Pinion Gearbox on a Carver
I just came across this link to Carver, builder of the O'Beast.
It's not on a fatbike yet, but if they can put it into production, I'm sure it'll be an option on the custom Ti O'beast.
Carver Bikes Innovation for 2013 and beyond ...
I would love to have a Pinion unit.
That said, let's say it's an option on the Ti O'beast... the chain line is 54mm on the P1.18, so you're kind of screwed on anything beyond Fat Lite (3.8" casing, 65mm rims).
Hate to be Drew Downer, I do it too well...
I know you don't give up easily so I'm waiting for the worlds first bamboo fatbike with an offset Pinion gearbox.
Originally Posted by Drew Diller
As little bike as possible, as silent as possible.
Latitude: 57º36' Highlands, Scotland
Sandman was testing a Pinion-gearbox bike at one point. I haven't heard what became of that project. Can't remember if it had an extra wide crank axle or if it was the standard unit.
Maybe someone can make a wider gearbox, and use the extra width to allow more gears, and a wider range.
I would think 54mm could clear a tire up to 100mm in total width and keeping a perfectly straight chain, leaving 4mm of clearance. That should cover all of the 3.8-4.0 tires on 82mm rims, except maybe a Nate, which would still have 2.5mm clearance.
oops, I forgot the width of the chain. I think a single speed chain is about 1/4" wide, so half of that would be 1/8" or 3.2mm, so there went my 4mm of clearance.
well, it should still clear a Larry, HuDu, or Floater on RD, and a Nate on a Marge lite.
with a 98mm tire, and a 6.4mm wide chain, you only get 1,8mm of clearance, a few more mm with some of the tires, but still not really enough, so it would need a little tweaking.
I don't think the custom O'Beast accepts any tires over 4.0 anyways, since it is based on the '11 model.
Ah, I think I found an easy solution.
the output on some P1.18 gearboxes has a 4 bolt spider for a belt drive. If you put a chain ring on that with spacers, it should accommodate wider chainlines. You can easily line up the rear sprocket if using a SS cassette hub in the rear, and the crank arms have straight splines and clamp on, so they could be adjusted out if necessary too. there appears to be plenty of room between the sprocket and the crank arm though, probably enough to line up with a 170mm hub.
Has anyone independent assessed the internal losses of a Pinion gearbox vs. a derailleur and common IGHs?
I tried a Hammerschmidt when they first came out and was disappointed by how much drag there was in the overdrive setting. It was bad enough I stopped using the high range and eventually sold the HS since it was just a very expensive/heavy singlering setup for me.
I haven't seen a report on the efficiency yet, but it is supposed to be better than an IGH, but of course, it can never be as efficient as a derailleur, which is just 2 rollers.
the IGHs and the crank over/under drive setups will have more friction from the planetary gear drives having more friction points. The sequential gearbox should have less friction points that the planetary setups.
If it has less drag than a Rohloff/Alfine say I'd be happy. My unscientific testing tells me that any efficiency advantage a derailleur drivetrain has evaporates when the bike is covered in sand/mud/etc...the shifting ability can evaporate as well.
The centralized weight placement of the Pinion makes me happy.
Hopefully some folks in this forum get one and let us know what they think.
My early adopter budget is blown for this year.
Wow, you come up with all the cool old stuff. I like how they integrated frame lugs into the case on that one. I guess that's not as practical now, since everything is aluminum or carbon fiber. You could still use bonded lugs though. Maybe a kit to make your own frame, with tubes you can cut to the desired length, and bond to the lugged joints, and gearbox to make a custom fit frame at home.
Originally Posted by Velobike
Here's one brief report on here:
Originally Posted by vikb
Pinion Gearbox first batch gear skipping issues
ans a ride report for a 29er fully with the p1.18:
Mi:Tech Epsilon Pinion Gear Box FS 29"er: Mid-Term I
Last edited by autodoctor911; 05-05-2013 at 09:15 AM.
636% gear ratio? Yes.
