N360 Leaking Issues

[Normand_Nadon]

What do you mean by "installed the wrong way" ??? An oil seal can only be installed on one way!

[Oran]

I mean flipped over and installed with the oil side on the air side. I thought seals typically had the numbered side facing out and the garter spring accessible from the oil side. I found the seal in the 2012 hub installed the other way round.

[Normand_Nadon]

That is really weird! Somebody does not know how to use seals at NuVinci... no wonder they have leaking issues!
They probably never heard of metal hardness neither... hence the issues of the ball pivots grinding their raceways!

[Oran]

No what’s weird is that installing the seal the wrong way round actually fixed the leak.

I‘m not sure that it’s a metal hardness issue but instead I think it’s a flaw with the design. For a ball on an axle to be able to pivot on its centre when guided by slots at each end and do so without friction, the ends of the axle must rotate in opposite directions. Whichever end has the highest load will dictate the direction of rotation. As the ball and axle can’t all move in one direction the other end of the axle must skid creating unavoidable ware. The only way to fix it is to isolate the two ends of the axle by putting a bearing on one end.

It’s also possible that this fiction is necessary for the functioning of the shifting mechanism. It may be that it holds the axles and avoids the need for a large resistance in the shifter to prevent auto shifting. Adding friction to the shifter would put extra strain on the cables.

I feel there’s a reason their doing it this way probably because fixing it will require a much more complicated mechanism.

What I think Fallbrook has done is design these hubs so that they are simple and cheap to manufacture. This enables them to test the market and find out if people really what CVTs on their bicycles. They were minimising the cost of R & D and specialist machinery for manufacture. I think the patents show the next generation of hub which their probably working on now.

[FransS]

Hi Oran,
I'm not so pessimistic about the lifetime of the hubs because a friend of mine uses it for serious commuting and he must have done well in excess of the 3000 miles.
Also I have installed a leaking hub which was not reclaimed on my daily bike to see what happens: It stopped leaking and is still running flawlessly after a couple of years.

[Normand_Nadon]

Good to know!

[Oran]

Hi Frans,
That’s interesting that you hub stopped leaking, perhaps I should leave my hubs alone and see if they also stop.

The speed that a hub wears-out probably has a lot to do with the riding style of the person who uses it. Shifting under load is almost certain to be what’s wearing the guide slots. I tend to be shifting continually when I’m riding and my hand rarely leaves the shifter. If it does I soon feel I’m in the wrong ratio. I also have a habit of accelerating hard because that’s one of the things I like about a CVT. This is hard on the hub because it’s shifting under a reasonably high load and against the way the hub what’s to shift.

It looks like a replacement hub is on the way so it doesn’t really matter how long the life is. It will have cost me £20 postage and a couple of hours work dismantling and rebuilding the wheel.

[Oran]

I’ve been able to ride my other bike with a NuVinci hub this holiday. Another 220 miles later making a total of 300 miles, I can safely say it’s still leaking. So far replacing seals on two different hubs has had no noticeable effect on the amount fluid leaking.

I have removed the video from this post because I have chosen to support Fallbrook. It is important to understand that Fallbrook are at the difficult development stage of an exciting new technology in the bicycle world. If this means restricting information provided to the general public and protecting their design from competition, then it had to be done.

I can assure you that customer satisfaction is at the heart of what Fallbrook does. Without the support of customers they could not do what they are doing.

If you have a problem with a hub Fallbrook will be happy to replace it for you, let them worry about what went wrong.

[Normand_Nadon]

Man... it really is a pain in the $/%$%? .

Fallbrook has made mistakes and I hate the way they handle those mistakes.. If my hub ever drips a single drop of oil, I exchanging it for a new one, reselling it and buying a Rohloff !