Question about UDC Hub

Hello, first I’d like to say that this is a great site. I’ve been using the search for the last month or so for all of my questions and most times, there is an answer.

I’m wanting to get my first unicycle but did have a question. I have been looking at the UDC Club uni’s and would like to know if any of you guys know if the hub is CrMO or not. When I searched on it, some people say they are, some say they aren’t. UDC’s british site says the hubs are CrMO but the US one is a little vague.

Also, how easy would it be to upgrade the hub to ISIS down the road if I decide to do anything more technical than just riding around my yard? I think I saw some KH bearings that would allow the use of an ISIS hub in 40mm bearing housings but set me straight if I’m wrong.

Thanks for the help. It’s very much appreciated.

The hub on the Club Freestyle is not CrMo. The only CrMo hub fitted to a club unicycle is the one fitted to the 19" club trails unicycle.

It is worth pointing out that the steel used in the hub fitted to the club unicycles is not weak like many fitted to cheap unicycles. Its failure rate is extremely low - the UK had only had one failure in the last 12 months!

The KH bearings for fitting ISIS hubs to none ISIS hubs is this one:

It does solve the problem but is proving not to be an exceptionall durable item and is difficult to install. You need to be very careful when fitting the spacer to be sure it does not imping on the bearing shield.


Awesome! I think I’ll definitely be picking one up. Thanks for the help!

One more quick question, would doing small hops like stairs (one at a time) be problem at all for this hub? Or should I just keep it on the ground? Most of my riding will be around the yard or some light trail, but I wouldn’t mind being able to go up and down stairs on it eventually.


It is CrMo says hardened steel. I wouldn’t bother upgrading a club uni to ISIS since it is an entry level cycle and with ISIS hub and cranks it will still be entry level with ISIS. Personally I would keep the club as a freestyle or leaner spare unicycle and buy an ISIS one seperately- hopefully before bending your soft steel cranks.

So in your opinion Roger, why are the UDC hubs not weak like the cheap unicycles, if they are not made of Chromoly? What magical material are they made of that is not hardened steel that is harder than steel and is cheap like steel? The good news is the hubs are relatively strong!

One step hops are fine. You can bend the cranks by jumping down a few steps and landing badly- with correct technique it may not bend but I would advise caution and sticking with one or two steps at a time to prolong the life of it. Hopping stairs is a useful skill that you shouldn’t miss out on.

If you think you may get into a lot of hopping it could be worth buying ISIS to begin with, depending on your cash pile and how soon you would want to upgrade. Everyone is different- I think you can never have too many unicycles so get both!

Thanks for the help! Maybe I’ll look at something more like the Nimbus II. I know that will be better, I just don’t know how much I can spend right now. Maybe a club first and Nimbus in a few months down the road…

Ok maybe I spoke too soon as my freestyler unicycles are not with me. I have an axis unicycle with CrMO hub. Of course Roger knew better than me- sorry Roger. I wonder if they heat treat the Club freestyler hardened hub to make it harder than normal, or if it is case hardening.

Freestyler hubs are strong enough for their purpose- maybe they are not as strong as Chromoly.

For entry level freestyle I’d go with the Club rather than the Nimbus II with ISIS- cos club will serve you well til you decide you need a MU, a trials or a 36".

Club Freestyler hub.jpg

Perfect, thanks for the help! I think I’m still going to go with a Club. Just need to decide if I want a 24" or 26" wheel now. I know the 24" would be better for freestyle and easier to learn on but the 26 going a bit faster sounds nice. With the club I can at least learn how to ride and figure out which direction I want to go with it…

Right now, ultimate goal is a 36" Coker someday.

Thanks again for the help both of you guys! Very much appreciated.

is there anyone you can barrow a unicycle from?

None that I know of…

if you did you could barrow one then save up for a nice muni or trials or 36er

It is a mistake on their site, I will ask them to change it. The hubs on the Club are not CrMo, but are a high carbon steel that has then been hardened.

There are thousands of types of steel and also many different CrMo steels. They are all have slightly different in their composition this gives them different characteristics. These are further changed by the way the steel parts are constructed and treated. The hub on the Club unicycle is made from two steels, one for the flange and one for the spindle. They are hardened after they have been constructed to give them an appropriate harness and toughness for their use. The number failures confirm this is the case.

Why is it better than cheap hubs… I don’t know what material they are made from but it is certainly not hard or tough and I very much doubt that they have been any where near a hardening oven! (This I also suspect goes for some of the cheap ISIS hubs we are seeing now). We tested a whole pile a few years ago and had figures for the cheap hubs at below 150 Vickers. The Club hubs are somewhere around 400 and the CrMo ones are about 580.


Rowan, would I be better off if I got some better cranks for it?

Also, wouldn’t I be able to completely revamp it at some point with new seat, seat post, rim, hub, and everything being as the frame is a nimbus? Or would even that still be an entry level uni?

Roger, pardon the ignorance, but could you explain how much a Vicker is?

Thanks guys!

I don’t think it is a mistake on their site, it is more like a mistake with my sight reading their site- sorry. I must have remembered that it was hardened and mistaken it for the same thing as Chromoly- knowing that hardened is better than the ones that break easily.

I don’t suggest replacing all the parts- which is why I would choose a UDC Club over a bike shop or trademe unicycle. And also why I would choose a splined one first if I intended heavy use rather than buying a square taper and breaking it and trying to replace all the parts as they fail. Breaking your unicycle sucks, especially when it is your main one.

Sounds like the club hubs are plenty strong for their intended purpose.

Alright, I think I’ll pick up the Club then and when I get better I can decide wether I want to upgrade or not, I can try some different things and see what I like.

Besides, after adding up the cost to replace all that stuff, I’d have just about enough money for a new Nimbus anway!

I definitely think the Club will be perfect for right now though and I can’t wait to get my hands on one…

Thanks to everybody. You’ve all been a big help!