inside the nuvinci hub
- Thread starter camlifter
- Start date
camlifter
Active Member
thanks barely. the parts in the 3rd pic are one of the sprag units, you can see that every other slot is empty. i'm working on cutting some rollers to fit in those slots, then i'm going to add a .020 shim and put it back together, if it works i'm going to take it back apart and swap the sprags and see if it will work backwards.
I don't have a Morini, so I didn't see this thread until now. I am running a Nu Vinci, so naturally I am curious. If you can't get the fluid from Nu Vinci, try this. I used to have an old Clipper concrete saw with the VG4D Wisconsin engine. It ran a CVT type transmission for the traction drive using a cone and ring type of setup that used the same theory of power transmission. The fluid was also manufactured by Valvoline and was called traction fluid. I remember ordering a quart from them years ago......expensive at the time. Might be the same stuff.
Denny
Denny
Goat Herder
Gutter Rider
Goat Herder
Gutter Rider
I suspect this may be related ,but I am not making any assumptions.
Changing your transfer case fluid|GM-Trucks.com
Reason being its the same color
Changing your transfer case fluid|GM-Trucks.com
Reason being its the same color
Hey folks,
Came across this thread and thought I'd offer a few inside tips:
1. Do NOT try replacing the fluid with anything other than Valvoline Invaritorc 638. NuVinci customer service should be able to hook you up. It truly is a special fluid. Almost everything else will slip.
2. Without better pics of your parts, I can't tell for sure but it is very, very likely that the failure you experienced was the freewheel, not the trans internals or the fluid. When the fluid is failed, it looks like gray jello, and it takes quite a lot to fail it. In fact, it will never fail under even the most extreme human powered bike use that it was intended for. When this happens, there are usually accompanying severe score marks on the rings, balls and/or central idler. I don't see any of that in your pics, in fact, the traction surfaces look great.
3. The other possible failure point are the tabs on the input driver. I didn't look at your engine specs, but I would guess that the power is well beyond what the bicycle design levels were and the spikes from combustion events can pound those little tabs right off. Some sort of torsional isolator, like a rubber coupling, would do wonders for life if this is the issue.
4. One last possible issue would be that the cover was already coming unscrewed. This is the least likely possibility and usually only happens under high, repeated, REVERSE braking loads. The cover torque spec is ~300 N-m, and Loc-tite is used on it.
5. You don't want to add any shims to the unit. This will just make it hard to shift. If there is enough wear to require more shimming, it would be very, very visible on the balls and rings.
With respect to the missing cam rollers, that would mark this unit as a bike production hub. The hub that comes in the NuVinci Developer's Kit has a full complement of rollers, along with some other tweaks, to make it more durable in high power apps like yours. The Developers Kit also has a programmable automatic shifter that you can set up to hold either your engine or your pedals at a constant rpm.
Hope this was helpful!
Came across this thread and thought I'd offer a few inside tips:
1. Do NOT try replacing the fluid with anything other than Valvoline Invaritorc 638. NuVinci customer service should be able to hook you up. It truly is a special fluid. Almost everything else will slip.
2. Without better pics of your parts, I can't tell for sure but it is very, very likely that the failure you experienced was the freewheel, not the trans internals or the fluid. When the fluid is failed, it looks like gray jello, and it takes quite a lot to fail it. In fact, it will never fail under even the most extreme human powered bike use that it was intended for. When this happens, there are usually accompanying severe score marks on the rings, balls and/or central idler. I don't see any of that in your pics, in fact, the traction surfaces look great.
3. The other possible failure point are the tabs on the input driver. I didn't look at your engine specs, but I would guess that the power is well beyond what the bicycle design levels were and the spikes from combustion events can pound those little tabs right off. Some sort of torsional isolator, like a rubber coupling, would do wonders for life if this is the issue.
4. One last possible issue would be that the cover was already coming unscrewed. This is the least likely possibility and usually only happens under high, repeated, REVERSE braking loads. The cover torque spec is ~300 N-m, and Loc-tite is used on it.
5. You don't want to add any shims to the unit. This will just make it hard to shift. If there is enough wear to require more shimming, it would be very, very visible on the balls and rings.
With respect to the missing cam rollers, that would mark this unit as a bike production hub. The hub that comes in the NuVinci Developer's Kit has a full complement of rollers, along with some other tweaks, to make it more durable in high power apps like yours. The Developers Kit also has a programmable automatic shifter that you can set up to hold either your engine or your pedals at a constant rpm.
Hope this was helpful!
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camlifter
Active Member
great info, thanks for your input. the hub came from a cadillac bike that i bought. there seems to be no wear at all in the hub, the freewheel is working, but it's so tight i wasn't able to get it off, actually broke the tool i bought for it trying to get it off.
i'm determined to get this hub to hold up to a motor bike so i'm open to experimenting. i'm all most positive the noise it was making was the sprag rollers jumping over the wedge ramps in the sprag, the cover was very tight, had to use a heat gun on the lock tight to get it off, the fluid is a light green color now after setting in an open container for awhile, it was a bright blue when i drained it out.
i'm determined to get this hub to hold up to a motor bike so i'm open to experimenting. i'm all most positive the noise it was making was the sprag rollers jumping over the wedge ramps in the sprag, the cover was very tight, had to use a heat gun on the lock tight to get it off, the fluid is a light green color now after setting in an open container for awhile, it was a bright blue when i drained it out.
Vinci
Thanks for the info, and the response. I've only been running my hub for a couple months, but absolutely love it.
