review of nimbus X cranks

[markf]

bought these a while ago(6 months-ish) and they just now crapped out on me. I have the 152mm on a 24" Muni. I ride street and off-road with it and do stairs and 3-4 foot drops and such. Cranks held up pretty well until recently when the left one fell off a couple times and is now unrideable. If you ride hard/big drops, it'd probably be worth the cash to get some better cranks. If you're a beginner and want some good cranks to freestyle/learn with these are very nice.

Final verdict: if you ride hard at all, spend the money, its worth it in the long run.

ps. i'm 6'4 and weigh ~180 lbs. If you're significantly lighter you should probably be able to not kill these cranks like i did.

[One on one]

Why did the crank fall off? Had the bolt gotten loose that holds the crank on and you hadn't noticed it. If that's the case, you really can't blame the cranks for that.

[markf]

well the first time it came off just because it came a little loose. i tightened them both occasionally. i simply rounded off the inside part of the crank that attaches to the hub. it sucked.

[john_childs]

That is a problem with aluminum cranks. Any aluminum crank. If the crank gets loose, and you ride while it is loose, you will round out the taper on the crank. The crank will be ruined.

Aluminum is softer than steel. If the crank gets loose the tapers on the crank are going to be ruined long before the hub suffers any damage.

If you have aluminum cranks you need to make sure that the cranks are installed tight. And you need to make sure that they never ever come loose. It only takes once for the cranks to be ruined. It doesn't matter whether they're Nimbus cranks or Kooka cranks. If they're aluminum they're vulnerable.

If you're going to use aluminum cranks you really should get a torque wrench so you can make sure they are installed tight. Saving one set of cranks will pay for the torque wrench.

The proper way to install cranks:
1) Put a little bit of grease on the tapers
2) Slide the crank onto the hub
3) Put a few drops of Red Loctite threadlocker on the nut/bolt
4) Thread on the nut/bolt
5) Use a torque wrench to tighten the nut/bolt to 40 foot-pounds.
6) Let the Loctite cure for 6 hours or so

I have never had a crank come loose that has been installed using a torque wrench according to those steps. That includes the aluminum Black Widow Euro cranks that I have on my Coker.

[jagur]

good review and great info so far.

my 127mm Nimbus X cranks have stayed right 'N tight for about 3 months now. they are matched to a UDC hub, I both torqued them on and greased the tapers.

[markf]

john childs--

i did all that save the locktite. damn that probably would've helped. maybe even saved them. also cranks will loosen a bit with large drops and whatnot, so if you have these you should check them occasionally. but my next set of cranks is gonna be something splined.

[john_childs]

Most aluminum cranks don't do well with a lot of jumping. An exception is the Kooka cranks which seem to stay tight even with harder riding.

All aluminum alloy is not created equal. All manufacturing methods are not created equal. There are different grades of aluminum alloy and different methods for manufacturing.

The less expensive aluminum alloy used in lower cost cranks is generally softer and less stiff than the more expensive aluminum alloy used in the higher end cranks like Kooka. Stronger material generally means a stronger crank.

Manufacturing methods also play a role in how strong the crank will be. Some cranks are machined directly from a block of aluminum. The amount of cold working of the aluminum alloy before machining will also play a role. Another way of making a crank is to forge it. Forging squishes the metal into the shape of a the crank. It gets the grains in the metal to line up which makes the crank stronger. The aluminum cranks from companies like Race Face are forged.

The general rule of thumb is that lower cost aluminum cranks aren't going to hold up to jumping. The more expensive aluminum cranks that are made from stronger alloy and manufactured with better manufacturing methods will hold up better.

I don't know what alloy the Nimbus cranks are made from and I don't know how they're machined. Judging by the price it's probably one of the softer alloys, but I could be wrong.

[markf]

they came recommended from some other people as being pretty good, especially for the relatively low price. i'm not sure what i was expecting from them, but i hoped they'd last longer than they did. the next set i get i think will be splined. now to debate the merits of kh2005 vs profile.

[brockfisher05]

or he has the cranks on the wrong sides

[markf]

totally not on the wrong sides. i'm not quite that dumb. and upon re-examination of both hub and crank, i found that the hub was also slightly damaged. now its a chicken or egg thing figuring out which piece broke the other. also my roommate has a pair of these on his brand new uni and other than occasional loosening they work great for him.

[Krashin'Kenny]

I've had a pair of 150 mm Nimbus X cranks on my Muni for about 3 months and they've held up quite well. I have a habit of checking the tightness of my crank bolts before each ride, and they have never came loose My only complaint is that ocassionally, I catch my heel on the sharp edge of the crank near the axle and get a UPD