Even gear steps? Yes.
Cheap ss chain? Yes.
5 Lbs? Hmm. I'd say no but how much does a rear cassette, longer chain, bottom bracket, and 2 derailleurs weigh?
Less parts to replace every year? Yes.
Low centrally mounted non moving mass? Yes.
Symmetrical build ss rear hub? Yes.
I, for the most part, dig these. The pedaling efficiency in each gear is definitely something that I'd like to see though.
+1 - I'd also want to see:
Originally Posted by EPcycles
- long term durability/reliability/service life?
- maintenance intervals?
- is it user serviceable?
I just replaced the oil seals in one of my Rohloffs and although it wasn't trivial it was not overly hard. So far I've been able to do all my Rohloff maintenance at home which makes me happy.
I also have confidence in my Rohloffs as their reliability/service life are a reasonably known quantity.
I think long term durability is not yet tested for consumer use, but they definitely simulated some long hard use in the test lab.
Just by looking at the pictures, and the materials used, this thing is way overbuilt. I think they are offering a 40,000 mile warranty as well.
Personally, I'd rather see it be a little less overbuilt, and with fewer gears at wider intervals.
I think the only reason we like the cassette gears as close in ratio as they are is because shifting is harder on bigger jumps, not because we need to be able to fine tune our speed and pedal cadence that much.
I think with the Pinion gearbox I would end up shifting several gears at a time every time I shifted. I think even for the wide 636% range which is more than any 3x10 I've ridden, I would be happy with 10-12 ratios.
the closer the ratios, the more you have to shift. I don't think our pedaling efficiency has that narrow of a rpm powerband to need it.
I don't think anyone will use that range either, unless you're riding mountain roads, and crawling slowly near the top of the hills and going all out downhill.
I would actually prefer a narrower range, close to a 2x10, if it were lighter.
I don't think anyone has done such a test.
Originally Posted by vikb
I agree on your assessment of the HS. Interesting unit, but when even my tolerant self got fed up with the efficiency penalty... damn.
For what it's worth, I have a similarly constructed Metropolis Patterson crank on a city bike, and it's much better. And a similarly constructed Schlumpf crankset boasts high efficiency (haven't looked there in a while).
I'm wondering if the HS has poorly cut and mated gear teeth. Armchair engineer me says such cogs need to be high precision / very high polish to avoid teeth sliding against each other on contact. Not cheap. Maybe the HS... has a high profit margin, to put it nicely.
It has been taking me a long time to come up with any fruits of my labor, but a wide-chainline crashbox very much based off the discontinued G-boxx 2 design is a goal I think about. The interesting tidbit I found from a German tech brief was that the efficiency of well lubricated constantly turning parallel chains is very low.
I suspect they abandoned the design because, in order to get sufficient range to act as a cross country rig, you'd need two really large sprockets on both clusters (at opposite ends), and that would for the need for long chainstays, which is unattractive to enough people, and it would look portly.
I don't give a sh!t about how it looks, I just want it to work. But that isn't a widely marketable opinion.
I think the German engineers doing this gearbox are from an automotive background, and used to making stuff overbuilt for long service life. Here is what they have to say:
"The Pinion gear P1.18 has completed all the practical tests, material tests and operational simulations to ensure maximum quality, reliability and service life. To ensure durability and performance at the highest level, we used real athletes to discover real-world peak forces. Once we knew this data we were able simulate the effects of many years of use under realistic conditions in a short time. Using automotive industry techniques and standards we have tested the complete gearbox, and each individual component, under repetitive use at extreme load. So when you take a new Pinion gearbox bike on the trails we can assure you that you will not be a guinea pig but will be using a product you can rely on."
Test Lab | PINION / P1.18 / DRIVE TECHNOLOGY
I once found a site where an individual had posted efficiency test figures for various IGHs.
I can't seem to find it now, but I remember the rholoff was quite a bit better than the others, and the Nuvinci N360 was quite poor.
