Upgrading a Nimbus Trials

Hub/crank upgrade is a must.
New pedals would be good.
Maybe trim the foam in the seat down a bit.

Dont bother upgrading the frame, its not worth it.

Sounds like you’re rapidly outgrowing your Nimbus!, 1.5m drops are probably right at its limit, you’ll break something soon… That of course depends on your weight. I’ve managed a good 8 months of solid work on my Onza trials and have just managed to snap a crank after repeated 4-6ft drops, but I’m a heavy guy with that.

I’d suggest you get a new hub/crankset, which one is up to your budget and personal preference, I’ve got 3 uni’s with the Onza or KH/Onza hub and I love the Q-factor and the small splines on them.


P.S, I think 1.5m counts as a big drop :p.

If you’re dropping 4 ft+ at all recently you’re going to tear that hub in two pretty quickly. It would be well worth swapping to a splined hub and crank set (Koxx, Onza or Qu-Ax) and posibly a better rim. Having the cranks breaking on a big drop can be the cause of serious injury, it’s well worth changing them before they break if you can see that happening. The pedals are ok, but others provide better grip if you’re willing to fork out for them. The frame is as strong as you’re ever going to need, other frames are lighter and stiffer, but to be honest you have to be pretty good before it really makes much difference, it would almost certainly be a waste spending money on this component at this stage.

Honestly, it might be more worthwhile in the long run to upgrade the whole uni.

But, The tire doesnt need to be upgraded, or the frame though, and I doubt you need to change anything about the seat just yet.

Ok sure, if you find yourself with £175+ grab a splined trials uni and sell the nimbus, but it’s probably going to be more financially practical to upgrade as you go, although this will cost you more in the long run.

I think i might need to upgrade the rim. I love the nimbus but today the rim just burst, look at the thread Broke uni


I’d assume thats a pretty isolated incident, its very rare that any rim bursts like that and is probably more down to a manufacturing defect rather than any problem with the rim design itself. The Nimbus rim will be perfectly good for your purposes, and will cope with pretty harsh abuse.


Yea the guy at udc said there was a defective bunch or something but a few might have sneaked through. It is a very good uni though dont get me wrong. :wink:


I think you should upgrade to profiles.

Max, the cost of profiles in the UK is more than buying a brand new splined uni whole. That is not an exageration. Also, because of the cost of shipping the warranty is not nearly as cost effective as it is in the US, KH/Onza or Qu-Ax are a much better idea.

Thanks Loads -A couple of crank/hub questions

Thanks a load for the fantastic feedback! This forums is great!

-forrestunifreak- you are completely right, it would be cheeper to buy a new unicycle right now but i’m not expecting to have £175+ anytime soon :slight_smile: thanks

It sounds like you guys recommend new splinted cranks and hub first. Splinted cranks stronger? Designed for trials?

What are the good trials hubs/cranks at the moment? It sounds like people are riding on Koxx, Onza, Qu-Ax or KH cranks and hubs. Is there any major difference? Does one make specialise in huge drops (Koxx?) or lasting for a long time (KH?). (I’m about 8 stone)

-LooseMoose- Thanks for the comments! You mentioned that you liked Q-factor and small splines. I’d be grateful if you explain what they are to me?

Any help would be super! :smiley:

The cranks on most trials unicycles are bigger than the cranks for my nimbus aswell. Is this recommended? Does it limit the speed you can travel a lot? What lengths of cranks are recommended for street cycling and trials cycling?

Looking forward to hear from you

If you are planning on upgrading your hub/wheel set you probaly are going to have to buy a new frame. The reason for this is becasue both the Koxx and the KH 05 have 42 MM bearings well your frame is designed for a 40MM bearing as such the only one that you could use would be a Profile hub/crank set (maybe Qu-ax i have no idea about them). So i would sort of reccomend just buying a whole new uni and selling that one. I personally love the KH05’s but i have never ridden a Koxx. the KH is lighter however and if your wanting to do trials… totally head for the KH, just my oppinion though… like i said i am byest only having ridden the KH.

Id say the kh hub/crank is the stronest but that all depends of you riding style… search some threads there was a HUGE convo about it…but if I was you, id go with kh stuff not that koxx is bad I just prefer kh… it’s ligher and stronger.

