Hi,
Are there any differences between Impact Athmos cranks And Nimbus Venture2 cranks?
I dont have good experience with ventures And used Athmos Cranks only for 2 months.
Please help me decide which ones should I buy 
The Ventures are much better. The Athmos cranks are a different grade of aluminium which isn’t as strong, if I remember rightly.
I’d highly recommend Ventures, unless you’re going huge.
I have seen Ventures 5 or 6 times And 3 times were broken (bent etc.) And I’ve never heard about broken Athmos cranks 
(I used them only for a short time) I think that Ventures Are from 7075 T6 aluminium and Athmos cranks Are from 7075 aluminium I dont know differences 
can someone help me?
Aluminum is often heat treated to greatly increase tensile strength, T6 indicates a heat treatment, but I’d actually expect both cranks to be from 7075 T6 aluminum, maybe someone just didn’t write it out.
I don’t know of anyone using the Athmos cranks, so there is not much data out there, which is probably why you never heard of any broken. If you do any drops >30cm, and you don’t have good technique, I would not recommend either of these cranks, get some KH spirits, QX-ZeroQ (the black version) or Mad4one technos. For just long distance or freestyle, both should be fine, as long as you make sure your pedals are installed tight.
hijack
Sorry to hijack this but has anyone used the new aluminium Groovy cranks? How do they stack up against Finn’s list?
Ventures are fine for 5/6 foot drops with correct technique. I know because I ride downhill and freeride on mine with no problems at all. I wouldn’t dream of doing anything close to the same stuff on Athmos cranks.
Groovys are premium cranks, some of the best you can get, so would handle anything you can throw at them. The Ventures and Athmos cranks aren’t even in the same league.
No experience with Impact Athmos, but I had a set of 138mm Nimbus Venture2 cranks that got a bit floppy after a while. The floppiness developed on both sides equally, but it appears not to have damaged my hub. I weigh 90+ kg and do a lot of drops, though usually nothing more than 30cm, and I almost always land with a roll-out unless sidehopping down the stairs one at a time. Other cranks I have used subsequently -old KH Moments and Qu-ax black ZeroQs- seem to have a broader interface with the hub and seem to be stronger.
I assume the “floppiness” comes from the cranks, not from the hub. My guess is: the metal in most hubs is stronger than the attached cranks. I’ve used 165mm Ventures and 170 QuAx cranks on my 26" muni. When the cranks were new, the crank bolts became tight just as the gap started to disappear in the spacers. Now, after much riding, both sets of cranks bottom out without spacers. I’m forced to use spacers, and while I’m happy to now be able to tighten the holy crap out of the crank bolts, there is is a bit of play in the interface (the cranks are tight, side-to-side, but there is play in forward-backward-pedaling direction). I assume, as well, that this doesn’t damage the interface. I need to find a good lubricant for the interface, however, because there’s a lot of creaking with this setup.
This is sort of off-topic…Florian explained to me that the ISIS specification isn’t perfect, particularly because the flare of the interface is only 1%, when it should be more steep. I own one of the latest, 800 series geared hubs. The people who built my wheel (I’m the freak with the g20) and assembled the cranks didn’t use spacers. They may have been confused about the new engineering of the Schlumpf hub, allowing spacers to place external pressure on the hub. Anyhow, I had problems, initially with the cranks loosening. Later on, I found out that spacers can be used, I tightened the heck out of the crank bolts, and nothing has come loose. I assume the same issue, though, with the play in the interface, is happening with my Schlumpf. It’s hard to tell because there is already normal play in the clutch mechanisms of all Schlumpf hubs.
I’ve never bent a pair of cranks. I’m a near 100kg rider, but I do small drops. I have noticed, with the Ventures, that they need regular tightening of the pedals, and with each tightening, the pedals sink a tiny bit further into the cranks, so that over time a slight concavity develops in the cranks where the pedals are screwed in. I assume this is a function of the softer metal. I bought Impact Eiffel cranks for my street uni, I tightened the crank bolts once, and they’ve never needed re-tightening. I assume that’s a function of the harder metal.
I can’t answer the OP’s question, but I have had issues, listed above, with less-than-top-quality cranks. Though I hardly possess the chops to deserve top-shelf cranks, I do get annoyed when anything on my unicycle stops feeling “tight”.
Definetely agree, Ventures are very capable of handling very high drops, if you know how to land. It’s just that most people will do some pretty terrible landings before they figure out how to keep the impact on yor body and components low, which is why I’d personally recommend investing in higher tier cranks, instead of having to buy twice. It depends on your wheelsize and chosen crank length too, I feel like my landings on a 26" are automatically a lot smoother than on my 20", even if I do the same size jump (maybe I should try to find a nice 7 set to test that theory), since it allows you to ride out faster.
Tony, what unicycle and what kind of riding are you doing with these?
I’m also looking for cranks and I hope answers to my questions here might help you out too.
I don’t really like the 137 Spirits that came on my KH20 - the wider Q has never bothered me on bigger wheels but it bothers me on the 20.
I’m thinking along the lines of Finn’s advice when I change them - buy the best and only pay once!
Venture 2 are ruled out because they don’t look great for learning to do stuff stood on the cranks, and I don’t like the sound of any play developing.
The Tecnos look good but work out more expensive than Groovys if I want to try a rollo disc. The Qu-Ax zeroQ look like they’d cost me a lot in shaved shoe rubber!
What’s my best option for the 20?
Cranks are much easier to replace than a hub, so that would make sense.
I’m not sure about that. As soon as I noticed play in my old Nimbus Ventures, I removed them. My hub wasn’t damaged, but I figured that eventually it might be.
A friend of mine rode with his seat backwards for a few miles, and when he brought me his uni, it not only needed new cranks, but a new pedal as well. Normally in this situation, the pedal spindle just chews up the crank and remains as good as new, but in extreme cases, I think the softer metal can eventually damage the harder metal. I was afraid my ageing Nimbus cranks would do that to my hub.
Your story makes me glad I didn’t throw out those old cranks, though. I hadn’t even thought of trying to bolt them on without spacers, as you did, but maybe that would be the way to squeeze some more mileage out of them! The play they have is the same as yours: forward-backward, not side-to-side, but I didn’t have the problem you had of having to tighten the pedals over and over, so the threads are still good. My initial thought was just to keep them around in case I want to make an ultimate wheel one day.
Venture cranks are vastly better than the Impact Athmos cranks.
Although both cranks are made of 7075 aluminium, the quality of that aluminium appears to be dramatically different. The Althmos has a tendency to snap or fail at the pedals - unfortunately this is very common. The Nimbus II cranks have an incredibly good record for bending or breaking (we have never had one snap). Tony Black, if you have several bent Venture 2 cranks can you please forward these on to us as we have no record of these.
The main problem with the venture 2 cranks seams to be at the ISIS interface where there is very little tolerance for wear.
Roger