N360 Leaking Issues

[FransS]

There have been a lot of leaking issues with the first versions of the N360, mostly on the drive-side where the freewheel was filled wih traction fluid and often leaked onto the spokes and rims, but also on the left-side.

Although NuVinci claims it is an exception and they replace any leaking hub instantly, my experience with several hub is that they all leak, sometimes only a bit, sometime more, often it is intermittent and it seems related to temperature.

In 2012 NuVinci had made some adaptions to solve this issue and the first experiences were positive.
However, of the four 2012 hubs I have running, one started leaking a little on the left-side a few months ago, I left it as it wasn't dramatic and it still leaks a little, but it's like a "sweating" Rohloff.

Now I have just returned from a biking-trip (on another bike) with the latest version which I got as a replacement for a grinding hub. It was the first trip with this hub and right from the start it leaked seriously on the drive-side. I cleaned the hub/spokes/rim daily to see whether it would stop, and so it did after a week and I continued cycling for another two weeks (about 1700 km in total).
I neither feel nor hear anything disturbing.
I have no idea how much fluid has been lost, it is quite a lot but 80 ml is almost a complete chain-oil bottle and that seems a lot more.

I'm going to report this to NuVinci but I am getting fed-up with re-lacing new hubs, so I want to have some more quarantee that they have come to grips with the issue.

[Normand_Nadon]

400km on mine and no leak for the moment... you are really unlucky!

Time will tell if I am going to face the same issue.

[Oran]

I’ve currently done 2300miles (3700km) and my 2012 hub hasn’t lost a drop of traction fluid. I thought the problem had been fixed but it seems not.

Having seen the patents I wonder if there will be a new model of the hub sometime soon with more significant modifications made. The evidence suggests there is something fundamentally wrong with the design of the N360. Or maybe you have just been very unlucky. Without the old forum it is difficult to judge how many other hubs are leaking, even then I didn’t know how much Fallbrook controlled what we saw.

We should spread the word about this section of the forum so it can become the top place to discuss NuVinci hubs.

[Oran]

I forgot about it but a few months ago I tried to fix one of the leaking hubs I have. I had reopened the hub and while having a close look at the leaking seal I discovered a garter spring hidden within it. This means the seal can be tightened by simply shortening the spring. The spring is joined by having one end reduced in diameter so that it screws into the other. Tightening a seal in theory makes it able to tolerate larger imperfections.

The hub is installed on a bicycle that I keep at a relative’s house, I only use it when I go to visit. During my stay I did 188 miles and shortened the garter spring three times which reduced its circumference from 86mm to 74mm. Unfortunately I was unable to stop the leak. It seems there is something else going on.

Possible explanations for the leak now are that the seal is made of the wrong rubber. The seal is not aligned with the shaft or the metal particles are interfering as I said they were.

The only way I see of fixing it now is to experiment with new seals which will get a bit complicated as there are many different types and materials. If the shaft is misaligned or has imperfections I don’t think there is much I can do.

[Normand_Nadon]

Try some seals made out of high duty industrial material (ie. vitton) and that are arsh condition specific... should cost around 5-10$ a seal!!!

Thanks for your input (and for the other thread on the planetary thing)

[FransS]

I have reported the issue to NuVinci, and they offered a replacement as usual, but this time I insisted in an investigation and now my wheel is waiting to be collected for investigation in the European Service Centre.
Hopefully I will get some info. To be continued.

[Normand_Nadon]

And then two men dressed in black with sunglasses knock at your door and you wake-up not knowing what happened!

[Oran]

Let’s hope not I want to know what FransS finds out.

I’ll consider Viton if I decide to investigate replacement seals again. I gave up when I began to learn that the operation of a seal is far more complicated than I had first thought. Things such as micro structures in the contact area of the sealing lip to enable a certain amount of pump back. And not too much or the seal will run dry and wear out or squeak. There are so many different designs I would need to consult a seal expert if I’m to have any chance of finding the right one.

[Normand_Nadon]

Seals are not built by Fallbrook! They are from well known companies such as SKF, NSK etc... Just check for the number on the current seal and you will easily find replacements in any brand... some numbers/letters are just refering to tolerance or material.

Show me the seal we are talking about and I can help you with that (where it goes - casing and what it seals - dimmension and number if you have it)

[Oran]

That’s a very good point you make about Fallbrook not making the seals, I hadn’t really thought of it like that. I can certainly look for a number and find out more about it. However that will be the seal I don’t want as it has proved not to work. The question is which seal to upgrade it to.