Qu-Ax lightweight ISIS cranks and hopping

I’ve managed to knacker the pedal threads on my Nimbus Venture cranks (learning to ride backwards - though I’m still doing more forwards riding, so hadn’t realised it would be an issue and forgot to check). I have some spare Qu-Ax cranks of the same length, but they look fairly flimsy and this is on my “trials” uni - I don’t do big drops, but I do hop steps and maybe do 1-2ft drops occasionally. I’m probably just under 80kg (175lbs) at the moment, and shouldn’t get any heavier.

So will the Qu-Ax cranks hold up? Has anybody used them for such things? According to the description is looks like I’m within the recommended usage, but would rather not break them (though I’d also rather not spend money on new cranks right now if they’d be OK).

I use 114mm quax cranks on my trials and they hold up fine for me. I have hopped off of some decently tall stuff (4ft ish), and they still seem straight. However, I am 135lb and tend to run low tire pressure, ymmv.

Another option could be to take the Ventures to a bike shop and get them to retap/helicoil the threads. Idk the price on that, but labor wise it isn’t too hard.

I’m heavier than you and I’ve been hopping and bouncing on a pair of those cranks since early 2014 on my Impact Reagent, no probs so far.

Yeah, I used to think that too. :wink:

If you are talking about the soft Quax Aluminium cranks I have broken 3 pairs of them playing hockey in which I do minor hopping. They tend to stress and then crack midway along the length.

I weigh between 88-92kg but they are used only for hockey no drops or trials of any sort.

The light weight QuAx aluminium cranks are made from a softer grade of aluminium than the hardened 6061 that the Venture cranks are made from and are not suitable for any form of jumping.


I have vroken 2 pairs of light weight aluminium qu-ax crank, I have to say that they dissapointed me a lot.

Quax definitely snap more often than the ventures however I still prefer to ride them over ventures and they are cheaper

Hmm, a mix of answers there - was all set to fit them after reading the first couple of replies, but are there two different types of Qu-Ax cranks? I’m sure the ones I have are the lightweight ones (they came fitted to a Nimbus 29er road uni).

The thing is, the description on UDC UK says “designed for beginners trials, cross-country and freestyle riding (not recommended for heavy jumping)” - if they’re suitable for trials at all then that seems to be at odds with what Roger is saying, and I’m not proposing on doing big jumps at all. Though of course the alternative is for me to spend even more of my money with him :wink:

Was quoted £50 to repair the thread on the crank, so that’s not economic.

On my trials uni, I once went through a few sets of those lightweight Qu-ax cranks in a short time (fortunately they were on sale for $10 with free shipping!), but the problem, I think, was that I had just learned to ride backwards. The only damage was to the pedal threads.

My Nimbus 29 has those same cranks (125mm). I seldom ride it backwards, and I often ride it off curbs or other drops of about 20cm, and am at least 10kg heavier than you, but I have never had a problem with those cranks.

The Nimbus Venture 138mm cranks on my trials uni died recently. The pedal threads were OK, but the cranks had become floppy at the other end (the same amount of floppiness on both cranks, oddly enough). To avoid damaging my hub, I promptly replaced them with some KH Moment 110s that I had picked up during a sale a couple of years ago. I generally say that KH stuff is overrated and over-priced, but these Moments seem quite strong. They also appear to have a much wider point of contact with the hub than the Nimbus cranks. I definitely recommend them if you don’t mind the high price, the high Q-factor and having Kris Holm’s engraved signature on an important part of your unicycle!

Anyway, hope this helps!