VCX Nimbus cranks

Hi there

My thoughts on the new VCX cranks (Nimbus):

Lately I have been using a pair of Quax 145mm cranks (which I had lying around from a QuaX Muni) in my Trials Uni so I could learn to do some crank rolls (they’ve got a nice big chunky/wide arm which I think makes it easier to stand on the crank). I found the length (145mm) a bit too long so I was thinking in getting something slightly shorter ones (as I am also working on my Trials skills). I’ve noticed that Unicycle UK is selling now the new VCX (nimbus) cranks in a wide range of lengths. I’ve got myself the 138mm cranks and I have to say that, as far as I can tell, they are great cranks and I think they are quite good for standing on them when trying to do cranks rolls and other crank based tricks (I am still trying to master them!).

I’ve noticed that the ISIS interface in the VCX seems to go slightly deeper than the previous Venture II cranks and their fit into the hub seems much tighter (good news in my opinion).

With this in mind I have also bought a 125mm pair for my 36 Oracle: the hub is a bit worn, and the 125mm venture II cranks (practically new, they originally came with the Oracle) I was trying to fit back into it (after using the KH spirits for a few years) were bottoming out and were too loose to ride without the risk of damaging the hub. I have to say that the new VCX cranks fit nicely and tight into the hub. So if anyone else have the same problem with their hub/cranks they might want to give these cranks a try rather than replacing the hub…

Cheers :slight_smile:

They require 7mm spacers instead of 6mm (confirmed by Roger Davies)

Hallelujah! The venture 2s were creak machines because they were not snug enough at the hub. A quiet drivetrain is a wonderful thing!

I asked on UDC UK’s YouTube channel about this. This is their response: “They are designed to only need a 6mm spacer on most hubs.”

Reply by mail from Roger Davies Nimbus/Impact/UDC CEO :

Hi Didier,

Yes, we moved the tolerance back to where it should be. We are supplying them on the unicycles with 7mm



I installed 7mm spacers after reading your previous post. I guess I’ll keep them on then.

I had my first ride with my new VCX 138 cranks on the 36’er yesterday, and like Moslki said they seems too be a tighter fit than my old Venture cranks. No creeking at all, when hopping or going off curbs. I’ve used 150 cranks on my 36’er since I started riding in 2010. I tried 125 cranks once, but didn’t like them, because I felt I lost control and it was too hard up hill. The 138’s were different - full control and a lot smoother than the 150’s. I struggled a bit on my “benchmark hill”, but I will keep them on for sure.

When replacing nimbus venture 2 crank with the new vcx cranks do i use the same spacers ? I cant get the venture 2 tight enought on the oracle impulse hub (new hub and new crank). Would they fit more tight against the same spacers or do they need to go deeper to be more tight :slight_smile: ? Thx !

If the crank bottoms out, and the bolt head tightens against the axle, you’ll need to increase the spacer width. The bolt head should tighten against the crank, and when you tighten it up, the whole thing should end up tight.
Changing crank spacers is a topic that should, perhaps, be given more forum time. I think it’s relevant, because cranks are different!

Good luck! :slight_smile:

Just received the Vcx cranks in the mail. They are way more tight than the venture 2 on the isis hub. I use spacers 1mm thicker than i did with the venture2 and the vcx crank really press on that hub! I get them pressed 3mm past hand tight and there is still a whole lot of shoulder on the crank for the isis bolt to push on ( that the venture2 didnt have ). They deffinately wont come out by wiggleing them like the venture. Verry happy :slight_smile:

Maybe I am not understanding correctly, but is there still a gap between the crank and the spacer? If that is the case, you may need wider spacers. The ISIS standard calls for a crank stop, meaning that the final tightening of the bolts locks the spacers in place, without a gap. Sorry if I am misunderstanding. I had a lot of confusion about this issue as a novice. I don’t want other people to make my same mistakes.

That might tempt me into getting them. It was my third ride on a brand new 32" Nimbus, and the right crank is creaking on mounts and acceleration!

I have something similar on left side I think, I was thinking of bearing holders (I have Mad4One cranks)

Oh no!
I have a pair of cheap 125mm straight cranks, I might try them on next time to see if it creaks or not.