm from outside to outside of the bearings, using a mechanics caliper. Since they are 12 mm wide, that makes them 100mm from center to center.:slight_smile:

I used a haberdasher’s caliper and got the same reading.

I used my thumb and got the same result.

(Yes, it usually means bearing center to bearing center.)

M understanding was always that it was from bearing centreline to centreline. Of course you could have saved that half hour by just phoning Roger, who would have told you in about 15 seconds.

Yeah, and then he would have persuaded you to do something silly like buy something, or organise a hockey tournament :P.

or BUC. :slight_smile:

Thanks guys,

I thought it should have been centre to centre, however, I measured the width of my Schlumpf hub, and it was 101 from outside to outside. I though the hub was standard, so then began to wonder what ‘standard’ was. Hence the post. Turns out it’s not quite standard, and is on 89mm centres.




On that basis… I think my time has been well spent using google instead :smiley:


You are safe, you are in the US.

BUC = British Unicycle Convention.

Although that being said… it could be fun.


I bet Sam would still chose to ride all the way there though!


Can you get pedalo unicycles from UDC?

No. That is not a name I know either.


I don’t believe they make unicycles, but they do make a ballance trainer.


At UDC UK they have Fun Wheels, a much less expensive brand (it also apears to be less durable)

There is also the easier Double Pedalo, the Pedal Go,

and the much harder Ultimate? Pedalo - for learning to ride an UW.

Phew! I’m glad someone else has noticed this too… call me a stickler for detail, but ferchrissakes, if you’re going to call something an alloy, you better start naming ingredients!

Put simply, “alloy” means “mixture”. What good does “alloy” do for someone who’s shopping for, say, a set of steel cranks?


rips hair out

No, no.
This type of pedalo.

I was making a joke about Sam riding across the Atlantic.