A funny thing happened on the way to work the other day. Early in the morning, I was riding to a clients office on the other side of town. It was below freezing and I was a few blocks from my house when I realized I could not shift. . I was midrange in the Nuvinci ratios, so I continued, thinking I would stop at a well lit parking lot and examine the cables and shift interface. I did and found nothing stuck or adhering to the link and continued along on my exotically geared single speed. After a couple of hours and a breakfast meeting, I went back out, the temperature had climbed to around 45 degrees by then, and I found the shifter working just as it should with no problem. The only thing I could imagine was that the shift interface had gotten moisture into it and frozen during the night.
The shift interface is that little plastic module I had had a problem with before. I decided to take a closer look at this widget and set the hub in hyperdrive (high gear), removed the retaining nut and disassembled it to soak it in degreaser. Inside this pesky rascal is a fairly straight forward collection of 8 little gears to regulate the stress of turning the hub mechanism.
The outer parts of the casing simply snap together and all the parts are of nylon plastic material. I am guessing that water got into the unit during one of the recent rain storms. I have felt the original lube used was a little thin, and waterproofing on the unit was not good because I have found an oily film develop on the hub and spokes over time.
After soaking the parts overnight, drying them and leaving them to air dry, I decided to use a thin film of Phil Wood waterproof grease, after all, the worst that could happen is that I might have to do it again.
After lubing the little pieces, I reassembled the parts
and snapped the unit back together.
Mounting the unit back onto the wheel is rather simple.
The interface has to be set into hyperdrive and one can simply estimate a level
position compared to the dropout angle.
Once put back in place with the retaining nut, the wheel can be reinstalled and the cables just click into place.
I was surprised the unit didn't shift a little more slowly with the Phil grease. It's a much thicker lube than the factory used, but the unit shifts just fine and I haven't seen any indication of a seepage or leaking that I saw with the original oil. If this is the only problem I have with the Nuvinci drivetrain, it will be a vast improvement over the Shimano Nexus I have also used.
hi there, i was just research more about the NuVinci hubs, and came across your site, nicely done!
ReplyDeletehave you been out on days when it's 20F or lower for more than 30mins? or at least left the bike/hub outside in such conditions and found it hard to shift? i wondered if it's the hub itself or the cables/housing. i've had similar frozen problems with brakes, water got into the housing and couldn't brake the rear wheel.
let me know if you have troubleshot the NuVinci further, thanks!!
The shift interface unit is not a watertight unit. I've had problems with it freezing when the temperature drops after having ridden on rainy days. Now we've recently had consistently cold weather without rain and I have had no problems again...so.far.
ReplyDeleteMarc
I came across this and wanted to add, in some N360 installations the cables can also be a problem. In the Organic Transit ELF, owners have reported the same freezing up behavior as noted above. In some cases the problem was freezing water collecting in the long run cables to the rear hub from the front control. The cables as installed at the factory pointed down from the rear hub, then had a gradual turn upward before hitting a support strap. Quick solution was to put the front wheels of the ELF on a set of empty paint buckets when warmer to allow water to drip out. Longer term solution is to lube the cable and reset the hub and cable to eliminate the low spot where water collected.
ReplyDeleteYou may have something here. I put some heat (space heater) near the bottom bracket where the cable housing loop below it. The shifting eased within minutes. It may have been moisture in the housing after all. I will pursue this after I think about an easy solution.
DeleteI can see the point, but I haven't seen that happen with similar installations like Shimano IGH which also have full length housings where moisture could collect. I notice that the Nuvinci Shift interface is freezing again this winter, it works above 20F but will freeze below that. When heat, from a space heater is applied, it thaws,but that heat shouldn't be affecting the cable housing at all. It is food for thought. I may take it all apart, install new cables, lube everything again and see what happens.
ReplyDeleteIf you are looking at this because of the freezing point, take a look at this new post. I found a cable housing was split and collecting water causing the issues.
ReplyDeletehttp://simplecycle-marc.blogspot.com/2014/01/misleading-temperatures.html