Nimbus X hub design problems

There seem to be a number of design flaws in the Nimbus "ISIS" hub design used on the Nimbus X, Nimbus II, and various other unicycles from unicycle.com. The spacers used appear to violate ISIS standards, and they cause friction which prevents free rotation of the wheel. The outer face of the custom bearings appear to be made of a relatively soft aluminum which deforms under normal use conditions.

Category:

Howto & Style

Tags:

• unicycle
• engineering
• manufacturing
• criticism

[GShoe32]

you can remove the spacers, my koxx one came with the cranks installed w/o spacers and the spacers came seperately

[tholub]

@GShoe32 The bearing tolerances on the Nimbus aren't tight enough for that to be reliable; some people who've installed them without the spacers find that the bearings move on the axle. And if you care about standards, the spacers are required for the system to be ISIS-compliant (although it's probably not compliant even with the spacers).

Anyway, I don't think they're selling this particular design anymore. It works OK on the 42mm OD bearings without the sleeves.

[TeamInsomnia]

not really a hub design problem. that's not the normal bearing. udc probably gave you that as a way to get rid of the old 40mm bearing frames. jerks

[tholub]

@TeamInsomnia

Yes, you're right, it's not a problem with the hub itself, it's the overall design of the system when jammed into a frame with 40mm bearing holders. UDC agreed to take it back and sent me another one with 42mm bearing holders.

The shimmed bearing required to fit the ISIS hub into a 40mm frame looks like a hokey solution.

[eraserhead6]

It sounds like you have 42mm bearings in a frame designed for a square tapered axle hub with 40mm bearings. Did you buy the parts and assemble them or did you buy the unicycle preassembled?

[unicyclelover17]

do u happen to live in san miguel?