I'm happy to be optimistic about it, but until we hear from real riders who are using the Pinion we won't know what's what.
The Hammerschmidt marketing spew was very positive and backed up by great videos with Greg Herbold. The actual product was a dud IMO.
Nobody is going to market their product by saying "Ya the drag kinda sucks, but we haven't figured out how to get rid of it and who knows how long it will last - hopefully long enough for us to make some $$$!"
At least with a Rohloff or a HS if you try it and don't like it you can sell that item and move to a different crank/wheel. With the Pinion you are locked into a very specialized frame which won't be easy to sell - especially if people aren't stoked once they are out in the wild.
So hurry up people get some custom fatty Pinions rolling so we can see how they work....hahahaha....
I agree, let someone else be the guinee pig. I think if the efficiency was that good, they would probably be putting that on their site.
when I first heard about the Nuvinci, I tried to ask them what the efficiency was, and of course they wouldn't give me a straight answer, and kept saying how it will increase efficiency by optimizing the pedal cadence. I think pedaling efficiency is not going to improve at all by having infinite ratios compared to a decent number of fixed ones. You have to be pedaling very slow or very fast to be losing much.
Hopefully someone will test it for the P1.18 and post it online at some point. I don't think I'd get one without knowing, or at least feeling it for myself.
If the gear teeth are precisely matched enough, the friction should be low enough to beat the efficiency of the Rholoff.
Last edited by autodoctor911; 05-05-2013 at 11:43 AM.
I think you mean the efficiency for the parallel chains is very high, as in the friction is low.
Originally Posted by Drew Diller
Is this what you are saying?
Did you find a G-boxx 2 for cheap somehow?
I think the Pinion is replacing it because it is a lot cheaper, as well as possibly performing better in some ways.
Yes. Sorry I'm not always the most clear person...
Originally Posted by autodoctor911
Have you ever worked on a *really* clean single speed drive train, with a clean, but broken in bottom bracket?
Give one crank a strong push, and they'll back pedal a long time.
I think the chain driven G-boxx 2 design is an interesting mix of the complex and the simple. The simple is a known quantity: clean single speed drive trains. The complex is that those are stuffed into a box and each freewheel pawl selectively engaged.
I imagine such a design would be more tolerant of grime than a high polished mated gears design, and could be rebuilt or maintained with relative ease.
But again, the size of the cogs that'd be necessary... it wouldn't win an award for elegance in design.
I know it's really hard to improve on the venerated design of a bicycle, but I think drivetrains are one of the last areas where it is possible. I have encountered so much resistance to the idea, and the curren examples have serious drawbacks (Alfine 8: narrow gear range, awkward down shifting - NuVinci: narrow gear range, poor efficiency, heavy - Rohloff: expensive as hell), which only reinforces that resistance.
The major limiting factor I've encountered with a Gboxx 2 derivative is the very large amount of cable pull that would be required of a shifter (at least 70mm). I own a low cost FDM 3D printer which will be key in solving that problem. The major problem I've had with it so far is that ABS plastic (Lego plastic) has a very high thermal expansion rate, and making precise parts as originally drawn is very difficult, as the plastic will shrink both during and after printing, which will cause overall shrinking, lengthwise warping, or both. I've encountered an alternative "doped" ABS plastic that claims to not have the same warp problems, but haven't tested it yet...
Anyway, I have to put up or shut up on that goal.
70mm total, or for each gear?
single pull cable, or double/pull-pull
or single heavy push/pull?
Total, straight pull through a shaft. EDIT single pull, spring opposed.
I've thought about how else to drive a magnet along the inside of a shaft; they're all not-quite-simple.
I'd recommend a small electric motor, driving a fine threaded screw with a hall effect sensor on the motor to tell you where you are, then control it with a little box, like the Dura-Ace electronic shifters. I think there's an open source program for this intended for regular derailleur type electronic shifting.
Or, with as light a spring as you would need for that, maybe just use a common shifter with a pulley type overdrive mounted inbetween somewhere.
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