I was having trouble finding a controller until Mr Dave Staton gave me your number. After I knew who to call, the service was great. Had a controller and the extra long cables in less than a week......and this is in Alaska!!!! Anyway, so far my hub is doing fine with a 49cc 4 stroke, but it is nice to know that you back up your product. Thanks again
Denny
Thanks for the info, and the response. I've only been running my hub for a couple months, but absolutely love it.
I was having trouble finding a controller until Mr Dave Staton gave me your number. After I knew who to call, the service was great. Had a controller and the extra long cables in less than a week......and this is in Alaska!!!! Anyway, so far my hub is doing fine with a 49cc 4 stroke, but it is nice to know that you back up your product. Thanks again
Denny
If the rollers were jumping the cam, the torsional spring that wraps around the ring inside the sheet metal part that holds the rollers should show some evidence of this - basically, it would be a mess! Were those wire springs still intact with one end in the slot on the sheet metal part and the other end stuck in a hole in the ring when you disassembled it?
camlifter
Active Member
they were still inside the sprag drum, but only one end was in the slot, one end has a larger hook on the end the other end has a very small hook on it. i could see inside the sprag drum where the small hook had been spinning around in there , there were tiny scratch marks in side it. are the hooks of the wire spring the same size because mine are smaller on one end, but there were no broken pieces laying inside the hub.
sounds like your saying the wire spring winds up inside the drum to keep the sprag tight. i was thinking the sprag wedged on it's rollers and ramps and the spring was just to release tension for ease of shifting.
this is the kind of info we need, really appreciate you vinci for helping. were all going to be more than willing to be guinea pigs for making the most of the nuvinci hub. we've been searching for a long time for a hub we can make hold up to a motor bike.
sounds like your saying the wire spring winds up inside the drum to keep the sprag tight. i was thinking the sprag wedged on it's rollers and ramps and the spring was just to release tension for ease of shifting.
this is the kind of info we need, really appreciate you vinci for helping. were all going to be more than willing to be guinea pigs for making the most of the nuvinci hub. we've been searching for a long time for a hub we can make hold up to a motor bike.
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pdubs
New Member
can't really tell from the pics.. but does the non drive side have some sort of seal??
evertime i park my bike after a ride it seeps oil. after it cools down it stops.
this getting annoying and i don't want to end up slipping under load miles from home.
Looks like i'll have to call our Valvoline rep for some fluid as well.. can't seem to find it sold on the net?
Maybe my NAPA can order a quart.
evertime i park my bike after a ride it seeps oil. after it cools down it stops.
this getting annoying and i don't want to end up slipping under load miles from home.
Looks like i'll have to call our Valvoline rep for some fluid as well.. can't seem to find it sold on the net?
Maybe my NAPA can order a quart.
If there are signs that the spring was spinning this may indeed be the cause of your problems. What the spring does is apply a very light preload to start the cam rollers up their ramps. Without this preload, the flat side of the sprag will just roll right over the rollers and no torque is transferred. Check with the NuVinci customer service line - if there are any of those left in the parts stock, they may be able to send you new preload springs. This model of hub is out of production now, and parts are limited.
If the spring end is has been shortened on yours by wear, you'll have the issue again if you just reassemble with the old spring. You may be able to bend the sheetmetal in ever so slightly inward around the spring slot so that even the shorter spring end will not come out of it, BUT, you have to watch that you still leave clearance between the cam roller retainer and the ring that is inside it. Interference will also keep the cam roller from doing its job, and even reducing the clearance too much can cause problems when the hub is allowed to soak at temps below freezing.
Yes, there is a seal, but it would be very hard to replace. If you are running the hub with sustained high power, the fluid is looking for a place to expand and that seal is probably the weak point. As I said in an earlier post, this version was never designed to run with more than human power! Having said that, you're probably not loosing nearly as much as it appears unless there is an actual puddle.
Don't waste your time with NAPA or Valvoline - you'll get a lot of shrugs and guesses. Valvoline field reps have never encountered Invaritorc for the most part. Just call the NuVinci customer service line on the Fallbrook website and ask to buy a refill bottle.
Glad you like it Denny! While all motorized apps are beyond design (and thus warranty) spec for this hub, it doesn't stop us from appreciating what folks like you are doing.
Goat Herder
Gutter Rider
Vinci is N.V. gonna make a hub in the future for our motor bikes? Thanks again for getting in touch with us! Your knowledge and incite is very valuable to us!!
I see the developers kit now. Wish I would have knew more and bought that
Well not so much for the shifter but stronger guts
Fallbrook Technologies
How about getting this thing left side drive? A good design would be to shave weight , do away with the power robbing J Shafts and gear box's. Well for or tiny motors.. anyway!
Since getting my clutch to behave this hub has been very nice lately!
I see the developers kit now. Wish I would have knew more and bought that
Well not so much for the shifter but stronger gutsFallbrook Technologies
How about getting this thing left side drive? A good design would be to shave weight , do away with the power robbing J Shafts and gear box's. Well for or tiny motors.. anyway!
Since getting my clutch to behave this hub has been very nice lately!
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pdubs
New Member
well that answers my question very well.. endless searches on the net fail to find an exploded view of this hub.
it is leaking that bad.. all over the wheel, and puddles after i park it..
guess ill clean it up and seal it and refill the hub.
Goat Herder
Gutter Rider
I do understand the warranty thing. I did design my drive train so the hub should never *see* more than about 80 ft lb of torque, but your comment about *spikes* got me thinking. I don't have room for an isolator unless I use a belt in the primary reduction. I wanted to do that anyway, so you've given me another reason to machine up some special sheaves. ; )
Denny
BarelyAWake
New Member
Heck of a proving ground eh?
I just wanted to thank ya for your participation & interest Vinci, good ta have ya here w/o a doubt
