Qu-ax lightweight ISIS cranks for trials

Hi everyone,

Sometime this year (hopefully) I will be building up a new trials uni. I’m going for light but strong. Originally, I was going to get Tensile cranks, however they are very expensive. Moments are heavy for my liking (at 610 grams) as are qu-ax CrMo ISIS (at 510 grams).

So I was looking around and saw the qu-ax aluminum ISIS cranks. Very cheap, very light (at around 380 grams) but it says they are not recommended for big jumping. They are so cheap that I wouldn’t really mind getting a pair and seeing if they will hold up. I am pretty easy on my equipment.

The thing is, if I get the aluminum qu-ax ISIS cranks and they bend, is there a chance that the bending will damage the hub? I have no experience with bent cranks, so I would appreciate it if you guys let me know whether there would be any risk to my hub if the cranks bent.



would seem unlikely, the material your axle is made from is much harder than the crank material.

I have these cranks on my hockey uni, and the ST versions on my 36er, and they are wonderful bits of kit. Might well be worth a shot if you’re not going to go too big or you have good form. Can’t imagine they’d be too good for crank grabs as the edge is heavily rounded off.

yeah at worst the crank will break. I’d be quite up for trying them as well actually, cause they come in loads of sizes so you could easily give different sizes a go. shame they are 145mm, the difference is suprisingly nasty between 140 and 145 on a 19" wheel

you’re axle is crmo so much less likely to break.

Ahh lucky, building a Trials Uni would be sooo much fun! If I were you, this is all the stuff I would buy :slight_smile:

Seatpost Clamp

I think that would be light, yet very strong.

Have fun building it though!


Or these pedals too…


Brendan- I’m used to 150s on my 19":stuck_out_tongue:

Thanks for the info guys.

Issac- that uni sounds ok, except for the cranks, the frame, clamp and the seatpost. Cranks will probably end up being qu-ax lightweight ISIS, a canadianunicycling.com frame if I win the competition or KH if I don’t, and the post will be CrMo because alu will break in a few rides. Plus I will get CF base (Scott Wallis if I can find out if he’s still making bases) and a thompson masterpiece post if I get a SW base. Seatpost clamp will be a WTP Supreme clamp for .2 ounces of weight savings:)

If I wasnt saving up for moab I would go all out and buy something exactly like Danni’s :roll_eyes:

The qu ax cranks are quite weak. I personally wouldn’t get them, even for the price.

If you’re on a budget though, and have nothing to lose (breaking a crank can really hurt) I’d get it.

My seatclamp weighs 8 grams;) .

Personal experience with the qu-ax cranks? Where did you hear that they are weak?

Omni seatclamp right? I bet you have to straighten your seat after every fall:)

Not at all, I was very surprised. You just got to tighten the bolt pretty darn tight.

I’d give them a shot if you’re on a budget, but I think they have less Q-factor than their Cro-mo cranks, so wouldn’t be a perfect comparison.

Where’d you get 150’s? Steel them of a 24" DX?

I’ve heard MG 1’s slide off their spindle relatively easily.

I’d get Kona Wah Wah’s insead. A couple dollars more ($80 retail) and 18 g. heavier (478 g), but they look a lot stonger, have more screws, and no set screws.

For me it’s harder to adjust the position of my feet w/ set screws for a given level of traction, plus I’ve heard they rip out easier.

I ordered the 150’s through a bike shop. They got them directly from Seattle Bike Supply.

The Kona Wah Wahs are about 100 grams heavier than MG-1s.

OK one more question:)

All the other aluminum cranks I’ve seen have CrMo pedal inserts. How will the pedal threads hold up on the qu-ax cranks hold up to CrMo pedal spindles?

I’m actually not sure what kind of inserts they have now. I had a pair from when they first came out and the pedal threads stripped out fairly easy. However, I also have a newer pair that I’ve had absolutely no problems with. But I don’t know what the technical specs are of the threads/inserts.

The pair that stripped out I got the threads re-tapped at a bikeshop for $5.

Sorry, that was misleading. I meant in comparison to the ones Isaac posted.

I’ve heard low profile pedals give a more stable feeling. I can believe this since I have some thick pedals and they have a much less stable feeling than other sets of pedals I have. The downside is in the past because of their design, they eventually slide off the spindle fairly quickly from heavy landings & multiple UPD’s.

Those Kona’s came out after I read that and I don’t know if the pedal is secured to the spindle in the same way.

Thanks for the info Forrest.

Skilewis- Makes sense. The lower your foot is above the axle the less your foot should wobble.