You might want to look into buying a wheelset to avoid the pain of relacing your wheel to a new set of cranks. I would say if you can get it to fit, that’s the best part to upgrade right now, especially if you’re doing any sort of drop on a square taper setup. I bent my cheap norco on a 1.5 foot drop, and I’m amazed you haven’t broken the nimbus yet.

The only thing you need to upgrade on that uni is the crankset. Get a KH crankset. They are light and pretty strong.

The Kh hub will fit in the Nimbus frame, mine has for the last two years. Splined cranks are much stronger, ‘splined’ actually refers to the way that they fix to the hub, but there’s no point in having a strong connection if the cranks are weak, so splined cranks are strong. Most trials cranks are 140 or 145mm, these will decrese your speed slightly but don’t worry about it, they are the best for trials, else the manafacturers wouldn’t make them that size. I’d say go with obie’s advice, get the KH/Onza crankset, you’re not going to break it in a long time. Be aware that if you change the hub you’re going to have to rebuild the wheel, you can do this yourself but it can be tricky to get it straight, so you might have to pay a bike shop. My local charges £25 to build a wheel and £10 to straighten a built wheel. Also the spokes might not fit if the old and new hub are very different, spokes are around 50p each so that’s another £16. Just so you know how much you’re getting yourself in for.

Holy Crap!

I have been having a look at www.unicycle.uk.com

The “Kris Holm Splined Hub and Cranks Set” is £75 :astonished: !!
-kington99- You know for sure that they will fit?

The “Onza Hub and 140mm Crank Set” is £100 :astonished: !!
(would this work with my nimbus trial?)

And the “KH/Onza Hub and Crank Set” is £115
(all on www.unicycle.uk.com)

I really didn’t realise that it would cost so much!
It’s a pain but I know that I will have to upgrade soon, after tightening my cranks this morning they are already creaking very badly only after a few 3ft drops. I think they’re pretty mashed :frowning:

I either upgrade to new cranks (£75-£115) or save up and buy a completely new Trials uni and sell my old one! One was sold recently for $120 US, it was 4 months old and had new cranks. I’ve had mine for a year with the original freestyle cranks. :sunglasses:

How much do you guys think I will get for it? It would be fantastic for learning on, but not great for any more big drops, likely to break.

Are trials Unicycles practically the same (durability) (riding styles)? Is it definately worth riding one before going ahead and buying one?

Any opinions about the trials unicycles on unicycle.com (Onza, Qu-ax, KH, Koxx)? Any one fantastic and worth the money, any one to say away from?

What a pickel.
All opinions on what I should do would be greatly appreciated!

Is the Onza Hub and Crankset £25 better than the KH hub+crankset?
Is the KH/Onza hub+crankset £15 better than and Onza hub+crankset?

Is any one crankset/hub better than the other? If anyone says “it depends on your style of riding” I will scream.


I’ll try and answer as many of your questions as I can:

There is a uni hanging up in my shed with a Kris Holm Splined Hub fitted to a Nimbus II frame. It’s been that way for the last two years. I’ve probably ridden hundreds of miles and dropped cumulatively hundreds of feet in that time on it without any problems. It fits. Having said that you do need to just push the bearings in a little harder than you would with 40mm bearings, and also pull the legs out very slightly. The same goes for the Onza and KH/Onza hubs.

Hub Comparison:
KH - a little heavier than the others, no problems with the hub but the cranks can twist as they are a non-circular cross section.

Onza - lighter than the Kh, the cranks were good but there is a problem with the way the hub fixes to the axle, this can become apparent in quite a number of the hubs produced but can be fixed with some superglue very satisfactorily.

KH/Onza - the strong hub design of the Kh with the strong crank design of the Onza plus a fancy taper widget so they don’t creak when you ride. The lightest splined hub on the market.

All the splined trials unis on the market currently are pretty good, the more you pay the lighter and stronger uni you get, but there’s not that much difference across the board. I’ve ridden all four that you mentioned, the KH and Koxx are a little lighter than the other two but it’s not a big difference, especially considering the extra money that they cost. There are a lot of serious trials riders perfectly happy jumping around on the £175 Qu-Ax. I hope all this is helping you rather than just getting you more confused.